JP3266466B2 - Helical antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-segment helical antenna having circular polarization suitable for mobile satellite communications.

[0002]

2. Description of the Related Art In recent years, a new mobile communication system using a satellite has been proposed. To achieve this, it is important to reduce the size and economy of mobile station antennas installed in automobiles and portable devices. Is an important task.

[0003] Therefore, there have been proposals for simplifying a satellite tracking mechanism of a mobile station antenna to achieve miniaturization and economy. As an antenna that simplifies the satellite tracking mechanism, there is an antenna that emits a circularly polarized conical beam having a symmetric directivity with respect to the zenith axis and sets the radiation direction to the elevation angle of the satellite.

[0004] As an example of such an antenna, a so-called so-called "wire" in which four conductive wires are spirally wound within one rotation and a standing wave is put on the wire to radiate a radio wave to a feeding point side.
Backfire type helical antenna (hereinafter referred to as helical antenna) is a US-based Microwave Helix Design /
Known by the author CC Kilus / (1970).
However, a conventional helical antenna that realizes a circularly polarized conical beam has a complicated feeding structure.

In order to solve the conventional problems, the present invention provides a four-segment helical antenna whose configuration can be simplified by appropriately configuring a helical antenna that is a circularly polarized antenna. It is intended to be.

[0006]

According to the present invention, the above objects are achieved by the invention as set forth in the appended claims. That is, the present invention relates to a four-segment helical antenna in which two sets of radiating elements composed of conductor wires are alternately arranged, spirally formed at the same pitch angle and in the same direction, and fed in parallel to both radiating elements. One set of radiating elements consists of a first coaxial line and a first conductor, and the other set of radiating elements is a second
At the one end of the antenna, the center conductor of the first coaxial line and the first conductor are coupled at a high frequency, and the outer conductor of the first coaxial line is opened to open the first coaxial line. A first power supply point is disposed, and crosses the power supply point to couple the center conductor of the second coaxial line and the second conductor at high frequency and to provide a second power supply point.
The second feed point is arranged with the outer conductor of the coaxial line of the antenna open, the third coaxial line is provided at the other end of the antenna, and the center conductor of the first coaxial line and the center conductor of the second coaxial line are provided. And the third
High frequency coupling with the center conductor of the
The second conductor, the second conductor, the outer conductor of the first coaxial line, the outer conductor of the second coaxial line, and the outer conductor of the third coaxial line are coupled at a high frequency, and a terminal is connected to the third coaxial line. The transmission and reception signals are extracted.

That is, the present invention provides a four-wire fractional-winding type in which two sets of radiating elements composed of conductor wires are alternately arranged, spirally formed at the same pitch angle and in the same direction, and fed in parallel to both radiating elements. The helical antenna has a first feeding point 51 and a second feeding point 52 at the tip of the antenna as shown in an example in FIG. 1 and has a transmitting / receiving signal extracting terminal 61 by the third coaxial line 2 at the other end. One of the two pairs of conductor lines of the antenna radiating portion is a first coaxial line 31.
And a second coaxial line 32, and the other conductor line is formed of a first conductor 41 and a second conductor 42, and a first power supply point 51
, The center conductor of the conductor wire composed of the first coaxial line 31 and the first conductor 41 are coupled at a high frequency (the outer conductor of the conductor wire is open at the feeding point 51), and the other end of the first conductor is connected to the first conductor. The conductor 41 and the outer conductor of the first coaxial line 31 are coupled at a high frequency. Similarly, at the second feed point 52, the center conductor of the conductor composed of the second coaxial line 32 and the second conductor 42 are connected at a high frequency. (The outer conductor of the conductor wire is 5
2, the second conductor 42 and the outer conductor of the second coaxial line 32 are coupled at a high frequency at the other end, and the inner conductors of the coaxial line 31 and the coaxial line 32 are The outer conductors are connected at high frequencies.

[0008]

FIG. 1 shows the configuration of the present invention. In a helical antenna, circular polarization can be obtained by selecting an appropriate size and shape. At this time, as parameters for generating the circularly polarized conical beam, shape parameters such as a diameter, a pitch, and a winding angle of the support 1 of the insulating cylinder (for example, made of glass fiber reinforced polyester) are dominant.

