JPH0513584B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antenna device for radio direction finding that detects the arrival direction of radio waves using a plurality of plate antennas.

[Prior art]

A method of detecting the direction of arrival of radio waves using the azimuth component in the output obtained by a plate antenna having a plane parallel to the plane on which the direction of arrival of the radio waves to be detected is arranged is disclosed in Japanese Patent Laid-Open No. 147666/1983. , Japanese Patent Publication No. 1983-
108404 etc.

These are configured by alternately switching each vertex of a plurality of orthogonally arranged band-like antennas for signal extraction and termination, or by stacking a plurality of plate antennas vertically and orthogonally arranged and performing the same switching as above. It has a similar structure.

[Problem to be solved by the invention]

In general, among the measurement errors in radio direction finders, the site error caused by the influence of other disturbing objects decreases as the outside diameter of the antenna arrangement increases; When the antenna frequency is high, such as an antenna using the cyclic switching phase modulation method, each antenna can be arranged at a large interval and have a large outer diameter, so that each antenna can absorb radiation waves from disturbing objects. It is disclosed in pages 180 to 182 of "Radio Direction Measuring Device" published by Corona Publishing in August 1955 that it is desirable to provide as large a difference as possible in the distance at which the signal is received.

Therefore, in the conventional type described above, when configured for use in the ultrashort wave band, the length of the plate antenna itself cannot be longer than the receiving wavelength, so the outer diameter of the plate antenna cannot be longer than the wavelength of the radio waves to be detected. Since it cannot be expanded, there is a disadvantage that there is a limit to reducing this site error.

[Means to solve the problem]

In this invention, each antenna is formed as a plate-shaped antenna parallel to the ground plane at intervals on a ground plane on which three or more antennas as described above are arranged, and the center of the arrangement is They are set up in different directions when viewed from
In a radio direction finding antenna device that obtains a detection signal having an azimuth component based on the direction of arrival of radio waves by a signal obtained by switching the output of the outer end of each antenna in a predetermined order, the plane of each antenna described above is Antenna means formed in a line-symmetrical shape and provided with a terminating resistor to the ground plane at the inner end of each antenna, and the line-symmetrical lines of each antenna are arranged in different directions radially from the center of the antenna arrangement. The above problem can be solved by positioning the antenna on a radial line, positioning each inner end at a point away from the center, and providing antenna arrangement means for positioning adjacent antennas apart from each other. This is what I did.

〔Example〕

An embodiment of a 250MHz to 500MHz direction finding antenna device will be described with reference to the drawings.

In the figure, antennas 11 to 14 are plate-shaped antennas installed on radial lines a, b, c, and d at 90° intervals. Aluminum plates are arranged so that their diagonal lines coincide with radial lines.

The terminating resistors 21 to 24 are resistors corresponding to the terminating impedance described later, and are connected to the inner vertex points of each antenna 11 to 14, that is, to the terminating points 25 to 28, as shown in FIG. 7a, for example. The core wire side of the receiving side is used as a terminal, the shield side is connected to the grounding board 10 described later, and a non-inductive resistor is connected between the core wire on the plug side of the connector and the shield side, that is, a coaxial type non-conductor. It is electrically connected to a grounding board 10 (described later) using a reflective terminator.

The signal extraction terminals 61 to 64 are connected to each antenna 11 to
It is a terminal provided at the outer vertex point of 14, that is, the extraction point.For example, the receiving side of a coaxial cable connector is used as a terminal, and the core wire side is connected to the extraction point as shown in Figure 7a. Connect the shield side to the grounding board 10 described later, and connect the coaxial cable 101 to the plug side.
~104 are connected.

The signal outputs of the signal extraction terminals 61 to 64 are led to respective switching circuits 41 to 44, which will be described later, by signal extraction cables 101 to 104.

A grounding board 10 connects each antenna 1 to incoming radio waves.
A conductor plate that is considered to be substantially electrically grounded when viewed from 1 to 14, for example, an aluminum plate with an outer diameter that is about 2 to 3 times the outer diameter D of the antenna arrangement. supported on the ground or in the air in any suitable manner. Each antenna 11~
The relationship between the height h at which the antenna 14 is supported on the grounding board 10 and the value γ of the terminating resistors 21 to 24 is the impedance terminating resistor at the termination point of the wave impedance between each antenna 11 to 14 and the grounding board 10. For example, each piece of each antenna 11-14 is 12 cm, the distance s between the antennas is 5 cm, and the value γ of the terminating resistors 21-24 is adjusted so that the height h is the value γ. is 50 ohm,
When the impedance of the signal extraction cables 101 to 104 is 50 ohms, the heights of the signal extraction terminals 61 to 64 and the terminal points 25 to 28 are set so that the height h is 2 to 3 cm. .

In this case, the outer diameter D of the antenna arrangement is about 41 cm, and the outer diameter of the grounding board 10 is about 100 cm.

The switching unit 5 is a shield box body that houses switching circuits 41 to 44 described later and a switching signal generation circuit 9 that generates switching signals 9A to 9D, etc., and is a cabinet made of an aluminum plate, for example, and is connected to the grounding board 10. It is connected and fixed on the side opposite to the antennas 11 to 14.

The switching circuits 41 to 44 are diode switching circuits each composed of a diode 7 and a resistor 8 provided in each case, and a commonly provided switch coil 110. Each antenna 11-1 is applied to the input side of each diode 7 by a cable 101-104 by applying a signal 9A-9D between each resistor 8 and a chiyoke coil 110.
The received outputs of antennas 1 and 4 are repeatedly switched and extracted in a predetermined order, for example, in the order of antennas 11, 12, 13, and 14, and then connected to the common output line 1.
11 to obtain a detection signal 111A.

