JP2003270325A - Planar antenna integrated-type doppler module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar antenna integrated-type Doppler module wherein the Doppler module is miniaturized by using a planar antenna while having a specific structure allowing a Doppler module circuit part to be connected to the planar antenna with high consistency. <P>SOLUTION: A radiator pattern 12 is formed on one surface side of a dielectric substrate 11. An antenna part 1 has a feeding terminal formed on the other surface of the substrate 11 and connected to the pattern 12. A Doppler module circuit part 2 is provided, on one surface side of a substrate 21, with circuit components such as an unillustrated oscillator and transmission lines for transmitting radio waves from the oscillator, and is provided with a radio wave output terminal on the other surface side of the substrate 21 while being covered with a shield case 22. The output terminal and the feeding terminal are connected to each other with the other surface side of the substrate 11 standing opposite to the other surface side of the substrate 21. The antenna part 1 and the circuit part 2, excepting their terminal parts, are bonded to each other by using an adhesive, etc., with gland films 14 and 24 interposed between them. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Doppler module (transmission / reception of a Doppler radar) which detects a received wave whose frequency is shifted by the movement of an object by using the Doppler effect and detects the moving speed or the moving condition of the object. Circuit part). More specifically, the present invention relates to a planar antenna integrated type Doppler module capable of achieving high performance in a small size by forming a circuit portion of a Doppler module on a substrate, forming an antenna for transmitting and receiving radio waves by a planar antenna, and joining the both.

[0002]

2. Description of the Related Art A method of detecting the moving speed of an object by utilizing the Doppler effect by radio waves (electromagnetic waves having a wavelength of 10 ^-4 m or more including microwaves and millimeter waves) is used in various fields. Has been done. This type of Doppler module has been put into practical use as an oscillation source using a Gunn diode, a high frequency FET, or the like. For example, as shown in FIG. A horn antenna is generally used as the radiator, and the Doppler module circuit section also has a waveguide output structure.

That is, FIG. 8A shows a simple configuration example using a Gunn diode, in which the Gunn diode 41 is inserted into a cavity resonator 42 of a waveguide, and the radio wave oscillated by the Gunn diode 41 is horn antenna 43. The reflected wave transmitted from the object and reflected by the object returns to the horn antenna 43, and is received by the wave detector 44 provided in the cavity of the waveguide,
The signal processing is performed by a detection circuit (not shown). On the other hand, in the example using the high frequency FET, the oscillator 45 including a power supply circuit is formed on the printed circuit board or the like by the high frequency FET and the strip line.
As shown in FIG. 5, as the transmission power, the reflected wave reflected by the object is coupled by the cavity resonator 42 of the waveguide through the probe 46, is also transmitted from the horn antenna 43, and is reflected by the receiving probe 47. The detection circuit 48 receives the signal and processes the signal. The oscillation circuit 45 and the detection circuit 48 are housed in a case such as a metal housing so as not to be affected by external noise, and have a structure in which only the probe is exposed. It is adjusted by adjusting the plunge length of.

The Doppler module having the horn antenna structure can narrow the directivity and is excellent in the control of the directivity, which is convenient for measuring the speed of a specific object. Since it is a waveguide structure, there is a problem that the device becomes large and the handling is inconvenient. On the other hand, recently, the characteristics of a planar antenna in which a radiation element is formed on a dielectric substrate have been improved, and the use of a planar antenna as a Doppler module has been studied.

[0005]

If a Doppler module using a plane antenna is used, for example, a monitoring device for the bathing of an elderly person, a device for remotely grasping the living condition of a living alone in the room, a visitor at a store It is suitable for use as a detection device, a monitoring device for monitoring intrusion of a suspicious person, and the like, and is convenient in terms of mounting because it is miniaturized. However, as mentioned above, the conventional Doppler module is formed to correspond to the waveguide structure, so even if you try to change only the antenna to a planar antenna, the waveguide output will be striplined via the coaxial line. Must be converted to.
Therefore, there is a problem that the conversion unit becomes complicated and expensive. Further, there is a problem in that impedance matching is not sufficiently performed in the conversion unit, reflection occurs, performance deteriorates, and heat loss occurs in the conversion unit.

