High-frequency electronic switch, and burst wave generating device using the same and short range radar using the same Number:7,522,004 from the United States Patent and Trademark Office (PTO) owispatent

Title: High-frequency electronic switch, and burst wave generating device using the same and short range radar using the same

Abstract: A high-frequency electronic switch includes a signal input terminal to which a high-frequency signal to be switched is input, a plurality of amplifying circuits with transistors, to respectively amplify the high-frequency signal to be switched sequentially, the amplifying circuits being cascade-connected in a plurality of stages to the signal input terminal, a signal output terminal which is connected to an output section of an amplifying circuit at final stage among the plurality of amplifying circuits, and which outputs the high-frequency signal to be switched sequentially amplified, a control terminal to which a pulse signal serving as a switching signal having a period of a first level and a period of a second level is input, and a supply current control circuit which makes the plurality of amplifying circuits be in an amplification-operational state by supplying operational current to each of the transistors of the plurality of amplifying circuits in a period when the pulse signal input to the control terminal is at the first level, and which makes the plurality of amplifying circuits be in a non-amplification-operational state by stopping supplying operational current to each of the transistors of the plurality of amplifying circuits in a period when the pulse signal is at the second level. The high-frequency electronic switch effectively suppresses leakage of high-frequency signal at the time of off-state by turning on/off between the signal input terminal and the signal output terminal so as to be able to be isolated substantially high-frequency likewise in accordance with a level of the pulse signal input to the control terminal.

Patent Number: 7,522,004 Issued on 04/21/2009 to Saito

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Inventors:	Saito; Sumio (Atsugi, JP)
Assignee:	Anritsu Corporation (Tokyo, JP)
Appl. No.:	10/588,910
Filed:	November 14, 2005
PCT Filed:	November 14, 2005
PCT No.:	PCT/JP2005/020860
371(c)(1),(2),(4) Date:	August 09, 2006
PCT Pub. No.:	WO2006/051948
PCT Pub. Date:	May 18, 2006

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Foreign Application Priority Data

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Nov 15, 2004 [JP]			2004-331029

Current U.S. Class:	330/310 ; 330/98
Current International Class:	H03F 3/04 (20060101)
Field of Search:	330/98,10,150,261,310

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References Cited [Referenced By]

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U.S. Patent Documents

4794342	December 1988	Kimura
5802464	September 1998	Ashida
5838197	November 1998	Tsukuda
5920209	July 1999	Kusumoto et al.
2006/0203936	September 2006	Roovers et al.

Foreign Patent Documents

	54-5315		Jan., 1979		JP
	60-41805		Mar., 1985		JP
	60-62711		Apr., 1985		JP
	64-48506		Feb., 1989		JP
	1-280908		Nov., 1989		JP
	2-244903		Sep., 1990		JP
	5-188137		Jul., 1993		JP
	7-12921		Jan., 1995		JP
	8-313619		Nov., 1996		JP
	2000-244293		Sep., 2000		JP
	2004/091161		Oct., 2004		WO

Other References

Notification Concerning Transmittal of International Preliminary Report on Patentability, Chapter I of the Patent Cooperation Treaty, and Written Opinion of the International Searching Authority, for PCT/JP2005/020860, Dated May 24, 2007. 6 sheets. cited by other . FCC 02-48 New Part 15 Rules, First Report and Order; Apr. 2002. cited by other . FCC 04-285 Second Report and Order and Second Memorandum Opinion and Order; Dec. 16, 2004. cited by other . O'Donnel I et al, "An Integrated, low power, ultra-wideband transceiver architecture for low-rate, indoor wireless systems", IEEE Wireless Communications and Networking Conference, Sep. 4, 2002, pp. 1-8 XP002269840. cited by other . Extended European Search Report dated Aug. 6, 2008, issued in a counterpart European Application. cited by other.

Primary Examiner: Choe; Henry K
Attorney, Agent or Firm: Frishauf, Holtz, Goodman & Chick, P.C.

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Claims

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The invention claimed is:

1. A high-frequency electronic switch comprising: a signal input terminal to which a high-frequency signal to be switched is input; a plurality of amplifying circuits with transistors to respectively amplify the high-frequency signal to be switched sequentially, the amplifying circuits being cascade-connected in a plurality of stages to the signal input terminal; a signal output terminal which is connected to an output section of an amplifying circuit at final stage among the plurality of amplifying circuits, and which outputs the high-frequency signal to be switched sequentially amplified; a control terminal to which a pulse signal serving as a switching signal and having a period of a first level and a period of a second level is input; and a supply current control circuit which makes the plurality of amplifying circuits be in an amplification-operational state by supplying operational current to each of the transistors of the plurality of amplifying circuits in a period when the pulse signal input to the control terminal is at the first level, and which makes the plurality of amplifying circuits be in a non-amplification-operational state by stopping supplying operational current to each of the transistors of the plurality of amplifying circuits in a period when the pulse signal is at the second level, the high-frequency electronic switch which turns on/off between the signal input terminal and the signal output terminal substantially high-frequency likewise in accordance with a level of the pulse signal input to the control terminal.

2. The high-frequency electronic switch according to claim 1, characterized by comprising: a positive-phase signal input terminal and a negative-phase signal input terminal which are provided as the signal input terminal, and to which at least one of positive-phase and negative-phase high-frequency signals is input as the high-frequency signal for being switched; and a positive-phase signal output terminal and a negative-phase signal output terminal which are provided as the signal output terminal, and from which at least one of the positive-phase and negative-phase high-frequency signals is output, wherein the plurality of amplifying circuits which are cascade-connected in a plurality of stages between the positive-phase signal input terminal and the negative-phase signal input terminal, and between the positive-phase signal output terminal and the negative-phase signal output terminal, are respectively configured to be a differential type with a plurality of transistors.

