JPH0399288A - Doppler radar module - Google Patents

Abstract

PURPOSE:To make an apparatus small in size and to reduce the cost thereof without turning the degree of electromagnetic coupling to be lower than usual, by disposing a strip line for electromagnetic coupling between transmission and reception antennas. CONSTITUTION:A Gunn diode H oscillates and its power is emitted from a batch antenna A for transmission. A part of the power excites the whole of a strip line B for electromagnetic coupling which overlaps with the opposite position of the antenna A, and the line B operates as a resonator. Then a strong electromagnetic field is generated and it reaches a batch antenna CA for reception which overlaps with the opposite position of the line B. Thus a reference signal as a local source from the antenna A to the antenna CA reaches the latter. Meanwhile, another signal emitted from the antenna A strikes on some object and turns to be a reflection signal of which the frequency is shifted by a Doppler effect, and it is received by the antenna CA. These reference and reflection signals flows into a Schottky diode I from the antenna CA and a difference component DELTAf of frequencies is obtained by this diode I. Then it is outputted from an IF output terminal F and the movement of the object is detected therefrom in an analyzing device or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technique that is effective when applied to a Doppler radar module, and particularly to an electromagnetic coupling technique between transmitting and receiving antennas.

[Prior Art] Automatic doors, speed guns, etc. are equipped with Doppler radar modules for detecting the position of objects.

Regarding this Doppler radar module, for example, Journal of Physics Instrument Science 17
Volume 1984 edition (J, Phys, Sci, Instru
m, Vo117.1984. Pr1nted in G
rsat Brtain).

FIG. 5 shows this Doppler radar module.

In the figure, reference numeral 11 indicates a dielectric substrate, 1 indicates a transmitting patch antenna, 10 indicates a receiving patch antenna placed at a certain distance away from the transmitting batch antenna 1, and 2 indicates a resonator. , 3 is the radial cavity,
4 is the adjustment stub.

5 is a power supply terminal, 6 is a Gunn diode, 7 is a radial short circuit, 8 is a Schottky diode, and 9 is an IF output terminal. The receiving patch antenna 10 receives a reference signal as a local source transmitted from the transmitting patch antenna 1 by power supplied from the Gunn diode 6 as an oscillation source, and a reference signal as a local source transmitted from the transmitting patch antenna 1 and receiving a signal that hits a certain object. Due to the Doppler effect, a reflected signal with a shifted frequency is received, and the movement of the above-mentioned object can be detected from the difference component between these signals.

Here, between the transmitting and receiving patch antennas 1 and 10,
As mentioned above, a certain gap is provided, and this certain gap enables electromagnetic coupling between the transmitting and receiving patch antennas 1 and 10.

[Problems to be Solved by the Invention] However, the Doppler radar module having the above configuration has the following problems.

That is, when the positional relationship between the transmitting and receiving antennas 1 and 10 is shifted in the vertical direction in the figure, such as the transmitting antenna 1a and the receiving antenna 10, as shown in FIG. ), the degree of electromagnetic coupling becomes small and the efficiency as a local source decreases (if there is no opposing overlap part As shown in FIGS. 5 and 6, the transmitting and receiving antennas 1 and 10 must be placed facing each other without shifting in the vertical direction in the figures, which poses a problem in that layout is restricted and the packaging density is reduced. There is.

In addition, in automatic doors, etc., it is necessary to form an array of patch antennas in order to give the transmitting and receiving antennas a certain range of directivity. Since they must be arranged one-on-one, the equipment becomes larger and costs increase.
On the other hand, in order to reduce the size and cost of the device, for example,
When one transmitting antenna and two receiving antennas are used, the transmitting antenna 1a must be placed so as to overlap both receiving antennas 10 and 10a, as shown in FIG. First, as mentioned above, the degree of electromagnetic coupling ends up decreasing, resulting in a problem that the efficiency as a local source decreases.

Furthermore, in the conventional Doppler radar module, parasitic waves (noise) consisting of unnecessary frequency components other than the fundamental wave of the oscillation source may be received by the receiving antenna 10, which may cause malfunction.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a Doppler radar module that has an increased degree of freedom in layout and an improved packaging density without lowering the degree of electromagnetic coupling compared to the conventional one. It is said that

Another object of the present invention is to provide a Doppler radar module that can be made smaller and lower in cost without lowering the degree of electromagnetic coupling compared to the conventional case when transmitting and receiving antennas are arranged in an array.

