JPH0567916A - Frequency sharing antenna - Google Patents

Abstract

PURPOSE:To realize a frequency sharing antenna sharing a primary radiator using plural frequency bands in which the aperture amplitude distribution is optionally designed for the plural frequency bands. CONSTITUTION:A 2nd mirror surface 1-3 having a frequency selectivity is arranged to the front side of a 1st mirror surface 1-2 and the radiation direction of a radio wave at a frequency band reflected in the 1st mirror surface 1-2 and that at a frequency band reflected in the 2nd mirror surface 1-3 are made equal to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency sharing antenna used for various wireless communications.

[0002]

2. Description of the Related Art In conventional antennas that share a frequency using a primary radiator, the reflector surface is common, so the aperture amplitude distribution obtained by irradiation from the primary radiator differs depending on the frequency band. there were.

[0003]

Therefore, there is a drawback in that the aperture efficiency of the antenna and the edge level of the mirror surface greatly differ depending on the frequency band, and the optimum design cannot be performed simultaneously in a plurality of frequency bands.

It is an object of the present invention to provide a frequency sharing antenna which can arbitrarily design the aperture plane amplitude distribution in a plurality of frequency bands.

[0005]

The present invention relates to a reflector antenna comprising one or more first mirror surfaces and a primary radiator, wherein the primary radiator is a radiator sharing two or more frequency bands. At least one second mirror surface having frequency selectivity is provided on the front surface of at least one mirror surface of the first mirror surface, and the first of the radio waves radiated from the radiator is reflected by the first mirror surface. The first mirror surface and the second mirror surface are determined such that the direction of the radio wave in the frequency band and the direction of the radio wave in the nth frequency band reflected by the nth mirror surface of the second mirror surface are the same direction. It is characterized by being done.

[0006]

The operation of the present invention will be described with reference to FIG. 1 by taking an offset parabolic antenna composed of a main reflecting mirror and a primary radiator as an example.

Reference numeral 1-1 in FIG. 1 denotes a frequency sharing primary radiator, 1
Reference numeral -2 is a main reflecting mirror which is a first mirror surface, 1-3 is a second mirror surface having frequency selectivity, 1-4 is a light beam reflected by the main reflecting mirror, and 1-5 is a mirror surface having frequency selectivity. Are the rays reflected by. In the explanation of this operation, geometrical optics will be explained.

Vectors OM ₁ and OM ₂ are ray vectors from the frequency sharing primary radiator 1-1 toward the main reflecting mirror 1-2 and the mirror surface 1-3 having frequency selectivity.
Main reflecting mirror 1-2 and mirror surface 1-3 having frequency selectivity
Let the ray vectors emitted from the vector be MA ₁ and MA ₂ . In addition, frequency sharing primary radiator 1-1
Share the frequencies f1 and f2, and the mirror surface 1-3 having frequency selectivity transmits the radio wave of the frequency f1 and the frequency f2.
It is a mirror surface that reflects the radio waves of.

At this time, the ray vector OM of the frequency f1 emitted from the frequency sharing primary radiator 1-1 passes through the mirror surface 1-3 having frequency selectivity, is reflected by the main reflecting mirror 1-2, It becomes the vector MA ₁ . On the other hand, the frequency f
The ray vector OM ₂ of No. ₂ is reflected by the mirror surface 1-3 having frequency selectivity and becomes the ray vector MA ₂ . Here, the unit vector of the ray vector OM ₁ is iOM ₁ , the unit vector of the vector OM ₂ is iOM ₂ , and the vector MA.
IMA _{1 1} unit vector, the unit vector of the vector MA ₂ When _{iMA 2, iOM 1 = iOM 2} (1) iMA 1 = under iMA ₂ (2) become conditions, optionally in each frequency The main reflecting mirror 1-2 and the mirror surface 1-3 can be designed.

[0010]

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

FIG. 1 shows the configuration of a frequency sharing antenna using an offset parabolic antenna according to the first embodiment of the present invention. In this first embodiment, the main reflecting mirror 1- which is the first mirror surface is used.
In an offset parabolic antenna including two and a primary radiator 1-1 that shares two or more frequency bands, a mirror surface 1-3 having frequency selectivity, which is a second mirror surface, is provided on the front surface of the main reflecting mirror 1-2. The two mirror surfaces are provided so that the direction of the radio wave of the first frequency band reflected by the main reflecting mirror 1-2 and the direction of the radio wave of the frequency band reflected by the mirror surface 1-3 are the same. It has been decided.

The operation of this embodiment will be described when the frequency sharing primary radiator 1-1 shares the C band and the Ku band. The mirror surface 1-3 having frequency selectivity is designed to have high-pass characteristics. At this time, the Ku band radio wave is transmitted and the C band radio wave is reflected on the mirror surface 1-3 having frequency selectivity. Therefore, Ku
The main reflecting mirror 1-2 for the band and the mirror surface 1-3 having frequency selectivity for the C band can be arbitrarily determined so as to satisfy the above formulas (1) and (2).