3. The high-frequency electronic switch according to claim 1 or 2, characterized in that the supply current control circuit includes a plurality of constant current circuits which are connected to each of the transistors of the plurality of amplifying circuits, and makes the plurality of amplifying circuits be in an amplification-operational state or a non-amplification-operational state simultaneously or virtually simultaneously by making the plurality of constant current circuits be in an operational state or a non-operational state simultaneously or virtually simultaneously in accordance with a level of the pulse signal input to the control terminal.

4. The high-frequency electronic switch according to claim 3, characterized in that the high-frequency electronic switch is configured such that the plurality of constant current circuits of the supply current control circuit are respectively composed of a plurality of constant current circuits with transistors, and that the pulse signal input to the control terminal is supplied to each of bases of the transistors of the plurality of constant current circuits.

5. The high-frequency electronic switch according to claim 1 or 2, characterized in that the supply current control circuit includes: the plurality of constant current circuits which are connected to each of the transistors of the plurality of amplifying circuits; and a plurality of delay circuits which provide a delay corresponding to a delay in the high-frequency signal to be switched sequentially amplified in the plurality of amplifying circuits with respect to the pulse signal input to the control terminal, and makes the plurality of constant current circuits be in an operational state or a non-operational state in a timewise staggered manner so as to correspond to the delay in the high-frequency signal in accordance with a level of the pulse signal input to the control terminal.

6. The high-frequency electronic switch according to claim 5, characterized in that the high-frequency electronic switch is configured such that the plurality of constant current circuits of the supply current control circuit are respectively constituted of a plurality of constant current circuits with transistors, and that the pulse signal input to the control terminal is supplied to each of bases of the transistors of the plurality of constant current circuits.

7. The high-frequency electronic switch according to claim 2, characterized by further comprising: a synthetic circuit which is connected between the positive-phase signal output terminal and the negative-phase signal output terminal, and which synthesizes and outputs the positive-phase and negative-phase high-frequency signals, serving as the high-frequency signal for being switched, which are sequentially amplified at the plurality of amplifying circuits configured to be a differential type, and are output from the positive-phase signal output terminal and the negative-phase signal output terminal, when positive-phase and negative-phase high-frequency signals are respectively input as the high-frequency signal to be switched to the positive-phase signal input terminal and the negative-phase signal input terminal.

8. A burst wave generating device comprising: a carrier signal generator which continuously outputs a high-frequency carrier signal; and a high-frequency electronic switch which outputs the high-frequency carrier signal output from the carrier signal generator in a burst form, or makes it be in an output-stopped state, wherein the high-frequency electronic switch comprises: a signal input terminal which receives the high-frequency carrier signal; a plurality of amplifying circuits with transistors, to respectively amplify the high-frequency carrier signal sequentially, the amplifying circuits being cascade-connected in a plurality of stages to the signal input terminal; a signal output terminal which is connected to an output section of an amplifying circuit at final stage among the plurality of amplifying circuits, and which outputs the high-frequency carrier signal to be sequentially amplified; a control terminal to which a pulse signal serving as a switching signal having a period of a first level and a period of a second level is input; and a supply current control circuit which makes the plurality of amplifying circuits be in an amplification-operational state by supplying operational current to each of the transistors of the plurality of amplifying circuits in a period when the pulse signal input to the control terminal is at the first level, and which makes the plurality of amplifying circuits be in a non-amplification-operational state by stopping supplying operational current to each of the transistors of the plurality of amplifying circuits in a period when the pulse signal is at the second level, and the high-frequency carrier signal is output in a burst form, or is made to be in an output-stopped state by turning on/off between the signal input terminal and the signal output terminal substantially high-frequency likewise in accordance with a level of the pulse signal input to the control terminal by the high-frequency electronic switch.

9. The burst wave generating device according to claim 8, characterized by comprising: a positive-phase signal input terminal and a negative-phase signal input terminal which are provided as the signal input terminal of the high-frequency electronic switch, and to which at least one of positive-phase and negative-phase high-frequency carrier signals is input as the high-frequency carrier signal; and a positive-phase signal output terminal and a negative-phase signal output terminal which are provided as the signal output terminal of the high-frequency electronic switch, and from which at least one of the positive-phase and negative-phase high-frequency carrier signals is output, wherein the plurality of amplifying circuits which are cascade-connected in a plurality of stages between the positive-phase signal input terminal and the negative-phase signal input terminal, and between the positive-phase signal output terminal and the negative-phase signal output terminal, are respectively configured to be a differential type with a plurality of transistors.

10. The burst wave generating device according to claim 8 or 9, characterized in that the supply current control circuit of the high-frequency electronic switch includes a plurality of constant current circuits which are connected to each of the transistors of the plurality of amplifying circuits, and makes the plurality of amplifying circuits be in an amplification-operational state or a non-amplification-operational state simultaneously or virtually simultaneously by making the plurality of constant current circuits be in an operational state or a non-operational state simultaneously or virtually simultaneously in accordance with a level of the pulse signal input to the control terminal.

11. The burst wave generating device according to claim 10, characterized in that the high-frequency electronic switch is configured such that the plurality of constant current circuits of the supply current control circuit are respectively constituted of a plurality of constant current circuits with transistors, and that the pulse signal input to the control terminal is supplied to each of bases of the transistors of the plurality of constant current circuits.

12. The burst wave generating device according to claim 8 or 9, characterized in that the supply current control circuit of the high-frequency electronic switch includes: a plurality of constant current circuits which are connected to each of the transistors of the plurality of amplifying circuits; and a plurality of delay circuits which provide a delay corresponding to a delay in the high-frequency carrier signal to be sequentially amplified at the plurality of amplifying circuits with respect to the pulse signal input to the control terminal, and makes the plurality of constant current circuits be in an operational state or a non-operational state in a timewise staggered manner so as to correspond to the delay in the high-frequency carrier signal in accordance with a level of the pulse signal input to the control terminal.