The present invention has been made in order to solve such a problem, and an object thereof is to miniaturize a Doppler module by using a planar antenna and to provide a joint between a Doppler module circuit portion and a planar antenna. It is an object of the present invention to provide a Doppler module integrated with a planar antenna having a specific structure capable of connecting with good matching.

Another object of the present invention is to provide a planar antenna-integrated Doppler module having a structure in which circuit components can be reduced and miniaturized when not only the velocity of an object but also the moving direction of the object is measured by the Doppler module. To do.

[0008]

A planar antenna-integrated Doppler module according to the present invention comprises (1) a dielectric substrate, a radiator pattern formed on one side of the dielectric substrate, and a connection to the radiator pattern. And an antenna section comprising a power supply terminal formed on the other surface of the dielectric substrate, and (2)
A circuit board, an oscillator provided on one side of the circuit board for generating a transmission wave, a transmission line for transmitting the transmission wave from the oscillator, and a part of the transmission wave from the oscillator and a reception wave reflected by an object And a circuit component having at least a mixer for mixing, a radio wave output terminal provided on the other surface side of the circuit board connected to an end side of the transmission line opposite to the oscillator, and provided on the circuit board. A Doppler module circuit section comprising a shield case that covers the circuit component, and the power supply terminal and the radio wave output terminal with the other surface side of the dielectric substrate and the other surface side of the circuit board facing each other. Are connected, and the antenna section and the Doppler module circuit section are joined with the ground film interposed therebetween except for the terminal section.

With this structure, semiconductor parts such as the oscillator and the mixer are mounted on the circuit board.
Since the transmission line and the radio wave output terminal can all be configured by strip lines or the like, they can be configured by strip lines or the like suitable for connection with the planar antenna. Moreover, since the radio wave output terminal is led out to the back surface of the circuit board, it is possible to connect the flat antenna whose feed portion is led out to the back surface side of the dielectric substrate and the back surface to each other by using the same strip line or the like. It can be connected by a transmission line system. As a result, if the radio wave output terminal of the Doppler module circuit part and the power feeding part of the planar antenna are formed to have the same impedance, respectively, the problem of discontinuity due to the junction of the transmission lines in the microwave circuit does not occur, By matching the back surfaces to each other and joining them together, a matched high-performance Doppler module with a planar antenna can be manufactured.

If the radio wave output terminal and the power feeding terminal are respectively formed of 50 Ω strip lines, it is particularly easy to match them.

The Doppler module circuit section is switched to the oscillator that performs a pulse operation, the first switch circuit that alternately switches the pulse output of the oscillator to two lines whose phases are different by 90 °, and the two lines. One mixer for mixing a part of each of the pulse outputs and a received wave reflected by the object of each pulse output, and an output of the mixer in synchronization with the first switch circuit By having a structure having a first output corresponding to two different phases and a second switch circuit separating into a second output, two radio waves having different phases by 90 ° for knowing the moving direction of the object. Information can be obtained by one mixer, and the distance information (moving direction) can be known by a very small Doppler module.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a planar antenna integrated Doppler module of the present invention will be described with reference to the drawings. The planar antenna integrated type Doppler module according to the present invention has a radiator pattern 12 formed on one surface side of a dielectric substrate 11 and a radiator pattern 12 as shown in FIG. An antenna unit 1 connected to the other surface of the dielectric substrate 11 to form a power supply terminal 13 (see FIG. 2), an oscillator (not shown) on one surface of the circuit board 21, a transmission line for transmitting radio waves from the oscillator, and the like. Of the dielectric substrate 11 and the Doppler module circuit section 2 provided with the radio wave output terminal 23 (see FIG. 3) on the other surface side of the circuit board 21 while being covered by the shield case 22. The other surface side and the other surface side of the circuit board 21 are faced to each other and the radio wave output terminal 23 described above is provided.
And the power supply terminal 13 are connected to each other, and the ground films 14 and 24 are sandwiched except for the terminal portion, and they are joined by an adhesive or the like.