In the present invention, as shown in FIG. 1, one of the two sets of conductors is composed of a first coaxial line 31 and a second coaxial line 32, and the other conductor is composed of a first conductor 41 and a first coaxial line. 2 conductor 42
The first coaxial line 31 and the second coaxial line 32 have a symmetrical structure, and the first coaxial line 31 and the second coaxial line 32 intersect at the first power supply point 51 and the second power supply point 52, so that the power is supplied from the third coaxial line 2. The high-frequency current that has flowed through the center conductor of the third coaxial line 2 with the high-frequency current to be transmitted ends at the helical winding end point, that is, at the transmission / reception signal extraction terminal 61, where the first coaxial line 31 and the second coaxial line 32 The first coaxial cable 31 and the second coaxial cable 32 flow in the other direction at the first power supply point 51 and the second power supply point 52 as they are. The high-frequency currents having the same magnitude and flowing in opposite directions flowing inside the outer conductor of the first coaxial line 31 and the second coaxial line 32
Flows outside of the outer conductor. At this time, if both the first conductor 41 and the second conductor 42 are coupled to the outer conductor 4 of the third coaxial cable 2 at the transmission / reception signal extraction terminal 61 at high frequencies, the respective high-frequency currents have the same magnitude. Since it is in the opposite direction, it is terminated without flowing on the conductor thereafter, so that the high-frequency current apparently flows only in the necessary radiating portion.

According to the above embodiment, a circularly-polarized conical beam having radiation directivity, an example of which is shown in FIG. 2, is obtained.

As described above, the center conductor of the first coaxial cable 31 serving as a radiating element is coupled to the first conducting wire 41 serving as a radiating element at a high frequency at the feeding point 51. Similarly, the second coaxial line 32 serving as a radiating element is coupled at a second feeding point 52 to the second conductor 42 serving as a radiating element at a high frequency. The four radiating elements (two sets of radiating elements) of the first coaxial line 31, the second coaxial line 32, the first conducting wire 41, and the second conducting wire 42 are connected to the first feeding point 51 and the second feeding point 51. Intersect at the feeding point 52.

[0012] Here, 4 is wound around a cylindrical support 1.
Although the description has been given of the helical antenna having a number of line segments, a polygonal pillar, a polygonal pyramid, and a body without a support (the first coaxial line 31, the second coaxial line 32 and the first conductive wire 41, the second
It is needless to say that the same can be said for the case where the conductive wire 42 is rigid (for example, when a semi-rigid conductor wire material is used).

[0013]

As described above, according to the configuration and method of the present invention, a four-segment circularly wound helical antenna for circular polarization can be appropriately configured using the coaxial wires 31 and 32 and the conductors 41 and 42. There is an advantage that a simple power supply system can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram of a helical antenna showing an embodiment of the present invention.

FIG. 2 is a diagram showing actually measured values of radiation directivity on a plane including an antenna axis according to an embodiment of the present invention.

[Explanation of symbols]

1: Supporting body 2: Third coaxial line 3: Central conductor of third coaxial line 4: Outer conductor of third coaxial line 5: Insulator of third coaxial line 31: First radiating element Coaxial line 32: second coaxial line serving as a radiating element 41: first conductive line serving as a radiating element 42: second conductive line serving as a radiating element 51: first feeding point 52: second feeding point 61: transmission / reception Signal extraction terminal

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-274904 (JP, A) JP-A-4-134906 (JP, A) JP-A-3-74906 (JP, A) JP-A-6-1994 326511 (JP, A) US Patent 4,608,574 (US, A) Noriyoshi Terada, Kenichi Kagoshima, Mobile Satellite Communication Conical Beam 2-Wound Helical Antenna, IEICE Technical Report, Japan, Japan Electronics Information and Communication Society, July 9, 1991, p. 21 (58) Field surveyed (Int.Cl. ⁷ , DB name) H01Q 11/08

Claims (1)

(57) [Claims] 1. A four-segment helical antenna in which two sets of radiating elements composed of conductor wires are alternately arranged and spirally formed at the same pitch angle and in the same direction to feed power in parallel to both radiating elements. One set of radiating elements comprises a first coaxial line and a first conductive line, and another set of radiating elements comprises a second coaxial line and a second conductive line. Center conductor and first
And a first feeding point is arranged with the outer conductor of the first coaxial line in an open state, and intersects with the first feeding point and the center conductor of the second coaxial line and the second conducting wire. And a second feed point is arranged with the outer conductor of the second coaxial line open, and a third coaxial line is provided at the other end of the antenna, and the center of the first coaxial line is provided. The conductor, the center conductor of the second coaxial line, and the center conductor of the third coaxial line are coupled at a high frequency, and the first conductor, the second conductor, the outer conductor of the first coaxial line, and the second conductor are connected to each other. A helical antenna, characterized in that the outer conductor of the coaxial line and the outer conductor of the third coaxial line are coupled at a high frequency, and a terminal is provided on the third coaxial line to extract a transmission / reception signal.