13. The burst wave generating device according to claim 12, characterized in that the high-frequency electronic switch is configured such that the plurality of constant current circuits of the supply current control circuit are respectively constituted of a plurality of constant current circuits with transistors, and that the pulse signal input to the control terminal is supplied to each of bases of the transistors of the plurality of constant current circuits.

14. The burst wave generating device according to claim 9, characterized in that the high-frequency electronic switch further comprises a synthetic circuit which is connected between the positive-phase signal output terminal and the negative-phase signal output terminal, and which synthesizes and outputs the positive-phase and negative-phase high-frequency carrier signals serving as the high-frequency carrier signal, which are sequentially amplified at the plurality of amplifying circuits configured to be a differential type, and which are output from the positive-phase signal output terminal and the negative-phase signal output terminal when positive-phase and negative-phase high-frequency carrier signals are respectively input as the high-frequency carrier signal to the positive-phase signal input terminal and the negative-phase signal input terminal.

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Description

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This application is a U.S. National Phase Application under 35 USC 371 of International Application PCT/JP2005/020860 filed Nov. 14, 2005.

TECHNICAL FIELD

The present invention relates to a high-frequency electronic switch, a burst wave generating device using the same, and a short range radar using the same. In particular, the invention relates to a high-frequency electronic switch which employs a technology for preventing leakage of carrier thereof in a burst wave generating device for use in a transmitting unit such as short range radars at a quasi-millimeter waveband (UWB: Ultra-wideband) of 22 to 29 GHz which is assigned for automotive radars, radars for walking support for visually impaired humans, and the like, a burst wave generating device using the same, and a short range radar using the same.

BACKGROUND ART

A pulse radar which searches for an object in a space by using a pulse wave basically has the configuration shown in FIG. 6.

Namely, a transmitting unit 11 receives a trigger signal G output at a predetermined cycle Tg from a control unit 20 which will be described later, by a pulse generator 12.

The pulse generator 12 outputs a pulse signal Pa with a predetermined width synchronous with a trigger signal G to a burst wave generating device 13.

The burst wave generating device 13 outputs a burst wave Pb having a carrier signal with a predetermined frequency in a period when a pulse signal Pa is being input (for example, in a period when a pulse signal Pa is being at a high level). In addition, the burst wave generating device 13 stops outputting a burst wave Pb having the carrier signal in a period when a pulse signal Pa is not input (for example, in a period when a pulse signal Pa is at a low level).

Note that examples of the configuration of the burst wave generating device 13 include a system in which a burst wave having a carrier signal with a predetermined frequency which is continuously output is made intermittent by a switch, and a system in which an oscillation operation of an oscillator oscillating a burst wave having a carrier signal with a predetermined frequency to output is controlled to be on/off.

A burst wave Pb output from the burst wave generating device 13 is amplified by a power amplifier 14, and is supplied to a transmitting antenna 15.

Therefore, a pulse wave Pt with a predetermined width which is synchronous with a trigger signal G is emitted into a space 1.

When the pulse wave Pt is reflected by the body 1a existing in the space 1, the reflected wave Pr is received by a receiving antenna 17 of the receiving unit 16, and a received signal R thereof is detected by a wave-detecting circuit 18.

A signal processing unit 19 analyzes the body 1a existing in the space 1 by determining a timing of a change in a level of a signal H output from the receiving unit 16, or an output waveform in, for example, a timing when a pulse wave Pa is transmitted from the pulse generator 12 of the transmitting unit 11 being as a reference timing.

The control unit 20 performs predetermined various controls onto the transmitting unit 16 and the receiving unit 11 based on processing results of the signal processing unit 19.

Note that a basic configuration of such a radar is disclosed in the following Patent Documents 1 and 2.

Pat. Document 1: Jpn. Pat. Appln. Kokai Publication No. 7-012921

Pat. Document 2: Jpn. Pat. Appln. Kokai Publication No. 8-313619

Radars for automobile use to be put into practical use in recent years among radars having such a basic configuration include two types of the following radars.

Pulse radars of the first type are radars aiming at support at the time of high-speed driving, such as collision prevention and driving control by searching for a narrow angular range at long range on high power using a millimeter waveband (77 GHz).

Pulse radars of the second type are short range radars aiming at support at the time of low-speed driving, such as dead zone assistance for automobile and assistance for putting a car in a garage by searching for a wide angular range at close range on low power using a quasi-millimeter waveband (22 to 29 GHz).

UWB radars using the quasi-millimeter waveband are used as, not only radars for automobile use, but also radars for walking support for visually impaired humans, close range communication system, and the like.

In broadband UWB radars, for example, a short pulse whose width is 1 ns or less can be used, which can realize a radar with a high range resolving power.

DISCLOSURE OF INVENTION

However, in order to realize this UWB radar, there are various sorts of problems to be solved.

One of the important problems is a problem of leakage of a carrier signal of a burst wave output from the transmitting unit 11.

By the way, as described above, a waveband of 22 to 29 GHz is to be used in a UWB radar. However, a RR radiowave emission prohibited band (23.6 to 24.0 GHz) for protecting passive sensors of radio astronomy or earth exploration satellite service (EESS) is included in this band.

In 2002, the Federal Communications Commission (FCC) of USA has disclosed the rule that an average power density is to -41.3 dBm or less, and a peak power density is 0 dBm/50 MH at 22 to 29 GHz in the following Non-Patent Document 1.

In this rule, it is stipulated that a wave angle side lobe is reduced to be -25 dB to -35 dB every several years in order to suppress radio interference onto the aforementioned EESS as well.

Non-Patent Document 1: FCC 02-48 New Part 15 Rules, FIRST REPORT AND ORDER

However, in order to achieve this, it is assumed that a dimension in a vertical direction of an antenna used for a UWB radar is made larger, and that it is difficult to mount the antenna onto a general passenger vehicle.