In the above configuration, each antenna 11 to 1
The directivity characteristic of No. 4 is a cardioid type unidirectional directivity as shown in FIG. 4a. Therefore antenna 1
If each of the directional characteristics 1 to 14 is expressed on one side, the directional characteristics 11A to 14A as shown in Fig. 4b are obtained, and the switching signals 9A to 9D are converted into four-phase signals whose phases are sequentially shifted as shown in Fig. 4c. By using a rectangular wave signal of
1a and the antenna 13 in the opposite direction has the minimum output 13a. For example, by Fourier expanding the signal in FIG. Direction finding can be done by methods such as detecting direction by phase points.

[Modification example]

This invention can be implemented in the following modifications.

(1) The number of antennas 11 to 14 should be three at the minimum as shown in Figure 5, and the arrangement outer diameter effect, detection sensitivity,
In order to improve directional accuracy, it is better to provide as many as possible.

(2) If the angular intervals of the radial lines a, b, and c in the direction in which the antennas 11 to 14 are arranged cannot be made equal due to the structure of the device, use appropriate unequal angular intervals to calculate the angles for direction finding. Make it compatible with.

(3) If the positions of the antennas 11 to 14 on the radial line, that is, the distances from the center of the antenna arrangement cannot be made equal due to structural reasons, calculate the angle for direction finding by making them uneven as shown in Figure 6. to correspond to this.

(4) The shape of the plates of the antennas 11 to 14 should be circular, rhombic, even square, etc., so that they are symmetrical to each radial line of each antenna 11 to 14, and also symmetrical to a line orthogonal to the radial line. shape, and each apex angle or edge of the arc is the terminal point of the signal extraction point.

(5) Connect the terminating resistors 21 to 24 between the terminating points 25 to 28 of each antenna 11 to 14 and the grounding board 10 as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, by arranging the plate antennas at intervals, it is possible to increase the outer diameter D of the antenna arrangement. The present invention has the advantage of being able to provide a wireless direction finding antenna device with less error. In the above example, 250MHz~
I mentioned the case of 500MHz, but from 150MHz
Even at 500MHz, it is possible to obtain the minimum signal-to-noise ratio and front-to-back ratio of directional characteristics for a direction finder.

Additionally, by setting each side of each antenna 11 to 14 to approximately 25 cm and spacing between the antennas to approximately 10 cm, it is possible to obtain an antenna device for 30 MHz to 200 MHz, which is tailored to the desired frequency band. .

Signal extraction points 61 to 64 of each antenna 11 to 14
A detection signal similar to that described above can be obtained even with a configuration in which the terminal points 25 to 28 are reversed, but other antennas are arranged in the direction in which the directivity of each antenna 11 to 14 is formed. Therefore, the directivity characteristics are disturbed due to the influence of these factors, making it unsuitable as a direction finding antenna device.

[Brief explanation of the drawing]

Fig. 1 is a plan view, Fig. 2 is a longitudinal sectional view, Fig. 3 is a circuit configuration diagram, Fig. 4 a and b are directional pattern diagrams,
FIG. 4c is a signal waveform diagram of each part, FIGS. 5 and 6 are a plan view of the antenna arrangement, FIG. 7 is a side view of the main part, and FIG. 8 is a sectional view of the main part. 11-14...Antenna, 21-24...Terminal resistor, 25-28...Terminal point, 31-34...Strut, 41-44...Switching circuit, 4, 5...Switcher, 61-64... ...Signal extraction point, 7...Diode, 8...Resistor, 9...Switching signal generation circuit, 10
...Grounding board, 110...Chiyoke coil, 11
1...Output line, 101-104...Signal extraction cable, 11A-14A...Antenna directivity characteristic,
11a to 14a...Output of each antenna, 9A to 9
D... Switching signal, h, h1, h2... Height of the antenna from the grounding board, a to d... Radial line, D...
...Arrangement outer diameter, s...Antenna spacing, α...Arrival direction of radio waves, _θ1 to _θ3 ...Angle spacing of radial lines.

Claims (1)

[Scope of Claims] 1. Each of the antennas is formed as a plate-shaped antenna that is parallel to the ground plane and spaced apart from the ground plane on which three or more antennas are disposed, and the above-mentioned arrangement are provided in different directions as viewed from the center of the antenna, and the output of the outer end of each antenna is switched in a predetermined order to obtain a detection signal having a direction component based on the arrival direction of the radio wave. A detection antenna device, comprising: (a) an antenna means in which the plane of each of the antennas is formed into a line-symmetrical shape, and a terminating resistor for the ground plane is provided at an inner end of each of the antennas; (b) the wire of each of the antennas; A target line is positioned on a radial line arranged in different directions radially from the center, each of the inner ends is positioned at a point outwardly away from the center, and each of the adjacent antennas is positioned and arranged apart from each other. What is claimed is: 1. An antenna device for radio direction finding, characterized in that it comprises an antenna arrangement means. 2. An antenna device for radio direction finding according to claim 1, characterized in that the antenna device is provided with the antenna means for forming each of the antennas into a rectangular plane. 3. The radio direction finding antenna device according to claim 1, further comprising the antenna means for arranging the terminating resistor on the lower side of a grounding board forming the ground plane and connecting it to the inner end. An antenna device for wireless direction finding, characterized in that: 4. The radio direction finding antenna device according to claim 1, comprising the antenna means for connecting the terminating resistor to a space between the grounding board forming the ground plane and the inner end. A wireless direction finding antenna device characterized by: