JPH06177649A - Fm signal generator and high frequency signal generator for fm radar module - Google Patents

Abstract

PURPOSE:To provide an FM signal generator at a millimeter wave band for a simple and compact FM radar module of a nonradioactive dielectric line form in which the frequency is easily and surely controlled. CONSTITUTION:A generator is constituted of a metal-made diode mount (DM) kept to a ground potential, a printed circuit board (PB) in which 1st and 2nd bias supply lines (B1, B2) of a microstrip line form are formed in both sides in the middle and fixed to a side face of the diode mount (DM), a gun diode (GD) formed integrally with the diode mount (DM), receiving a ground potential at its one terminal from the diode mount and receiving a bias voltage at the other terminal through the 1st bias supply line (B1) formed on the printed circuit board (PB), and a beam lead type varactor diode (VD) mounted between the 1st and 2nd bias supply lines (B1, B2).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FM radar module and a high frequency signal generator used in a millimeter wave band radar device for vehicles.

[0002]

2. Description of the Related Art A vehicle-mounted radar device mounted on a vehicle such as a passenger car and used as a warning device for collision prevention or collision prevention,
High resolution is required because the detection range is set to a close range of several tens of centimeters. In terms of this high resolution, the form of the FM radar is more suitable than the form of the pulse radar. In addition, since the farthest distance measurement range to the target such as a preceding vehicle or an oncoming vehicle is a comparatively short distance of about several hundred meters, radiated radio waves can propagate more than necessary and communication in existing microwave bands can be performed. 60Ghz to avoid interference with equipment
A millimeter wave band radio wave with a large propagation attenuation is suitable. This millimeter wave band is used for the antenna and the F before and after the antenna.
It is also suitable for downsizing the radar module including the M signal generator and the mixer.

Conventionally, the above-mentioned millimeter-wave band FM radar module has been constructed in the form of a microstrip line or a waveguide, but in the former case, the radiation power from the line becomes large and the loss increases, and at the same time, a plurality of modules are produced. There is a problem that interference easily occurs between the modules of the system and the measurement accuracy decreases. In the latter case, there is a problem that the circuit becomes large and expensive.

As a new line format for solving the above problems, the Institute of Electronics, Information and Communication Engineers, Journal Vol. J 73 C-1 No.
3 pp.87-94 (March 1990), "Non-radiative Dielectric Line (Non-Radio Dielectric Line)" as disclosed in Yoneyama et al. Radiat
ive Dielectric waveguide (NRD) is suitable. In this non-radiative dielectric waveguide, a rod-shaped dielectric is inserted between two conductor plates facing each other with a gap slightly smaller than a half wavelength, so that only the propagation along the rod is possible. In this non-radiative dielectric line, the top and bottom of the line are completely shielded by the conductor plates, and the propagation of radio waves that leak to the side of the line is completely blocked because the conductor spacing is less than half a wavelength. . Therefore, the power radiation from the line is extremely small, and radiation loss inside the module and mutual interference between the modules are effectively avoided.

Further, in the non-radiative dielectric line, various parts such as a directional coupler and an isolator can be easily prepared by bringing the lines close to each other or adding ferrite or the like. Therefore, after preparing each part separately, The miniaturization of the entire module can be realized as compared with the conventional microstrip type in which lines are connected to each other. The above-mentioned paper discloses a structure of a compact and high-performance millimeter-wave band transmitter and receiver using a non-radiative dielectric line.

As a millimeter-wave band oscillator and its peripheral circuits constituting the transmitter and receiver, a Gunn oscillator having the configuration shown in FIG. 8 and a millimeter-wave band signal generated by the Gunn oscillator are introduced to an antenna or the like. A configuration with a non-radiative dielectric line is disclosed. This millimeter-wave band oscillator and its peripheral circuits are composed of upper and lower conductor plates 31, which form a non-radiative dielectric line.
32, a diode mount 33 sandwiched between the upper and lower conductor plates, a gun diode 34 held by screwing on the diode mount 33, a printed wiring board 35 fixed to the side surface of the diode mount 33, and a gun diode 34. It is composed of a dielectric rod 40 for guiding the millimeter wave band signal to an antenna (not shown) and a metal foil resonator 41 for guiding the millimeter wave band signal generated by the Gunn diode to the dielectric rod 40.