For this reason, as a method which does not depend on a side lobe of an antenna, the FCC has added the revised rule that a radiation power density at the RR radiowave emission prohibited band is -61.3 dBm/MHz which is less by 20 dB than the previous one in the following Non-Patent Document 2 in 2004.

Non-Patent Document 2: "Second Report and Order and Second Memorandum Opinion and Order" FCC 04-285, Dec. 16, 2004

Conventional UWB radars employ a system in which a continuous wave (CW) from a continuous oscillator is turned on/off by a semiconductor switch.

Because, in this system, a large residual carrier is generated due to the incompleteness in isolation of the switch as shown by the broken line in FIG. 7, the residual carrier is evacuated into an short range device (SRD) band of 24.05 to 24.25 GHz which is assigned for a Doppler radar.

However, there is the serious problem that the SRD band is extremely close to the RR radiowave emission prohibited band, which brings about unavoidable interference with an EESS or the like.

Accordingly, as a radar system utilizing a frequency in the vicinity of the RR radiowave emission prohibited band as a carrier frequency, it is necessary to narrow down a beam in a horizontal direction. Consequently, a dimension in a vertical direction of the transmitting antenna is made large of necessity, and it is extremely disadvantageous at the thought of automobile use or mobile use.

Note that, as described above, in a case of the system in which a burst wave having a carrier signal with a predetermined frequency which is continuously output is made intermittent by a switch, it is necessary to use a high-frequency electron switch by a semiconductor device in a UWB radar system in order to response to a pulse with a narrow width which is, for example, 1 ns or less.

However, because leakage of carrier signal in the off state is great in a high-frequency electric on switch (for example, a diode switch or an analog switch) by a conventional semiconductor device, the problem that a searching range or the like as the radar system is greatly limited becomes prominent.

Further, in a case of a diode switch, configuration is made in many cases so as to be in on state by making electric current flow in a diode via a coil, and it is impossible to favorably response to a pulse with a narrow width such as, for example, a short pulse with a width less than or equal to 1 ns.

In consideration of these circumstances, it has been strongly desired to realize a high-frequency electronic switch in which a speed of response is high even at a frequency band or the like shown by the solid line in FIG. 7, and leakage is little, and to realize a burst wave generating device using the same and a short range radar using the same.

An object of the present invention is to provide a high-frequency electronic switch in which a speed of response is high even at a frequency band or the like of UWB higher than the RR radiowave emission prohibited band, and leakage is little, and to provide a burst wave generating device using the same and a short range radar using the same.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a high-frequency electronic switch comprising:

a signal input terminal (36a) to which a high-frequency signal (C) to be switched is input;

a plurality of amplifying circuits (37A, 37B, 37C) with transistors (Tr) to respectively amplify the high-frequency signal (C) to be switched sequentially, the amplifying circuits being cascade-connected in a plurality of stages to the signal input terminal (36a);

a signal output terminal (36e) which is connected to an output section of an amplifying circuit (37C) at final stage among the plurality of amplifying circuits (37A, 37B, 37C), and which outputs the high-frequency signal (C) to be switched sequentially amplified;

a control terminal (36c) to which a pulse signal (Pa) serving as a switching signal and having a period of a first level and a period of a second level is input; and

a supply current control circuit (38) which makes the plurality of amplifying circuits (37A, 37B, 37C) be in an amplification-operational state by supplying operational current to each of the transistors (Tr) of the plurality of amplifying circuits (37A, 37B, 37C) in a period when the pulse signal (Pa) input to the control terminal (36c) is at the first level, and which makes the plurality of amplifying circuits (37A, 37B, 37C) be in a non-amplification-operational state by stopping supplying operational current to each of the transistors (Tr) of the plurality of amplifying circuits (37A, 37B, 37C) in a period when the pulse signal (Pa) is at the second level, the high-frequency electronic switch which turns on/off between the signal input terminal (36a) and the signal output terminal (36e) substantially high-frequency likewise in accordance with a level of the pulse signal input to the control terminal.

Also, in order to achieve above object, according to a second aspect of the present invention, there is provided a high-frequency electronic switch according to the first aspect of the invention, comprising:

a positive-phase signal input terminal (36b) and a negative-phase signal input terminal (36b') which are provided as the signal input terminal (36a), and to which at least one of positive-phase and negative-phase high-frequency signals (C, C') is input as the high-frequency signal (C) to be switched; and

a positive-phase signal output terminal (36a) and a negative-phase signal output terminal (36a') which are provided as the signal output terminal (36e), and from which at least one of the positive-phase and negative-phase high-frequency signals (C, C') is output,

wherein the plurality of amplifying circuits (37A, 37B, 37C) which are cascade-connected in a plurality of stages between the positive-phase signal input terminal (36a) and the negative-phase signal input terminal (36a'), and between the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b'), are respectively configured to be a differential type with a plurality of transistors (Tr1, Tr2, Tr3, Tr4).

Also, in order to achieve above object, according to a third aspect of the present invention, there is provided a high-frequency electronic switch according to the first or second aspect of the invention, wherein the supply current control circuit (38) includes a plurality of constant current circuits (I1, I2, I3) which are connected to each of the transistors (Tr, Tr1, Tr2, Tr3, Tr4) of the plurality of amplifying circuits (37A, 37B, 37C), and makes the plurality of amplifying circuits (37A, 37B, 37C) be in an amplification-operational state or a non-amplification-operational state simultaneously or virtually simultaneously by making the plurality of constant current circuits (I1, I2, I3) be in an operational state or a non-operational state simultaneously or virtually simultaneously in accordance with a level of the pulse signal (Pa) input to the control terminal (36c).

Also, in order to achieve above object, according to a fourth aspect of the present invention, there is provided a high-frequency electronic switch according to the third aspect of the invention, wherein the high-frequency electronic switch is configured such that the plurality of constant current circuits (I1, I2, I3) of the supply current control circuit (38) are respectively composed of a plurality of constant current circuits (I1, I2, I3, Ill, I12, I13, I14) with transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24), and that the pulse signal (Pa) to the control terminal (36c) is supplied to each of bases of the transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24) of the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14).