The antenna section 1 is formed in a structure, for example, as shown in the plan view and rear view of FIG. That is, the dielectric substrate 1 made of ceramics or the like
The radiator pattern 12 is provided on one surface (front surface) 1 by a method of printing a metal such as an alloy containing silver in a desired pattern and baking the metal. A power supply unit 13 is formed on the other surface (back surface) of the radiator pattern 12 via a side surface of the dielectric substrate 11 or a through hole provided in the dielectric substrate 11 so as to be connected to a part of the radiator pattern 12. By forming the radiator pattern so that the impedance of the power feeding portion 13 when viewed from the side of the radiator pattern 12 becomes 50Ω, it is easy to match when connecting to the output terminal of the Doppler module circuit portion 2. It is preferable because loss such as reflection can be reduced. On the back surface of the dielectric substrate 11, a similar metal film is provided by printing or sputtering except the vicinity of the power feeding portion, and a ground film (ground conductor) 14 is formed.

This radiator pattern 12 is shown in FIGS.
Not limited to the pattern shown in, depending on the purpose of use,
Various patterns are formed depending on the case where the directivity is narrowed down, the case where a wide range is covered, and the like. If the radiator pattern is enlarged and the opening is enlarged, the directivity becomes sharper,
If the opening is made smaller, the directivity becomes gentler, and radio waves are radiated in a wide range. Further, as the dielectric substrate 11,
It is preferable to use a dielectric having a large dielectric constant because the antenna can be downsized, but usually a ceramic or Teflon (registered trademark) substrate can be used.

The Doppler module circuit section 2 has an oscillator (not shown) on one surface (front surface) side of the circuit board 21 made of a printed board or the like, as shown in FIG. A transmission line for transmitting radio waves from the oscillator, and circuit components such as a mixer that mixes a part of the radio waves from the oscillator with the received wave (reflected wave) reflected by the object are provided so as to configure the transmission / reception circuit unit. A radio wave output terminal 23 for transmitting a radio wave oscillated by an oscillator is provided so as to be connected to an end of a transmission line (not shown) and exposed on the other surface (back surface) of the circuit board 21. The radio wave output terminal 23 is configured such that the impedance when viewed from the circuit section side is 50Ω, so that the power feeding section 13 of the antenna section 1 is formed.
It is preferable since the matching can be achieved and the loss due to the reflection can be reduced when the above is joined. The radio wave output terminal 23 also serves as an input terminal for the received wave reflected by the object.

On the front surface side of the circuit board 21, the circuit board 21
A shield case 22 made of a metal plate or the like for covering circuit components provided on the front surface of the output terminal 2 is provided on the back surface of the circuit board 21 as with the dielectric substrate 11.
A ground film (ground conductor) 24 is formed by providing a metal film on almost the entire surface except 3 and its periphery. This prevents the intrusion of radio waves from the outside and suppresses the generation of noise. However, it is not always necessary to provide the ground film 24 on the back surface of the circuit board, and since the back surface of the dielectric substrate 11 and the back surface of the circuit board 21 are faced to each other and bonded as will be described later, one of the ground films is used. It may be formed on the back surface of the substrate.
Further, a structure may be adopted in which a ground film is not provided on any of the substrates and a metal plate is interposed between the two when bonding them. In addition, in FIG.
Reference numerals 26 and 27 denote a ground terminal, a power supply terminal and a Doppler wave output terminal, respectively.