Another object of the present invention is to provide a Doppler radar module in which parasitic waves other than the fundamental wave are blocked and malfunctions can be prevented.

[Means for Solving the Problems] Representative inventions disclosed in this volume are summarized as follows.

That is, it is equipped with a transmitting and receiving antenna, and the receiving antenna receives a reference signal as a local source transmitted from the transmitting antenna, and a reflected signal transmitted from the transmitting antenna and having a frequency shifted due to the Doppler effect when it hits a certain object, In a Doppler radar module configured to obtain difference components of these signals, an electromagnetic coupling strip line is arranged between the transmitting antenna and the receiving antenna.

[Operation] According to the above means, since the electromagnetic coupling strip line is arranged between the transmitting antenna and the receiving antenna, even if the transmitting and receiving antennas are arranged at arbitrary positions and shifted from each other, the electromagnetic coupling strip line and If the transmitting and receiving antennas are arranged so that they overlap each other, the electromagnetic coupling stripline is excited by the power from the transmitting antenna, acts as a resonator, and generates a strong electromagnetic field, which is transmitted to the receiving antenna. The above-mentioned objective of increasing the degree of freedom in layout and improving the packaging density without lowering the degree of electromagnetic coupling compared to the conventional one can be achieved by the effect of being able to send the antenna to the semiconductor device.

Similarly, when arranging transmitting and receiving antennas, even if the numbers of transmitting and receiving antennas do not match each other, the electromagnetic coupling strip lines and the transmitting and receiving antennas should be arranged so that they overlap each other. For example, the electromagnetic coupling strip line is excited by the power from the transmitting antenna, acts as a resonator, generates a strong electromagnetic field, and can send this electromagnetic field to the receiving antenna. The above objectives of reducing the size and cost of the device can be achieved without any compromise.

Further, the electromagnetic coupling strip line acts as a resonator, increases f/f, =Q, and can block parasitic waves other than the fundamental wave, thereby achieving the above-mentioned purpose of preventing malfunctions.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a Doppler radar module according to the present invention. The outline is as follows.

In the same figure, the reference numeral indicates a dielectric substrate made of ceramic or Teflon, for example, and on this dielectric substrate there is a transmitting patch antenna A and a receiving batch antenna C.
A etc. are placed there. The receiving patch antenna CA is not placed in a position opposite to the transmitting patch antenna A, and there is no overlapping part facing the transmitting patch antenna A (overlapping part in the vertical direction in the figure with respect to the transmitting patch antenna A). , a first antenna is connected between the transmitting patch antenna A and the receiving patch antenna CA.
As shown in Fig. 2, the receiving patch antenna C
An electromagnetic coupling strip line B is arranged, which has an overlapping portion facing A and transmitting patch antenna A, that is, located at a position facing each of receiving patch antenna CA and transmitting patch antenna Δ. The patch antenna A, CA and the electromagnetic coupling strip line B are made of, for example, Cu.

Here, when a predetermined voltage is applied to the Gunn diode H from the power supply terminal E, the Gunn diode H oscillates, and the power is emitted from the transmitting patch antenna A. A part of the power transmitted from the transmitting patch antenna A excites the entire electromagnetic coupling strip line B that overlaps the position opposite to the transmitting patch antenna A, and the electromagnetic coupling strip line B acts as a resonator. Start working. Then, a strong electromagnetic field is generated, and this electromagnetic field reaches the receiving patch antenna CA that overlaps the position opposite to the electromagnetic coupling strip line B, and from the transmitting patch antenna A to the receiving patch antenna CA. A reference signal as a local source will be reached.

On the other hand, another signal emitted from the transmitting patch antenna A hits a certain object and becomes a reflected signal with a shifted frequency due to the Doppler effect, which is received by the receiving patch antenna CA. These reference signals and reflected signals flow into the Schottky diode E from the receiving patch antenna CA, and after a frequency difference component Δf is obtained by the Schottky diode I, the signal is output from the IP output terminal F, and is analyzed (not shown). It is now possible to detect the movement of the above-mentioned object using a device or the like.