Also, in order to achieve above object, according to a fifth aspect of the present invention, there is provided a high-frequency electronic switch according to the first or second aspect of the invention, wherein the supply current control circuit (38) includes: the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) which are connected to each of the transistors (Tr, Tr1, Tr2, Tr3, Tr4) of the plurality of amplifying circuits (37A, 37B, 37C); and a plurality of delay circuits (D1, D2, D3) which provide a delay corresponding to a delay in the high-frequency signal to be switched sequentially amplified in the plurality of amplifying circuits (37A, 37B, 37C) with respect to the pulse signal (Pa) to the control terminal (36c), and makes the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) be in an operational state or a non-operational state in a timewise staggered manner so as to correspond to the delay in the high-frequency signal in accordance with a level of the pulse signal (Pa) to the control terminal (36c).

Also, in order to achieve above object, according to a sixth aspect of the present invention, there is provided a high-frequency electronic switch according to the fifth aspect of the invention, wherein the high-frequency electronic switch is configured such that the plurality of constant current circuits (I1, I2, I3) of the supply current control circuit (38) are respectively constituted of a plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) with transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24), and that the pulse signal (Pa) to the control terminal (36c) is supplied to each of bases of the transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24) of the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14).

Also, in order to achieve above object, according to a seventh aspect of the present invention, there is provided a high-frequency electronic switch according to the second aspect of the invention, further comprising: a synthetic circuit (37D) which is connected between the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b'), and which synthesizes and outputs the positive-phase and negative-phase high-frequency signals (C, C'), serving as the high-frequency signal to be switched (C), which are sequentially amplified at the plurality of amplifying circuits (37A, 37B, 37C) configured to be a differential type, and are output from the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b'), when positive-phase and negative-phase high-frequency signals are respectively input as the high-frequency signal to be switched to the positive-phase signal input terminal (36a) and the negative-phase signal input terminal (36a').

In order to achieve the above object, according to an eighth aspect of the present invention, there is provided a burst wave generating device comprising:

a carrier signal generator (35) which continuously outputs a high-frequency carrier signal; and

a high-frequency electronic switch (36) which outputs the high-frequency carrier signal (C) output from the carrier signal generator (35) in a burst form, or makes it be in an output-stopped state, wherein the high-frequency electronic switch (36) comprises:

a signal input terminal (36a) which receives the high-frequency carrier signal (C);

a plurality of amplifying circuits (37A, 37B, 37C) with transistors (Tr), to respectively amplify the high-frequency carrier signal (C) sequentially, the amplifying circuits being cascade-connected in a plurality of stages to the signal input terminal;

a signal output terminal (36e) which is connected to an output section of an amplifying circuit (37C) at final stage among the plurality of amplifying circuits (37A, 37B, 37C), and which outputs the high-frequency carrier signal (C) to be sequentially amplified;

a control terminal (36c) to which a pulse signal serving as a switching signal having a period of a first level and a period of a second level is input; and

a supply current control circuit (38) which makes the plurality of amplifying circuits (37A, 37B, 37C) be in an amplification-operational state by supplying operational current to each of the transistors (Tr) of the plurality of amplifying circuits (37A, 37B, 37C) in a period when the pulse signal (Pa) to the control terminal (36c) is at the first level, and which makes the plurality of amplifying circuits (37A, 37B, 37C) be in a non-amplification-operational state by stopping supplying operational current to each of the transistors (Tr) of the plurality of amplifying circuits (37A, 37B, 37C) in a period when the pulse signal is at the second level, and the high-frequency carrier signal (C) is output in a burst form, or is made to be in an output-stopped state by turning on/off between the signal input terminal (36a) and the signal output terminal (36e) substantially high-frequency likewise in accordance with a level of the pulse signal (Pa) to the control terminal (36c) by the high-frequency electronic switch.

In order to achieve the above object, according to a ninth aspect of the present invention, there is provided a burst wave generating device according to the eighth aspect of the invention comprising:

a positive-phase signal input terminal (36a) and a negative-phase signal input terminal (36a') which are provided as the signal input terminal of the high-frequency electronic switch, and to which at least one of positive-phase and negative-phase high-frequency carrier signals (C, C') is input as the high-frequency carrier signal (C); and

a positive-phase signal output terminal (36b) and a negative-phase signal output terminal (36b') which are provided as the signal output terminal (36e) of the high-frequency electronic switch (36), and from which at least one of the positive-phase and negative-phase high-frequency carrier signals (C, C') is output, wherein the plurality of amplifying circuits (37A, 37B, 37C) which are cascade-connected in a plurality of stages between the positive-phase signal input terminal (36a) and the negative-phase signal input terminal (36a'), and between the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b'), are respectively configured to be a differential type with a plurality of transistors (Tr1, Tr2, Tr3, Tr4).

In order to achieve the above object, according to a tenth aspect of the present invention, there is provided a burst wave generating device according to the eighth or ninth aspect of the invention, wherein the supply current control circuit (38) of the high-frequency electronic switch (36) includes a plurality of constant current circuits (I1, I2, I3) which are connected to each of the transistors (Tr, Tr1, Tr2, Tr3, Tr4) of the plurality of amplifying circuits (37A, 37B, 37C), and makes the plurality of amplifying circuits (37A, 37B, 37C) be in an amplification-operational state or a non-amplification-operational state simultaneously or virtually simultaneously by making the plurality of constant current circuits (I1, I2, I3) be in an operational state or a non-operational state simultaneously or virtually simultaneously in accordance with a level of the pulse signal (Pa) to the control terminal (36c).