The transmitting / receiving circuit portion formed on the surface of the circuit board 21 is composed of circuit components whose basic circuit is shown in the block diagram of FIG. 4, for example. That is,
The oscillator 31 includes the first and second branch circuits (directional couplers) 35a and 35b and the transmission line 3 such as a strip line.
It is connected to the radio wave output terminal 23 via 2. First
A part of the output of the oscillator is branched by the branch circuit 35a of FIG. 2 and is input to the mixer 37 via the transmission line 32. The received wave reflected by the object and input to the output terminal 23 passes through the second branch circuit 35b. The output of the oscillator 31 is mixed with the received wave through the mixer 37, and the mixer 37 outputs the intermediate frequency signal in which the phase shift of the received wave reflected by the object is captured. This is amplified by the amplifier 38 and sent to an external signal processing circuit via the output terminal 27 (see FIG. 3). The first and second branch circuits 35a and 35b are for branching a part of the transmission wave from the main transmission line 32 and the reception wave input to the output terminal 23 to the mixer 37 side, and examples described later. As described above, for example, one 3 dB coupler can be used for both.

As the oscillator 31, for example, a Gunn oscillator, an impat oscillator, a semiconductor oscillator such as an FET can be used. The oscillator 31 may be a continuous wave or may be a pulse oscillator as in an example described later. Although a mixer diode is used as the mixer 37, it may be a bipolar transistor or FET.

With this configuration, the back side of the substrate of the antenna section formed by the planar antenna and the back side of the substrate of the Doppler module circuit section formed in a planar shape face each other, and the power feeding section and the output terminal section are connected. Since they are simply joined as described above, it is possible to obtain a very compact and high-performance Doppler module that can be sufficiently matched with each other while being manufactured very easily.

The above-mentioned example of the transmission / reception circuit section is the basic structure of the Doppler radar, and it is possible to know the movement of the object and its speed, but if it is possible to know whether the movement is approaching or moving away, for example, at a storefront. Can detect a wide range of whether a customer came to the store or returned. As a method of knowing the near / far information such as approaching or moving away, the output of the oscillator used as the local oscillator is taken out in two directions (taken in three directions together with the one for transmission), and the phase of one of them is shifted by 90 °. A method is known in which one is input to the first mixer, the other is input to the second mixer without changing the phase, the respective intermediate frequencies are generated, and the direction of the phase shift is detected. There is. However, in this method, the output of the oscillator is branched in two directions for local oscillation, two mixers are required, and the outputs of the mixers must be amplified separately, and the number of parts is increased. However, the device becomes large in size, and it is not suitable for the small and inexpensive Doppler module as in the present invention. An improved example of the Doppler module circuit portion is shown in FIG. 5 in a block diagram similar to FIG.

The example shown in FIG.
No. 01-397255, it is a configuration example of a Doppler module that also knows distance information of an object by one mixer. That is, on the output side of the oscillator 31 that performs a pulse operation, a first switch circuit 361 that alternately switches its output to two lines 32 and 39 whose phases are different by 90 ° is provided, and is switched to the two lines 32 and 39. Pulsed output is integrated into one transmission line 32,
For example, it is connected to the output terminal 23 via the 3 dB coupler 35. A mixer diode as a mixer 37 that mixes a part of the transmitted wave and the received wave received by the antenna unit 1 and input to the output terminal 23 is connected to one port of the 3 dB coupler 35, and its output side. To the second switch circuit 36 via the coil 30 for high frequency cutting.
2 is connected. The output side of the second switch circuit 362 has a first amplifier 381 and a second amplifier 382.
Are connected to each other, and the respective outputs are sent to the signal processing circuit as the output 1 and the output 2.

As the oscillator 31, for example, by driving the oscillator 31a as in the above-mentioned example with the pulse generated by the pulse generator 31b, or by turning on and off the continuously oscillating high frequency by the pulse,
A pulse-modulated oscillator 31 is used. The pulse has a pulse width of about 1 to 10 μsec and a duty cycle of about 0.01 to 0.001.

