JPH042487Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a relatively low-height antenna for measuring the direction of arrival of radio waves in the long wave, medium wave, and short wave bands.

[Conventional technology]

To measure the direction of arrival of radio waves in the long, medium, and short wave bands, rotate a directional antenna in a horizontal plane, measure the strength of the received radio waves, and determine whether the strength is the maximum or minimum value. The direction of arrival of the radio waves is calculated by finding the angle that indicates the angle.

When the incoming radio waves are weak, a directional antenna with high sensitivity must be used, but since highly sensitive antennas are generally large, it has been difficult to miniaturize them for use in vehicles.

A core can be used in the antenna to miniaturize the antenna, but when an antenna coil is wound around the core, inductance increases with conventional winding methods, making it difficult to maintain high efficiency up to the shortwave band. It was hot.

Furthermore, the use of a large core to improve the sensitivity of the antenna not only increases inductance, but also has the disadvantage of decreasing mechanical strength and increasing the cost of the core material.

[Improvements made by this invention]

The present invention connects coils wound around multiple cores in parallel to provide an orthogonal loop antenna that not only has low inductance and high receiving sensitivity, but also has a relatively low antenna height.

〔Example〕

FIG. 1 is a perspective view of the structure of the main parts of the present invention, which includes eight cores and two coils wound around each core.

FIG. 2 is a sectional view of the main parts of the present invention housed in a dome.

In the figure, one loop antenna 1 and the other loop antenna 2 are loop antennas of substantially the same quality and are arranged in substantially perpendicular directions, and send power induced by incoming radio waves to feeders 3 and 4.

Core 1 of magnetic material molded from ferrite material etc.
1, 12, 13, and 14, respectively, with coils 21 and 2.
2, 23, 24, 25, 26, 27, and 28, each core is separated and arranged as shown in the figure, and the connecting wire 31
are connected in parallel to obtain a loop antenna 1 having an inductance smaller than the inductance of each coil.

The cores 11 to 14 described above are used to reduce the size of the coils 21 to 28 by increasing the ability to capture radio waves, and the dimensions of the loop antenna 1 can be reduced.

A loop antenna 2 having substantially the same quality and size as the loop antenna 1 described above is arranged in a cross shape at a substantially right angle in substantially the same plane as the loop antenna 1.

That is, the coils 61, 62, 63, 64, 65, 66, 6 are connected to the cores 51, 52, 53, 54.
7 and 68, and connect them in parallel with the connecting wire 41 so that the induced power of each coil is added, to obtain the loop antenna 2 which has a small inductance compared to each coil, and transfer the induced power to the feeder. Take it from 4.

In the explanation of [prior art], it is said that the direction of arrival is calculated by rotating a directional antenna in a horizontal plane and measuring the strength of the received radio waves. In order to achieve this, two sets of loop antennas are placed at right angles and the induced power is applied to a rapidly rotating goniometer, or the direction of arrival is calculated from the output obtained by time-division switching of the induced power. Detectors have been put into practical use.

This device is described, for example, on pages 159 to 166 of the book Explanation of Electronic Navigation Instruments published by Seizando, September 1973.

That is, instead of rotating one set of loop antennas, two sets of loop antennas arranged orthogonally are used to detect the direction of radio waves, and this device has recently become popular.

The present invention provides an orthogonal loop antenna in which a loop antenna consisting of a core and a coil arranged as shown in FIG. 1 is housed in a dome 10 made of plastic material or the like as illustrated in FIG.

In FIG. 2, cores 12, 14, coil 2
3, 24, 27, 28, a connecting line 31, and a feeder 3 are side views of members with the same numbers in FIG. 1, and correspond to half of the loop antenna 1.

The base 7 is made of plastic material or aluminum, and includes support parts 8 and 9 made of stay roll material or plastic material for supporting the cores 12, 14, coils 23, 24, 27, 28, and a dome. Fix 10.

A base 7 is mounted on the roof of a car or the like, and a feeder 3 is pulled into the car to use for direction finding.

The present invention has the structure as explained above, but in the embodiment shown in Fig. 1, a loop antenna is illustrated in which two coils are wound around one core and four coils are connected in parallel. However, it is possible to wind three or more coils around one core, increase the number of cores to 12, etc., increase the size of the core, and reduce the number of cores in loop antennas 1 and 2 to 2. You can change what you do.

According to experiments by the inventors, cores 11, 12, and 13 and 14, and the inductance of the loop antenna 1 in which all the coils are connected in parallel by the connecting wire 31 is approximately 0.5 microhenry, and it is possible to obtain reception sensitivity close to that of a hollow circular loop antenna with a diameter of 1 m. did it.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main parts of the orthogonal loop antenna of the present invention, in which two coils are wound around each of eight cores. FIG. 2 is a sectional view of the main parts of the present invention housed in a dome. 1...One loop antenna, 2...The other loop antenna, 11, 12, 13, 14, 51,
52, 53, 54... multiple cores, 21, 2
2, 23, 24, 25, 26, 27, 28, 6
1, 62, 63, 64, 65, 66, 67, 68
...Multiple coils, 31, 41...Connection wire, 3,
4... feeder, 7... base, 8, 9... support section, 10... dome.

Claims (1)

[Scope of utility model registration request] A plurality of coils 21, 22, 23, 24, 25, 2 wound around a plurality of cores 11, 12, 13, 14
6, 27, 28 are connected in parallel by a connecting wire 31, and a plurality of cores 51, 52, 53, 5 are arranged almost at right angles thereto.
Multiple coils 61, 62, 63, 6 wound around 4
The other loop antenna 2, in which 4, 65, 66, 67, and 68 are connected in parallel by a connecting wire 41, is housed in a dome 10 made of an insulating material such as plastic material, and is induced by feeders 3 and 4. An orthogonal loop antenna that uses multiple cores and coils to extract power.