In order to achieve the above object, according to an eleventh aspect of the present invention, there is provided a burst wave generating device according to the tenth aspect of the invention, wherein the high-frequency electronic switch (36) is configured such that the plurality of constant current circuits (I1, I2, I3) of the supply current control circuit (38) are respectively constituted of a plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) with transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24), and that the pulse signal (Pa) to the control terminal (36c) is supplied to each of bases of the transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24) of the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14).

In order to achieve the above object, according to a twelfth aspect of the present invention, there is provided a burst wave generating device according to the eighth or ninth aspect of the invention, wherein the supply current control circuit (38) of the high-frequency electronic switch (36) includes: a plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) which are connected to each of the transistors (Tr, Tr1, Tr2, Tr3, Tr4) of the plurality of amplifying circuits (37A, 37B, 37C); and a plurality of delay circuits (D1, D2, D3) which provide a delay corresponding to a delay in the high-frequency carrier signal (C) to be sequentially amplified at the plurality of amplifying circuits (37A, 37B, 37C) with respect to the pulse signal (Pa) to the control terminal (36c), and makes the plurality of constant current circuits (I1, I2, I3) be in an operational state or a non-operational state in a timewise staggered manner so as to correspond to the delay in the high-frequency carrier signal (C) in accordance with a level of the pulse signal (Pa) to the control terminal (36c).

In order to achieve the above object, according to a thirteen aspect of the present invention, there is provided a burst wave generating device according to the twelfth aspect of the invention, wherein the high-frequency electronic switch (36) is configured such that the plurality of constant current circuits (I1, I2, I3) of the supply current control circuit (38) are respectively constituted of a plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) with transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24), and that the pulse signal (Pa) to the control terminal (36c) is supplied to each of bases of the transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24) of the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14).

In order to achieve the above object, according to a fourteenth aspect of the present invention, there is provided a burst wave generating device according to the ninth aspect of the invention, wherein the high-frequency electronic switch (36) further comprises a synthetic circuit which is connected between the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b'), and which synthesizes and outputs the positive-phase and negative-phase high-frequency carrier signals serving as the high-frequency carrier signal (C), which are sequentially amplified at the plurality of amplifying circuits (37A, 37B, 37C) configured to be a differential type, and which are output from the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b') when positive-phase and negative-phase high-frequency carrier signals (C, C') are respectively input as the high-frequency carrier signal (C) to the positive-phase signal input terminal (36a) and the negative-phase signal input terminal (36a').

In order to achieve the above object, according to a fifteenth aspect of the present invention, there is provided a short range radar comprising:

a transmitting unit (31) which has a burst wave generating device (34) including a carrier signal generator (36) which continuously outputs a high-frequency carrier signal (C) in order to emit a short pulse wave (Pt) with a predetermined width into a space (1) every time a transmission trigger (G) signal is received, and a high-frequency electronic switch (36) which outputs the high-frequency carrier signal (C) output from the carrier signal generator (35) in a burst form, or makes it be in an output-stopped state;

a receiving unit (40) which performs receiving and wave detecting processing onto a reflected wave (Pr) of the short pulse wave (Pt);

a signal processing unit (50) which performs analysis processing on an object (1a) existing in the space (1) based on an output from the receiving unit (40); and

a control unit (60) which performs predetermined control onto at least one of the transmitting unit (31) and the receiving unit (40) based on an analysis result from the signal processing unit (50), wherein the high-frequency electronic switch (36) of the burst wave generating device (34) comprises:

a signal input terminal (36a) which receives the high-frequency carrier signal (C);

a plurality of amplifying circuits (37A, 37B, 37C) with transistors (Tr), to respectively amplify the high-frequency carrier signal (C) sequentially, the amplifying circuits being cascade-connected in a plurality of stages to the signal input terminal (36a);

a signal output terminal (36e) which is connected to an output section of an amplifying circuit at final stage among the plurality of amplifying circuits (37A, 37B, 37C), and which outputs the high-frequency carrier signal (C) to be sequentially amplified;

a control terminal (36c) to which a pulse signal serving as a switching signal having a period of a first level and a period of a second level is input; and

a supply current control circuit (38) which makes the plurality of amplifying circuits (37A, 37B, 37C) be in an amplification-operational state by supplying operational current to each of the transistors (Tr) of the plurality of amplifying circuits (37A, 37B, 37C) in a period when the pulse signal (Pa) to the control terminal (36c) is at the first level, and which makes the plurality of amplifying circuits (37A, 37B, 37C) be in a non-amplification-operational state by stopping supplying operational-current to each of the transistors (Tr) of the plurality of amplifying circuits (37A, 37B, 37C) in a period when the pulse signal is at the second level, and the high-frequency carrier signal (C) is output in a burst form, or is made to be in an output-stopped state by turning on/off state between the signal input terminal and the signal output terminal substantially high-frequency likewise in accordance with a level of the pulse signal (Pa) to the control terminal (36c) by the high-frequency electronic switch (36).

In order to achieve the above object, according to a sixteenth aspect of the present invention, there is provided a short range radar according to the fifteenth aspect of the invention, comprising:

a positive-phase signal input terminal (36a) and a negative-phase signal input terminal (36a') which are provided as the signal input terminal (36a) of the high-frequency electronic switch (36), and to which at least one of positive-phase and negative-phase high-frequency carrier signals (C, C') is input as the high-frequency carrier signal (C); and

a positive-phase signal output terminal (36b) and a negative-phase signal output terminal (36b') which are provided as the signal output terminal of the high-frequency electronic switch (36), and from which at least one of the positive-phase and negative-phase high-frequency carrier signals (C, C') is output, wherein the plurality of amplifying circuits (37A, 37B, 37C) which are cascade-connected in a plurality of stages between the positive-phase signal input terminal (36a) and the negative-phase signal input terminal (36a'), and between the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b'), are respectively configured to be a differential type with a plurality of transistors (Tr1, Tr2, Tr3, Tr4).