The first switch circuit 361 and the second switch circuit 362 are configured to be switched in synchronization with each other. For example, the first switch circuit 361 is π / 2.
When connected to the phase shifter 39 side, the output of the mixer 37 is connected to the first amplifier 381 side and output as the output 1. When the first switch circuit 361 is connected to the transmission line 32, The output of the mixer 37 is connected to the second amplifier 382 side and is output as the output 2. As the switch circuits 361 and 362, for example, electronic switches made of semiconductor elements such as PIN diodes and FETs can be used. In order to synchronize both switches 361 and 362, both switches 361 and 362 can be synchronized by turning on and off the first and second switch circuits 361 and 362 with a pulse that causes the oscillator 31a to perform a pulse operation, for example. .

As described above, the 3 dB coupler 35
May be an ordinary directional coupler, and the mixer 37 and the transmission lines 32, 37 may be the same as those used in the conventional Doppler module. In order to obtain information, it is necessary to mix the local oscillator and the received wave that are out of phase with each other by 90 degrees.
It is characterized in that it is performed by one mixer and the output is separated by those having different phases.

Next, the operation of this Doppler module will be described. First, a Doppler module that performs a pulse operation will be described. Generally, the transmitted wave of the Doppler radar is represented by P _T = A ₁ sin (ωt + θ _i ) (1), and when the distance between the antenna and the object is L, the received wave is P _R = A ₂ sin (ωt + 2βL) (2) Here, if the wavelength of the high-frequency oscillator is λ, β
= 2π / λ, θi represents the initial phase. Output P of mixer
_{Since M} is a combination of equations (1) and (2), P _M = A ₃ sin2βL (3). That is, Equation (3) As is clear from, the output P _M of the mixer, not within the initial phase theta _i of the transmitted pulse not relevant to the initial phase theta _i of the transmission pulse, the pulse output Even if a Doppler wave is formed, its continuity is maintained as shown in FIG. In this case, there are many high-frequency repetitions in one pulse, and the pulse repetition frequency must be sufficiently higher than the frequency of the Doppler wave.

Therefore, in the configuration shown in FIG.
Even if the switch circuit 361 switches to the two lines 39 and 32 having different phases by 90 ° as a transmission output, the phase difference does not appear in the received wave input to the mixer 37.
A reception waveform similar to the reception waveform when transmitting with the output of the same normal phase is obtained. On the other hand, a part of the transmission wave as the local oscillator that is mixed by the mixer 37 is mixed with the pulses whose phases are different by 90 °. For example, if the phase is different by 90 ° for each pulse, the received wave will always be a continuous received wave and the Doppler waves will alternate 90 °.
It will be combined with pulses of different local oscillators. As a result, the output of the mixer is alternately separated pulse by pulse,
By taking out via the first and second amplifiers 381 and 382, respectively, FIGS. 6A and 6B show the relationship between the Doppler waves of the output 1 and the output 2 when the object is approaching and when the object is moving away. As shown, the same Doppler wave relationship as with two conventional mixers is obtained from one mixer.

That is, the output 1 of the Doppler wave obtained by the received signal and the local signal whose phase is delayed by 90 °
And the output 2 of the Doppler wave obtained by the received signal and the local signal whose phase is not delayed, the output 1 is 9 times the output 2 as shown in FIG.
If the phase is delayed by 0 ° and the object moves away,
As shown in (b), the phase of output 2 lags the phase of output 1 by 90 °. Therefore, with the configuration shown in FIG. 5, by processing the two outputs 1 and 2 obtained from the mixer 37, not only the velocity but also the perspective information can be obtained. Here, the velocity of the object can be calculated from the frequency of the Doppler wave shown in FIG. In FIG. 6, the pulse output obtained from the mixer is shown by a line without width, and the envelopes thereof are shown as output 1 and output 2.

[0028]

According to the present invention, the Doppler module circuit portion is formed on one surface side of the circuit board, and the radio wave output terminals thereof are led out to the other surface side of the board and formed on the back surface side of the planar antenna. Since it is formed so that it can be connected only by facing the power feeding unit, if the radio wave output terminal and the power feeding unit are respectively formed to have the same impedance in the same transmission line system such as strip line, the module circuit It is possible to connect the parts and the planar antenna part so that their backs are joined to each other with a very good degree of matching. As a result, it is possible to obtain a Doppler module integrated with a planar antenna, which can be made flat and which is very easy to manufacture, small in size, and high in performance.