In the non-radiative dielectric waveguide of FIG. 8, the distance between the upper and lower conductor plates 31 and 32 is set to a value slightly smaller than the half wavelength of the millimeter wave band signal used. For example, if the frequency of the signal is about 60 GHz, the distance between the conductor plates 31 and 32, and hence the thickness of the diode mount 33, is as small as about 2.5 mm. Since the commercially available packaged Gunn diode is mounted on the heat dissipation stud having a diameter of 3 to 4 mm, the processing as shown in FIG. 9 is performed. That is, first, as shown in FIG. 9A, the Gunn diode 35 is screwed to a metal block having a thickness of about 5 to 6 mm, and then, as shown in FIG. , The thickness is reduced to about 2.5 mm, and ridges and valleys of ¼ wavelength are formed to prevent signal leakage.

[0008]

A structure of an oscillator using a Gunn diode as a component of the millimeter-wave band transceiver described in the above article is disclosed. However, an FM signal for forming an FM radar module is disclosed. The optimum configuration of the generator has not been examined. Further, in the Gunn oscillator described in the above-mentioned paper, since complicated processing as shown in FIG. 9 is performed to form a diode mount having a small thickness, there is a problem that manufacturing time and cost are increased. Further, in the Gunn oscillator described in the above-mentioned paper, as shown in FIG. 10, since the depth δ of the step portion of the diode mount DM varies during manufacturing, the lower conductor of the Gunn diode is projected from the surface of the diode mount. There is a problem that the height ε varies and the oscillation characteristic also varies.

Accordingly, one object of the present invention is to provide an FM signal generator of an FM radar module of the non-radiative dielectric line type which can easily and surely control the frequency of the FM signal and is simple and compact. To do. Another object of the present invention is to reduce the manufacturing time and cost by eliminating the complicated processing for reducing the thickness of the diode mount when configuring a high frequency signal generator such as an FM signal generator. is there.

[0010]

An FM signal generator of an FM radar module according to the present invention comprises a metal diode mount which is held at a ground potential, and microstrip type first and second electrodes on both sides of a central portion. And a printed wiring board that is fixed to the side surface of the diode mount and that is formed integrally with the diode mount and receives a ground potential at one terminal from the diode mount and is formed on the printed wiring board. Beam lead type varactor mounted between the Gunn diode which receives a bias voltage at the other terminal through the formed first bias supply line and the first and second bias supply lines formed on the printed wiring board. It is composed of a diode.

[0011]

First, one terminal of the Gunn diode is grounded through the diode mount holding the Gunn diode, and the other terminal is formed on the printed wiring board fixed to the side surface of the diode mount. 1 receives a bias voltage from the bias supply line 1. further,
A beam lead type varactor diode is mounted between the first and second bias supply lines. Therefore, the bias voltage of the Gunn diode is adjusted by the bias voltage supplied through the first bias supply line, and the bias voltage of the varactor diode is adjusted by the difference between the bias voltages applied between the first and second bias supply lines. To be done. Further, by forming the Gunn diode integrally with the diode mount, complicated processing for reducing the thickness of the diode mount is not required, and variations in characteristics due to variations in protrusion height when mounting as a separate body. Has been resolved.

[0012]

1 is a perspective view showing the configuration of an FM signal generator 10 and its peripheral portion according to an embodiment of the present invention together with upper and lower conductor plates 1 and 2 constituting a non-radiative dielectric waveguide, and DM
Is a metal diode mount that is held at ground potential,
PB is a printed wiring board fixed to the side surface of the diode mount DM, B1 and B2 are first and second microstrip type bias supply lines formed on both sides of the central portion of the printed wiring board PB, GD is a Gunn diode, VD is a beam lead type varactor diode, MP is a rectangular metal pattern formed between the bias supply lines B1 and B2 of the printed wiring board PB, and L1 and L2 are lead wires connected to the bias supply lines B1 and B2. Further, 11 is a metal foil resonator, and 21 is a dielectric rod forming a non-radiative dielectric line.

The Gunn diode GD is formed integrally with the diode mount DM as shown in the perspective view of FIG. 2 and the sectional view of FIG. That is, the diode mount G
The pellet Ga of the Gunn diode is fixed on the disk-shaped pad formed at the center of D by thermocompression bonding or soldering in an upside down form with the active layer with large heat generation facing downward, The ground potential is supplied to one terminal from the diode mount GD which is maintained at the ground potential. Cylindrical ceramics Gb are planted on the diode mount GM via a metallization layer so as to surround the peripheral portion of the gun element Ga, and a gold ribbon Gd connected to the other terminal of the gun element is provided at the tip portion thereof. And a metal cover plate Gc is attached.

FIG. 4 is a plan view showing the structure of the printed wiring board PB, and FIG. 5 is a plan view showing the mounting state of the Gunn diode GD and the varactor diode VD on the printed wiring board.