In order to achieve the above object, according to a seventeenth aspect of the present invention, there is provided a short range radar according to the fifteenth or sixteenth aspect of the invention, wherein the supply current control circuit (38) of the high-frequency electronic switch (36) includes a plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) which are connected to each of the transistors (Tr, Tr1, Tr2, Tr3, Tr4) of the plurality of amplifying circuits (37A, 37B, 37C), and makes the plurality of amplifying circuits (37A, 37B, 37C) be in an amplification-operational state or a non-amplification-operational state simultaneously or virtually simultaneously by making the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) be in an operational state or a non-operational state simultaneously or virtually simultaneously in accordance with a level of the pulse signal (Pa) to the control terminal (36c).

In order to achieve the above object, according to an eighteenth aspect of the present invention, there is provided a short range radar according to the seventeenth aspect of the invention, wherein the high-frequency electronic switch (36) is configured such that the plurality of constant current circuits (I1, I2, I3) of the supply current control circuit (38) are respectively constituted of a plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) with transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24), and the pulse signal (Pa) to the control terminal (36c) is supplied to each of bases of the transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24) of the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14).

In order to achieve the above object, according to a nineteenth aspect of the present invention, there is provided a short range radar according to the fifteenth or sixteenth aspect of the invention, wherein the supply current control circuit (38) of the high-frequency electronic switch (36) includes: a plurality of constant current circuits (I1, I2, I3) which are connected to each of the transistors (Tr, Tr1, Tr2, Tr3, Tr4) of the plurality of amplifying circuits (37A, 37B, 37C); and a plurality of delay circuits (D1, D2, D3) which provide a delay corresponding to a delay in the high-frequency carrier signal (C) to be sequentially amplified at the plurality of amplifying circuits (37A, 37B, 37C) with respect to the pulse signal (Pa) to the control terminal (36c), and makes the plurality of constant current circuits (I1, I2, I3) be in an operational state or a non-operational state in a timewise staggered manner so as to correspond to the delay in the high-frequency carrier signal (C) in accordance with a level of the pulse signal (Pa) to the control terminal (36c).

In order to achieve the above object, according to a twentieth aspect of the present invention, there is provided a short range radar according to the nineteenth aspect of the invention, wherein the high-frequency electronic switch (36) is configured such that the plurality of constant current circuits (I1, I2, I3) of the supply current control circuit (38) are respectively constituted of a plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14) with transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24), and that the pulse signal (Pa) to the control terminal (36c) is supplied to each of bases of the transistors (Q, Tr11, Tr12, Tr13, Tr14, Tr21, Tr22, Tr23, Tr24) of the plurality of constant current circuits (I1, I2, I3, I11, I12, I13, I14).

In order to achieve the above object, according to a twenty-first aspect of the present invention, there is provided a short range radar according to the sixteenth aspect of the invention, wherein the high-frequency electronic switch (36) further comprises a synthetic circuit which is connected between the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b'), and which synthesizes and outputs the positive-phase and negative-phase high-frequency carrier signals (C, C') serving as the high-frequency carrier signal (C), which are sequentially amplified at the plurality of amplifying circuits (37A, 37B, 37C) configured to be a differential type, and which are output from the positive-phase signal output terminal (36b) and the negative-phase signal output terminal (36b') when positive-phase and negative-phase high-frequency carrier signals (C, C') are respectively input as the high-frequency carrier signal (C) to the positive-phase signal input terminal (36a) and the negative-phase signal input terminal (36a7).

In this way, the high-frequency electronic switch 36 of the present invention is configured such that the plurality of amplifying circuits 37A, 37B and 37C with the transistors which can control to supply operating current are cascade-connected in a plurality of stages between the signal input terminal 36a and the signal output terminal 36e. As a consequence, isolations in a plurality of stages can be obtained, and it is possible to sufficiently suppress leakage of high-frequency carrier signal in off state even within a frequency band of UWB higher than the RR prohibited band of emitting radiowaves.

Further, when the high-frequency electronic switch 36 is used for the burst wave generating device 34, leakage of carrier can be prevented. When, the high-frequency electronic switch 36 is used for the radar system 30, an electric power of the transmitted pulse thereof can be effectively used.

Moreover, in the high-frequency electronic switch 36 in which the respective amplifying circuits 37A, 37B and 37C are configured to be a differential type, higher isolation can be obtained due to the cancellation effect with respect to leakage components in off state in the amplifying circuits 37A, 37B and 37C because the amplifying circuits 37A, 37B and 37C are configured to be a differential type, so that leakage can be more effectively suppressed.

Accordingly, electric power of the transmitted pulse thereof can be more effectively used to the extent that when the high-frequency electronic switch 36 configured to be a differential type is used for the burst wave generating device 34, leakage of carrier can be further prevented, and when the high-frequency electronic switch 36 is used for the radar system 30, leakage can be more effectively suppressed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a configuration of a short range radar 30 which is applied as an embodiment of the present invention.

FIG. 2A is a block diagram illustrating a circuit configuration of a high-frequency electronic switch as the configuration of a principal part of the embodiment in FIG. 1.

FIG. 2B is a block diagram showing a modified example of the circuit configuration of the high-frequency electronic switch as the configuration of the principal part of the embodiment in FIG. 1.

FIG. 3A is a circuit diagram showing a concrete example of the high-frequency electronic switch as the configuration of the principal part of the embodiment in FIG. 1.

FIG. 3B is a circuit diagram showing a more detailed concrete example of the high-frequency electronic switch as the configuration of the principal part of the embodiment in FIG. 1.

FIG. 4 is a graph showing simulation results of ON/OFF characteristics of the high-frequency electronic switch at the time of differential-input in the embodiment of FIGS. 3A and 3B.

FIG. 5 is a graph showing simulation results of ON/OFF characteristics of the high-frequency electronic switch at the time of single input in the embodiment of FIGS. 3A and 3B.

FIG. 6 is a block diagram showing a basic configuration of a conventional pulse radar.