Further, the Doppler module circuit section is pulsed to produce an output, and the pulse causes a phase shift of 90 degrees.
° By using two different types of transmission outputs and extracting the outputs of the mixer in synchronization with the pulses with different phases, the speed information due to the Doppler effect and the target object are approaching or moving away from each other by one mixer. You can get both perspective information of what you are doing. as a result,
With a very compact Doppler module, it is possible to know the distance information of the object.

[Brief description of drawings]

FIG. 1 is a configuration explanatory diagram of an embodiment of a Doppler module according to the present invention.

FIG. 2 is a structural description of an upper surface and a back surface of the antenna unit shown in FIG.

FIG. 3 is an external structural explanatory view of a Doppler module circuit unit shown in FIG. 1.

FIG. 4 is a diagram illustrating a basic configuration of a Doppler module circuit unit.

FIG. 5 is a configuration explanatory diagram of a Doppler module circuit unit when knowing the perspective information of an object.

FIG. 6 is an explanatory diagram for simultaneously detecting output 1 and output 2 of the mixer of the Doppler module circuit shown in FIG. 5 to detect perspective information.

FIG. 7 is an explanatory diagram of a Doppler wave obtained when a general Doppler module is pulsed.

FIG. 8 is a structural diagram of an example of a conventional general Doppler module.

[Explanation of symbols]

1 antenna part 2 Doppler module circuit section 11 Dielectric substrate 12 radiator pattern 13 power supply 14 Ground film 21 circuit board 22 Shield case 23 Radio wave output terminal 24 Ground film

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichi Iwai             1-7-14 Shibaura, Minato-ku, Tokyo Co., Ltd.             In Yokowo Ubegiga Device (72) Inventor Heihachi Okano             1-7-14 Shibaura, Minato-ku, Tokyo Co., Ltd.             In Yokowo Ubegiga Device F term (reference) 5J045 AA01 AA02 AA07 AB05 AB06                       DA09 EA07 HA03 MA04 NA07                 5J046 AA01 AA02 AA03 AA07 AB13                       PA07                 5J070 AB01 AB15 AC06 AD01 AE09                       AK40 BA01

Claims (3)

[Claims] 1. A dielectric substrate, a radiator pattern formed on one surface side of the dielectric substrate, and a power supply terminal formed on the other surface of the dielectric substrate connected to the radiator pattern. (2) a circuit board, an oscillator provided on one side of the circuit board for generating a transmission wave, a transmission line for transmitting a transmission wave from the oscillator, and a transmission wave from the oscillator. A circuit component having at least a mixer that mixes a part of the wave with a received wave reflected by an object, and is provided on the other surface side of the circuit board connected to the end side of the transmission line opposite to the oscillator. A Doppler module circuit portion including a radio wave output terminal and a shield case that covers the circuit component provided on the circuit board, and faces the other surface side of the dielectric substrate and the other surface side of the circuit board. Power supply A planar antenna integrated type Doppler module in which a terminal and the radio wave output terminal are connected, and the antenna section and the Doppler module circuit section are joined with a ground film interposed therebetween except for the terminal section. 2. The Doppler module according to claim 1, wherein each of the radio wave output terminal and the power feeding terminal is formed of a strip line of 50Ω. 3. The Doppler module circuit unit includes an oscillator that performs a pulse operation, a first switch circuit that alternately switches a pulse output of the oscillator to two lines having a phase difference of 90 °, and a switch to the two lines. A mixer for mixing a portion of each of the pulse outputs and a received wave reflected by the object of each pulse output, and the output of the mixer is synchronized with the first switch circuit. 3. A Doppler module according to claim 1, further comprising a second switch circuit for separating into a first output and a second output corresponding to the two different phases.