Note that the reference numerals in FIG. 1 indicate high frequency blocking filters, G indicates adjustment stubs, and J indicates load resistance.

In this way, even if the transmitting and receiving antennas A and CA are arranged at arbitrary positions and shifted from each other (even if there is no overlapping part where the transmitting patch antenna A and the receiving patch antenna CA face each other as in this embodiment), Since the electromagnetic coupling strip line B and the transmitting and receiving antennas A and CA are configured to overlap with each other, it is possible for the reference signal as a local source to reach from the transmitting patch antenna A to the receiving patch antenna CA. Therefore, the transmitting/receiving antenna can be placed at any position, increasing the degree of freedom in layout.

The packaging density is being improved. Moreover,
Since the degree of electromagnetic coupling is not lower than before, it is highly efficient as a local source and can perform the desired functions.

In addition, the electromagnetic coupling strip line acts as a resonator as described above and can increase f/f, =Q, so it can block parasitic waves having frequencies other than the fundamental wave.
It is also possible to prevent malfunctions.

Next, a modified example in which the receiving patch antennas are arrayed in order to give the receiving patch antennas a certain range of directivity will be described with reference to FIG.

In this modification, one transmitting patch antenna A
and two receiving patch antennas CA.

CB (indicated by a phantom line) is used, and the receiving patch antenna CB on the upper side in the figure is placed at a position substantially opposite to the transmitting patch antenna A, but the receiving patch antenna CB on the lower side in the figure The CA is not placed at a position opposite to the transmitting patch antenna A, and there is no overlapping portion facing the transmitting patch antenna A.

Even with this configuration, the electromagnetic coupling strip line B and the transmitting/receiving antennas A, CA,
Since the antennas CB and CB overlap each other, it is possible for the reference signal as a local source to reach from the transmitting patch antenna A to the receiving patch antennas CA and CB. Needless to say, this increases the flexibility of the layout and improves the packaging density.In addition, the transmitting patch antenna and the receiving patch antenna are no longer connected as in the past. the same number of 1:1
Since there is no need to adapt the transmitter/receiver antenna A to the transmitter/receiver antenna A, it is possible to reduce the size and cost of the device.

Even if the CAs are arranged at arbitrary positions and shifted from each other, the degree of electromagnetic coupling will not be reduced as in the conventional case, so the efficiency as a local source is high and the desired function can be achieved.

Specifically, as shown in FIG. 3, the overlapping portions X of the electromagnetic coupling strip line B and the transmitting/receiving antennas A, CA, and CB are λ/4×n (λ is oscillation frequency (n is an integer).

According to the Doppler radar module configured in this way, the following effects can be obtained.

That is, since the electromagnetic coupling strip line B is placed between the transmitting patch antenna A and the receiving patch antenna CA (CB), the transmitting and receiving patch antennas A, CA
Even if (CB) are placed at arbitrary positions and shifted from each other,
If the electromagnetic coupling strip line B and the transmitting/receiving patch antennas A and CA (CB) are arranged so as to overlap each other, the electromagnetic coupling strip line B is excited by the power from the transmitting patch antenna A. , acts as a resonator, generates a strong electromagnetic field, and can send this electromagnetic field to the receiving patch antenna CA (CB), which allows for greater flexibility in layout without lowering the degree of electromagnetic coupling compared to conventional methods. This makes it possible to improve the packaging density.

Similarly, when arranging transmitting and receiving patch antennas, even if the numbers of the transmitting patch antenna A and the receiving patch antennas CA and CB do not match each other, the electromagnetic coupling strip line B and the transmitting and receiving patch If antennas A, CA, and CB are arranged so as to overlap with each other, the electromagnetic coupling strip line B is excited by the power from the transmitting batch antenna A, acts as a resonator, and generates a strong electromagnetic field. By being able to send this electromagnetic field to the receiving patch antennas CA and CB, it is possible to reduce the size and cost of the device without lowering the degree of electromagnetic coupling compared to before. It becomes possible.

Furthermore, the electromagnetic coupling strip line acts as a resonator, increases f/f, =Q, and can block parasitic waves other than the fundamental wave, thereby making it possible to prevent malfunctions.