FIG. 7 is a graph showing a spectrum mask of a quasi-millimeter waveband UWB and a desired usable frequency band.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a block configuration of a short range radar 30 to which the present invention is applied.

The short range radar 30 includes a transmitting unit 31, a receiving unit 40, a signal processing unit 50, and a control unit 60.

The transmitting unit 31 generates a short pulse wave Pt with a predetermined width Tp and a predetermined carrier frequency Fc (for example, 26 GHz), and emits it into a space 1 from the transmitting antenna 32 every time a trigger signal G output in a predetermined cycle Tg from the control unit 60 is received.

Note that the transmitting antenna 32 is used commonly with a receiving antenna 41 which will be described later.

The transmitting unit 31 has a pulse generator 33 which generates a pulse signal Pa with a width Tp which is synchronous with a trigger signal G from the control unit 60, a burst wave generating device 34 which outputs a carrier signal with a carrier frequency Fc so as to be a burst form only for a time Tp of receiving a pulse signal Pa from the pulse generator 33, and a power amplifier 39 which amplifies a burst wave output from the burst wave generating device 34, and supplies it to the transmitting antenna 32.

The burst wave generating device 34 includes a carrier signal generator 35 which continuously outputs a carrier signal C with a frequency Fc, and a high-frequency electronic switch 36 (the details thereof will be described later). The high-frequency electronic switch 36 receives a carrier signal C from the carrier signal generator 35 by a signal input terminal 36a, and receives a pulse signal Pa from the pulse generator 33 by a control terminal 36c, thereby turning on/off substantially high-frequency likewise between the signal input terminal 36a and a signal output terminal 36e in accordance with a level of the pulse signal Pa.

Namely, the burst wave generating device 34 outputs a burst wave Pb having a carrier signal with a predetermined frequency to the control terminal 36c of the high-frequency electronic switch 36 in a period when a pulse signal Pa from the pulse generator 33 is being input (for example, a period at a high level of a pulse signal Pa: first level). In addition, the burst wave generating device 34 stops outputting a burst wave Pb having the carrier signal in a period when a pulse signal Pa is not being input (for example, a period at a low level of a pulse signal Pa: second level).

FIG. 2A is a block diagram illustrating a circuit configuration of the high-frequency electronic switch 36 as a configuration of a principal part of the embodiment of FIG. 1.

Namely, the high-frequency electronic switch 36 shown in FIG. 2A is constituted of a plurality of amplifying circuits 37A, 37B and 37C which respectively have transistors Tr for sequentially amplifying a carrier signal C with a high frequency, and which are cascade-connected in a plurality of stages (here, in three stages) between the signal input terminal 36a and the signal output terminal 36e, and a supply current control circuit 38 which supplies electric current required for each of the transistors Tr of the plurality of amplifying circuits 37A, 37B and 37C to operate, and which controls the current supply based on a pulse signal Pa input from the control terminal 36c.

The supply current control circuit 38 has a plurality of constant current circuits I1, I2 and I3 which are connected to each of the transistors Tr of the plurality of amplifying circuits 37A, 37B and 37C, and which supply operational electric current (bias current) to each of the transistors Tr of the plurality of amplifying circuits 37A, 37B and 37C, the constant current circuits I1, I2 and I3 capable of tuning on and off. A pulse signal Pa input from the control terminal 36c is provided to the constant current circuits I1, I2 and I3 to allow the plurality of constant current circuits I1, I2 and I3 to made to be in an operational state or a non-operational state simultaneously or virtually simultaneously in accordance with a level of the pulse signal Pa.

As a consequence, the high-frequency electronic switch 36 makes a carrier signal C intermittent by making the plurality of amplifying circuits 37A, 37B and 37C be in an amplification-operational state or a non-amplification-operational state simultaneously or virtually simultaneously by switching on and off the transistors Tr of the plurality of amplifying circuits 37A, 37B and 37C simultaneously or virtually simultaneously.

Namely, the high-frequency electronic switch 36 receives a carrier signal C input from the signal input terminal 36a by the amplifying circuit 37A at the first stage among the plurality of amplifying circuits 37A, 37B and 37C. When the high-frequency electronic switch 36 is in an operational (on-operating) state, the input carrier signal C is inverted and amplified at the amplifying circuit 37A at the first stage, and is output to the amplifying circuit 37B at the second stage.

Further, the carrier signal C amplified at the amplifying circuit 37A at the first stage is input to the amplifying circuit 37B at the second stage. When the high-frequency electronic switch 36 is in an operational (on-operating) state, the input carrier signal C is inverted and amplified, and is output to the amplifying circuit 37C at the final stage.

Then, the carrier signal C amplified at the amplifying circuit 37B at the second stage is input to the amplifying circuit 37C at the final stage. When the high-frequency electronic switch 36 is in an operational (on-operating) state, the input carrier signal C is inverted and amplified, and is output to the signal output terminal 36e.

Here, operational electric current (bias current) of each of the transistors Tr of the plurality of amplifying circuits 37A, 37B and 37C are supplied by the constant current circuits I1, I2 and I3 of the supply current control circuit 38 connected to each of the transistors Tr in order to make the high-frequency electronic switch 36 be in an operational (on-operating) state.

These constant current circuits I1, I2 and I3 are constituted of transistors (Q) capable of operating in on/off state (refer to FIG. 2B).

Then, each of the transistors (Q) of the constant current circuits I1, I2 and I3 are made to be in on (operational) state via a buffer 38a from the control terminal 36c in a period when a pulse signal Pa input to each of bases the transistors is at a high level (first level)

As a consequence, when the plurality of amplifying circuits 37A, 37B and 37C are made to be in an amplification-operational state by supplying operational current to the transistors Tr thereof, the high-frequency electronic switch 36 is made to be in an operational (on-operating) state, and turns, on state between the signal input terminal 36a and the signal output terminal 36e substantially high-frequency likewise, so tha