The metal cover plate Gc to which the other terminal of the gun diode pellet GD is connected is printed through a through hole H formed in a printed wiring board PB fixed to the side surface of the diode mount DM with an adhesive or the like. The gold foil GL that appears on the surface side of the wiring board PB and is stretched by thermocompression bonding between the first bias supply line B1 formed on the surface of the printed wiring board PB and the metal pattern P is also electrically bonded by thermocompression bonding. Connected to.

Between the metal pattern MP formed on the printed wiring board PB and the second bias supply line B2,
A beam lead type varactor diode VD is mounted by thermocompression bonding. Therefore, the bias voltage applied to the first bias supply line adjusts the bias voltage of the Gunn diode, and the difference between the bias voltages applied between the first and second bias supply lines adjusts the bias voltage of the varactor diode. It

First and second bias supply lines B1 and B2
In each of the above, the width of the track is repeated at regular intervals.
A low-pass filter having a plurality of stages is formed, and this fixed period is set to ¼ of the wavelength of the millimeter-wave band FM signal to be generated by the FM signal generator of this embodiment. According to this embodiment, the frequency of this FM signal is set to about 60 GHz, so that the line width of the low-pass filter is about
It is repeated with a period of 1.25 mm. In this case, the distance between the conductor plates 1 and 2 forming the non-radiative dielectric line, and hence the height of the side surface of the diode mount DM, is set to a value slightly smaller than a half wavelength of the FM signal, that is, a value of about 2.5 mm. .

FM generated by the FM signal generator 10 of FIG.
The frequency of the signal can be roughly adjusted by the dimensions a and b shown in FIG. 5 of the rectangular metal pattern MP, and
Metal foil resonator 11 installed between dielectric rod 21
It was confirmed that it can be finely adjusted by. An example of this is shown below.

When one dimension b is fixed to 0.3 mm and the other dimension a is changed, the oscillation frequencies before and after being incorporated in the non-radiative dielectric waveguide of FIG. 1 change as shown in Table 1 below. did.

When one dimension a is fixed to 0.8 mm and the other dimension b is changed, the oscillation frequencies before and after being incorporated into the non-radiative dielectric waveguide of FIG. 1 change as shown in Table 2 below. did.

FIG. 7 is a plan view showing the configuration of an FM radar module including the FM signal generator according to the embodiment of the present invention shown in FIG. 1. 1 is an upper conductor plate, 10 is an FM signal generator, 11 is a metal foil resonator, 12 is an isolator, 13
Is a directional coupler, 14 is a transmitting antenna, 15 is a receiving antenna, 16 is a single diode mixer, 21, 2
Reference numerals 2 and 23 are dielectric rods.

The FM signal generated by the FM signal generator 10 of this embodiment is propagated along the dielectric rod 21 and supplied to the input terminal of the isolator 12, and the output terminal of the isolator 12 linearly induces a dielectric signal. It is output to the body rod 22. The linear dielectric rod 13 and the semicircular dielectric rod 23 arranged close to the linear dielectric rod 13 form the directional coupler 13, and a part of the FM signal output from the isolator 12 is It moves to the dielectric rod 23 and is radiated to the outside from the transmitting antenna 14 formed at the tip of one of the rods. The remaining part of the FM output from the isolator 12 propagates along the linear dielectric rod 22 to its tip and is supplied as a local signal to the single diode mixer 16 formed therein.

Of the reflected waves from the object, the receiving antenna 15
Part of the received signal is transferred to the linear dielectric rod 22 through the directional coupler 23 and supplied to the single diode mixer 16, and the remaining part is re-radiated from the transmitting antenna 14. It The single diode mixer 16 receives a local signal supplied from the output terminal of the isolator 12 via the dielectric rod 22, and a reflected wave supplied from the receiving antenna 15 via the directional coupler 13, and outputs both signals. A beat signal is generated by mixing and is output to the coaxial line L3 that is drawn out between the upper and lower conductor plates.

On the other hand, the reflected wave from the object is also received by the transmitting antenna 14, which propagates to the receiving antenna 15 along the semicircular dielectric rod 23 and is radiated again from there. Further, a part of the reflected wave received by the transmitting antenna 14 is supplied to the isolator 12 through the directional coupler 13 and the dielectric rod 22, and is absorbed by the non-reflection end 24 thereof. As described above, in the radar module of FIG. 6, since the transmitting and receiving antennas 14 and 15 share the directional coupler 13, re-radiation and re-radiation from each antenna occur, and the reflected wave received with this re-radiation occurs. Is a unnecessary wave that is re-input to the single diode mixer 13 later than the originally necessary reflected wave. However, since this unwanted wave is generated by the FM signal that reciprocates between the antenna and the reflecting object more than twice, it is sufficiently lower than the originally necessary reflected wave in consideration of the relatively low antenna gain of transmission and reception and large spatial propagation loss. It becomes a level and the influence on the radar function can be ignored.

