JPS617706A - Circularly polarized wave antenna - Google Patents

Abstract

PURPOSE:To spatially generate a circularly polarized wave so as to obtain a circularly polarized wave having a wide band axial ratio characteristic to two separate specific frequencies, by performing equal-amplitude electricity supply of 90 deg. phase difference to each feeding point of two micro-strip type antennas which are arranged in two directions spatially intersecting with each other at right angles. CONSTITUTION:Micro-strip type antennas 1a and 1b are arranged in directions spatially intersecting with each other at right angles on a dielectric 3 constituting a circularly polarized wave antenna and equal-amplitude electricity supply of 90 deg. phase difference is made to the feeding points 2a and 2b of the antennas 1a and 1b from a hybrid circuit 5. Circularly polarized wave components of frequencies f1 and f2 intersecting at right angles are respectively radiated from the antennas 1a and 1b. Then a circularly polarized wave is spatially generated by means of the antennas 1a and 1b so as to radiate a circularly polarized wave having a wide band axial ratio characteristic to the separate specific frequencies f1 and f2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses two microstrip type antennas.
It relates to an antenna that generates circularly polarized waves at different frequencies.

A common way to generate circularly polarized waves is by using a conventional microstrip antenna.

There is a two-point feeding type as shown in FIG. 1 and a one-point feeding type as shown in FIG. In the case shown in Figure 1, the dielectric plate 3
A conductive pattern i having a shape that resonates at a specific frequency and has radiation characteristics is printed on one side of the base plate, and a conductive base plate 4 is provided on the other side. When the conductor pattern 1 is circular as shown in the figure, two points are equidistant from the center with an opening angle of 90 degrees.
The two feeding points 2a and 2b are connected to the hybrid circuit 5,
Since the power is fed with a phase difference of 90 degrees from each other, modes with a phase difference of 90 degrees are generated in two orthogonal directions in the conductor pattern 1, generating spatially circularly polarized waves. Note that the hybrid circuit 5 has an input point 7. A load 6 is coupled.

In the case of FIG. 2, if the degenerate separation element 8 is loaded on the conductor pattern 1, two
Two modes are generated to generate spatially circularly polarized waves. By the way, the microstrip antenna has a drawback of having a narrow band due to its high Q during resonance. Therefore, as a method of lowering Q in order to widen the band, there is a method of lowering the dielectric constant of the dielectric plate 3 or increasing the thickness of the dielectric plate. Another method is to widen the band by installing an excited conductor plate of an appropriate shape at an appropriate position in front of the excited conductor pattern 1. These methods have problems such as generation of higher-order modes and complicated shapes. In contrast, the microstrip antenna shown in Figure 2 has a degenerate 2
Since the phase difference between two orthogonal modes is used, the input impedance band is relatively wide, but the axial ratio band is narrow. This is how microstrip antennas work.

It has been difficult to generate circularly polarized waves at two relatively distant frequencies.

The present invention has been developed in consideration of these conventional problems.

At two specific frequencies, microstrip antennas that are excited in directions spatially 90 degrees apart are spaced 90 degrees apart from each other.
Two microstrip antennas are arranged in different directions, and one of the microstrip antennas is fed with a phase difference of 90 degrees.
This type of circularly polarized wave is provided without narrowing the axial ratio band by generating circularly polarized wave in the frequency, and will be explained in detail below with reference to the drawings.

FIG. 3 shows a microstrip antenna excited at two frequencies, one conductor pattern 1 having two frequencies f1. h
Each of them is excited in one direction orthogonal to the other. Now install the feeding point 2 at a randomly selected position, and set the conductor pattern 1 in a shape that resonates at two specific frequencies.
For example, in the case of a rectangle as shown in the figure, its -side A, ! l:
It is known that when B is determined, radiation characteristics with orthogonal polarization planes can be obtained at each frequency f, , f2.

The present invention utilizes the two-frequency f1. Two microstrip antennas excited by f2 are spatially spaced at 9
They are arranged in 0 degree different directions.

FIG. 4 shows an example of this. The microstrip type antennas la and lb of the present invention are arranged in spatially orthogonal directions, and equal amplitude power is fed to each feed point 2a and 2b with a phase difference of 90 degrees. This consists of two microstrip antennas 1a, 1. b
Orthogonal polarized components are radiated from the feeding point 2a.

2b, for example, a phase difference of 90
By feeding electricity with equal amplitude of 100°, circularly polarized waves are generated spatially.

By having the above configuration, it is possible to specify a relatively separate area. two. It is possible to generate a circularly polarized wave having a frequency of Km and a broadband axial characteristic.

[Brief explanation of the drawing]

Figure 1 shows a two-point feeding microstrip circularly polarized antenna, Figure 2 shows a single point feeding microstrip circularly polarized antenna, and Figure 3 shows a microstrip antenna excited at two frequencies. It is a circularly polarized antenna consisting of a type antenna. Pigeon...conductor pattern, 2...feeding point, 3...dielectric plate, 4...conductor ground plate, 5...no-brit circuit. 6...Load, 7...Power supply point

Claims (1)

[Claims] Two microstrip antennas that resonate at two frequencies and have a spatial direction difference of 90 degrees in the mode direction at the two frequencies are arranged in spatially 90 degrees different directions, and each A circularly polarized antenna characterized by feeding power by giving a phase difference of 90 degrees to a strip antenna.