FIG. 4 shows another embodiment of the Doppler radar module according to the present invention.

The difference between the Doppler radar module of this embodiment and the previous embodiment is that there is an electromagnetic coupling strip line BB between the transmitting batch antenna A and the receiving batch antenna C.
, a plurality of BB-BBs are arranged in a band-pass filter shape,
This is the point designated as strip line B for electromagnetic coupling.

Needless to say, even with this configuration, the same effect as in the previous embodiment can be obtained.Furthermore, since the electromagnetic coupling strip line B is arranged like a band-pass filter, A new effect can be expected in that parasitic waves can be further blocked than in the previous embodiment.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, in the modification of the above embodiment, there is one transmitting batch antenna and two receiving patch antennas, but the number of transmitting and receiving batch antennas is not limited to the above.

Note that the Doppler radar module of the present invention can also be used for satellite broadcasting, and for example, the present electromagnetic coupling strip line can be interposed at the local power injection site of a DBS converter.

[Effects of the Invention] The effects obtained by typical inventions disclosed in this application are briefly explained below.

That is, it is equipped with a transmitting/receiving antenna, and the receiving antenna receives a reference signal as a local source transmitted from the transmitting antenna, and a reflected signal transmitted from the transmitting antenna, which hits a certain object and has a frequency shift due to the Doppler effect. In the Doppler radar module configured to obtain the difference component of these signals, an electromagnetic coupling strip line is arranged between the transmitting antenna and the receiving antenna, so that the transmitting and receiving antennas can be arranged at arbitrary positions and shifted from each other. However, if the electromagnetic coupling strip line and the transmitting/receiving antenna are arranged so as to overlap with each other, the electromagnetic coupling strip line is excited by the power from the transmitting antenna and acts as a resonator. This field can then be sent to a receiving antenna. As a result, the degree of freedom in layout can be increased without reducing the degree of electromagnetic coupling compared to the conventional one, and it is possible to improve the packaging density.

Similarly, when arranging transmitting and receiving antennas, even if the numbers of transmitting and receiving antennas do not match each other, the electromagnetic coupling strip lines and the transmitting and receiving antennas should be arranged so that they overlap each other. For example, the electromagnetic coupling stripline is excited by the power from the transmitting antenna, acts as a resonator, and can transmit this electromagnetic field to the receiving antenna without producing a strong electromagnetic field. As a result, it is possible to reduce the size and cost of the device without lowering the degree of electromagnetic coupling compared to before.

In addition, the electromagnetic coupling strip line acts as a resonator, increases f/f, =Q, and can block parasitic waves other than the fundamental wave. As a result, it is also possible to prevent malfunctions.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a Doppler radar module according to the present invention. Figure 2 is an enlarged perspective view of the transmitting/receiving antenna and the electromagnetic coupling strip line in Figure 1, Figure 3 is a diagram for explaining the overlap between the transmitting/receiving antenna and the electromagnetic coupling strip line, and Figure 4 is the main A schematic configuration diagram of another embodiment of the Doppler radar module according to the invention. FIG. 5 is a schematic configuration diagram of a Doppler radar module according to the prior art. FIG. 6 is a diagram for explaining the positional relationship of transmitting and receiving antennas of a Doppler radar module according to the prior art. A: Transmitting antenna, B, BB: Strip line for electromagnetic coupling, C, CA, CB: Receiving antenna. fig. fig. ca.

Claims (3)

[Claims] 1. A transmitting and receiving antenna is provided, and the receiving antenna receives a reference signal as a local source transmitted from the transmitting antenna and a reflected signal transmitted from the transmitting antenna and having a frequency shifted due to the Doppler effect due to the Doppler effect. What is claimed is: 1. A Doppler radar module configured to obtain a difference component, characterized in that an electromagnetic coupling strip line is disposed between the transmitting antenna and the receiving antenna. 2. The length of the facing overlap between the electromagnetic coupling strip line and the transmitting/receiving antenna is λ/4×n(
2. The Doppler radar module according to claim 1, wherein λ is an oscillation frequency and n is an integer. 3. 3. The Doppler radar module according to claim 1, wherein a plurality of said electromagnetic coupling strip lines are arranged in the shape of a band-pass filter.