The structure in which the Gunn diode and the mount are integrated has been described above by taking the case of the FM signal generator as an example. However, this configuration is not limited to the FM signal generator and can be extended to a high frequency signal generator using a Gunn diode.

[0026]

Since the FM oscillator of the FM radar module according to the present invention is configured as described above, it can be used as a millimeter wave band FM signal generator for a non-radiative dielectric line type FM radar module. There is an effect that the frequency can be controlled easily and surely and a simple and small size can be realized.

Further, since the high frequency signal generator such as the FM oscillator of the FM radar module according to the present invention has a structure in which the Gunn diode is formed integrally with the diode mount, it is necessary when using a relatively high frequency FM signal. The effect that complicated processing for reducing the thickness of the diode mount which becomes the above becomes unnecessary and the cost can be reduced is achieved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an FM signal generator of an FM radar module according to an embodiment of the present invention together with relevant parts of the FM radar module.

FIG. 2 is a perspective view showing an integrated structure of a diode mount and a Gunn diode of the above-described embodiment.

FIG. 3 is a cross-sectional view showing an integrated configuration of the diode mount and the Gunn diode of the above embodiment.

FIG. 4 is a plan view showing the configuration of the printed wiring board of the above embodiment.

FIG. 5 is a plan view showing how the Gunn diode and the varactor diode are mounted on the printed wiring board of the above embodiment.

FIG. 6 is an equivalent circuit diagram of the FM signal generator of the above embodiment.

FIG. 7 is a plan view showing the overall configuration of a non-radiative dielectric line type FM radar module incorporating the FM signal generator of the above embodiment.

FIG. 8 is an exploded perspective view showing the configuration of a conventional Gunn diode oscillator.

9 is a perspective view showing a method for manufacturing a diode mount to which the Gunn diode of FIG. 8 is screwed.

10 is a sectional view showing the structure of a diode mount to which the Gunn diode of FIG. 8 is screwed.

[Explanation of symbols]

10 FM signal generator 1, 2 upper and lower conductor plates constituting a non-radiative dielectric waveguide DM metal diode mount GD gun diode Ga gun element Gb columnar ceramics Gc metal lid plate Gd gold lead PB printed wiring board B1 No. 1 Bias supply line B2 2nd bias supply line VD Beam lead type varactor diode L1, L2 Bias supply line B1, B2 Lead line connected to

Claims (3)

[Claims] 1. An FM radar module in which an FM signal generator, a transmitting / receiving antenna of a non-radiative dielectric line, and a mixer are connected via a directional coupler of a non-radiative dielectric line, wherein the FM signal generator is , A metal diode mount that is held at ground potential, and microstrip type first and second sides on both sides of the central part
And a printed wiring board that is fixed to the side surface of the diode mount and that is formed integrally with the diode mount and receives a ground potential at one terminal from the diode mount and is formed on the printed wiring board. Beam lead type varactor mounted between the Gunn diode which receives a bias voltage at the other terminal through the formed first bias supply line and the first and second bias supply lines formed on the printed wiring board. An FM signal generator of an FM radar module, which is composed of a diode. 2. The rectangular metal pattern according to claim 1, wherein a rectangular metal pattern for adjusting the oscillation frequency of the Gunn diode is formed on the printed wiring board between the first and second bias supply lines by adjusting the dimensions. The other terminal of the Gunn diode is connected to both the first bias supply line and the metal pattern arranged on both sides thereof, and the varactor diode is connected to the metal pattern and the second bias supply line. The FM radar module, which is mounted between the two. 3. A non-radiative dielectric line composed of upper and lower parallel conductor plates and a dielectric rod held between these parallel conductor plates, and a Gunn diode held between the upper and lower parallel conductor plates and on a side surface. A metal diode mount, a printed wiring board having a microstrip type bias supply line formed on the side surface of the diode mount for supplying a bias voltage to the gun diode, and a high frequency signal generated by the gun diode. A high-frequency signal generator including a metal foil resonator for propagating to a dielectric rod of the non-radiative dielectric line, wherein the Gunn diode mount directly holds a pellet of the Gunn diode by thermocompression bonding or soldering. High frequency signal generator characterized by.