The present invention can be applied to any frequency-selective mirror surface such as the lattice type, cross type, and ring type which have been reported so far as long as frequency selection is possible.
That is, even if the frequency selective mirror surface has any characteristics such as high-pass characteristics, low-pass characteristics, and band-pass characteristics,
The antenna can be designed according to its characteristics. Further, the present invention can be applied to a frequency-sharing primary radiator as long as the frequency-sharing horn, a printed antenna and a horn are arranged side by side and the frequency can be shared.

Next, a second embodiment using a sub-reflecting mirror will be described with reference to FIG. In FIG. 2, reference numeral 2-1 is a frequency sharing primary radiator, 2-2 is a main reflecting mirror, 2-3 is a main reflecting mirror having frequency selectivity corresponding to the second mirror surface, 2-4.
Is a sub-reflecting mirror, and 2-5 is a sub-reflecting mirror having frequency selectivity corresponding to the second mirror surface. In addition, 2-6 shows the light rays reflected by the sub-reflection mirror and the main reflection mirror, and 2-7 shows the light rays reflected by the sub-reflection mirror having the frequency selectivity and the main reflection mirror having the frequency selectivity.

Now, as in the first embodiment, the case where the frequency sharing primary radiator 2-1 shares the C band and the Ku band will be described. Sub-reflecting mirror with frequency selectivity 2-
5 and the main reflecting mirror 2-3 having frequency selectivity are designed to have high-pass characteristics. At this time, in the reflectors 2-3 and 2-5 having frequency selectivity, Ku
Radio waves in the band are transmitted and radio waves in the C band are reflected.

Therefore, for the Ku band, the main reflecting mirror 2-2 and the sub reflecting mirror 2-4 are used, and for the C band, the main reflecting mirror 2-3 and the sub reflecting mirror 2-having frequency selectivity are used.
5 can be arbitrarily determined so as to satisfy the following expressions (3) and (4).

IOM ₁ = iOM ₂ (3) iMA ₁ = iMA ₂ (4) Here, the unit vector of the ray vector OM ₁ is iO
M ₁ , the unit vector of the ray vector OM ₂ is iOM ₂ ,
The unit vector of the ray vector MA ₁ is iMA ₁ and the unit vector of the ray vector MA ₂ is iMA ₂ .

It should be noted that each mirror surface can be similarly designed with a quadric surface or a modified curved surface. Therefore, the aperture plane amplitude distribution can be arbitrarily determined, as in a normal antenna design. Further, the number of mirror surfaces can be designed regardless of the number of mirror surfaces, such as a three-reflection mirror and a four-reflection mirror.

In the above embodiment, the main reflecting mirror 2-2 and the sub-reflecting mirror 2 are also used for the mirror surfaces having frequency selectivity.
Although an example in which it is provided on the entire surface of -4 is shown, the same design can be made when it is provided on the front surface of one of the reflecting mirrors.

The present invention is also applicable to the structure and characteristics of the frequency selective mirror surface and the structure of the frequency sharing primary radiator, as in the first embodiment.

Further, in the first and second embodiments, the case where two frequencies of the C band and the Ku band are shared is shown, but the same design is possible for the three frequency bands and the four frequency bands.

[0022]

As described above, according to the present invention,
It is possible to realize a frequency sharing antenna in which the aperture plane amplitude distribution can be arbitrarily designed in a plurality of frequency bands.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of a second embodiment of the present invention.

[Explanation of symbols]

1-1, 2-1 Frequency sharing primary radiator 1-2, 2-2 Main reflecting mirror 1-3 Specular surface having frequency selectivity 1-4 Light beam reflected by main reflecting mirror 1-5 Having frequency selectivity Rays reflected by specular surface 2-3 Main reflecting mirror having frequency selectivity 2-4 Sub-reflecting mirror 2-5 Sub-reflecting mirror having frequency selectivity 2-6 Rays reflected by sub-reflecting mirror and main reflecting mirror 2 -7 Rays reflected by a sub-reflector having frequency selectivity and a main reflector having frequency selectivity

Claims (1)

[Claims] 1. A reflecting mirror antenna comprising one or more first mirror surfaces and a primary radiator, wherein the primary radiator is a radiator sharing two or more frequency bands, and at least one of the first mirror surfaces is provided. One or more second mirror surfaces having frequency selectivity are provided on the front surface of the mirror surface, and among the radio waves radiated from the radiator, the direction of the radio waves of the first frequency band reflected by the first mirror surface and The frequency in which the first mirror surface and the second mirror surface are determined in the same direction as the direction of the radio wave of the nth frequency band reflected by the nth mirror surface of the second mirror surface. Shared antenna.