JPH01277006A - Primary radiator for circularly polarized wave - Google Patents

Abstract

PURPOSE:To obtain an electric signal from the wave of a linearly polarized wave to a probe by changing the wave of a circularly polarized wave led in a waveguide into the wave of the linearly polarized wave when the wave of the circularly polarized wave comes. CONSTITUTION:When a left-handled circularly polarized wave comes directly from the transmission point of the microwave of a broadcasting satellite, etc., or after reflected by a parabola reflection mirror to a conical horn 6, the wave is led in the waveguide through the horn 6. The wave of the led-in circularly polarized wave passes through the existential position of a probe 7, arrives at a reflecting plate 9, the reflecting plate 9 reflects, at its front end 9a, components of the wave of the circularly polarized wave which are parallel to the face direction of a reflecting plate 9 and permits vertical components to proceed to the side of a reflecting face 5a. In the position of the probe 7, the wave of the led-in circularly polarized wave becomes the wave of the linearly polarized wave which oscillates in the direction parallel to the direction of the probe 7. The wave of the linearly polarized wave vibrates the probe 7 and the electric signal is generated in the probe 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a primary radiator for circularly polarized waves that receives circularly polarized radio waves and converts them into electrical signals.

[Conventional technology]

Inside a waveguide that is open at one end and closed at the other end, the length of approximately λ (λ is the input A λ74 retardation plate with a wavelength of the incoming radio wave) is placed, and a probe is provided behind the retardation plate so that an electrical signal is excited by linearly polarized radio waves.

[Problem to be solved by the invention]

This conventional primary radiator for circularly polarized waves requires extra space to arrange a λ74 retardation plate with a length of approximately λ in front of the probe inside the waveguide. There was a problem in that the tube had to be made longer, which prevented the primary radiator from being made smaller.

The present invention has been made in view of the above points, and its purpose is to convert circularly polarized radio waves into linearly polarized radio waves, and to transmit electrical signals from the linearly polarized radio waves to a probe. Even if it is made in this way, there is no need for any space in front of the probe to place a member for conversion as in the prior art, and the form can be made smaller and bulkier. It is an object of the present invention to provide a primary radiator for circularly polarized waves that can be used for circularly polarized waves.

[Means to solve problems]

In order to achieve the above object, the present invention takes the measures as described in the claims above, and its effects are as follows.

[Effect]

Incoming circularly polarized radio waves are introduced into the waveguide from the open end. The introduced circularly polarized radio waves pass through the probe position and are reflected at the end of the probe.

In this case, the circularly polarized radio waves are converted into linearly polarized radio waves at the position of the probe by a reflector attached to the closed end. The linearly polarized radio wave excites the probe and induces an electrical signal in the probe.

〔Example〕

The drawings showing the embodiments of the present application will be described below.

In the primary radiator 1 shown in FIGS. 1 and 2, 2
A waveguide having a circular cross section is used, and one end 3 is open, while the other end 4 is provided with a reflecting wall 5 and is closed. Reference numeral 5a indicates a reflecting surface of the reflecting wall 5. The waveguide 2 is formed by cutting a metal rod, die-casting aluminum, or drawing or pressing a metal plate. Reference numeral 6 denotes a conical horn connected to the open end 3, and is provided to provide directivity that matches the aperture angle of the antenna. Note that this conical horn 6 may not be used. A probe 7 is provided inside the waveguide 1/4 at a position close to the open end 3, is formed of a metal rod, and is fixed to the waveguide 2 via an insulator 8. The distance from the open end 3 to the probe 7 is set to, for example, approximately A of the wavelength λg of the introduced radio wave within the waveguide 2 so that circularly polarized radio waves can stably exist in the space between the two. Further, the dimension L2 of the portion of the probe 7 existing inside the waveguide 2 is set to about 1/3 of the inner diameter of 1/4 of the waveguide. The base of the probe 7 extends outside by penetrating the wall of 1/4 of the waveguide, and is used to transmit the signal obtained by the probe 7 to the input end of the next stage, such as a converter or preamplifier. This is the output terminal 7a. The probe 7 may be formed of a narrow metal plate or a microstrip line on a dielectric substrate. Reference numeral 9 denotes a reflecting plate attached to the reflecting wall 5, which is in contact with the reflecting surface 5a and has an inclination angle θ with respect to the probe 7.
It is fixed to the waveguide 2 in an inclined state. The reflective plate 9
is formed of a metal plate or a dielectric plate whose surface is provided with a conductive layer formed by painting with conductive paint or plating. The axial dimension L1 of 1/4 of the waveguide in the reflecting plate 9 is approximately A of the wavelength λg,
The thickness is set to 1/32 of 1 g or less.

In principle, the tilt angle θ is set to 45°, but when the circularly polarized wave has an elliptical component, the angle is set to around 45°.

The waveguide 2 is fixed to the waveguide 2 by using an adhesive or by being press-fitted into the pipe. The distance L3 between the probe 7 and the front end of the reflecting plate 9, that is, the end 9a on the probe 7 side is 1/8 of the wavelength λg.
be reduced to a certain degree. In the figure, the reflector 9 is arranged at an inclination as shown by an imaginary line of 9° for left-handed circularly polarized waves, and for right-handed circularly polarized waves.

Next, reception of circularly polarized radio waves by the primary radiator will be explained. When left-handed circularly polarized radio waves arrive from a microwave transmission point such as a broadcasting satellite directly or after being reflected by a parabolic reflector toward the conical horn 6, the radio waves pass through the horn 6 and enter the waveguide 2. is introduced from its open end 3. The introduced circularly polarized radio wave passes through the position of the probe 7 and reaches the reflector 9. The reflector 9 has a front end 9a of the circularly polarized radio wave whose component is parallel to the surface direction of the reflector 9. The vertical component is allowed to proceed toward the reflective surface 5a.The vertical component that is allowed to proceed is reflected by the reflective surface 5a. As a result of these actions, at the position of the probe 7,
The circularly polarized radio waves introduced above are in the direction of the probe 7 (the longitudinal direction of the probe 7, the vertical direction in Figure 1.2).
It becomes a linearly polarized radio wave that vibrates in a direction parallel to the This linearly polarized radio wave excites the probe 7, and an electrical signal is generated in the probe 7. The signal thus obtained by the probe 7 is sent to the next stage from its output terminal 7a.

Next, with the structure shown in Figure 1.2, and 11.7 to 12.2 GH
When we measured the axial ratio and VSWR of a primary radiator designed and manufactured for receiving z circularly polarized radio waves, we obtained the results shown in Figures 3 and 4, respectively. The axial ratio fully satisfies the standard value of 1.0 dB or less, which is 1, and the VSWR satisfies the standard value of 1.5 or less.

〔Effect of the invention〕

As described above, in the present invention, when a circularly polarized radio wave arrives, the circularly polarized radio wave introduced into the waveguide 2 is changed to a linearly polarized radio wave, and the linearly polarized radio wave is The probe 7 has an open end 3 through which circularly polarized radio waves are guided.
Since the reflector 9 behind the probe 7 generates a linearly polarized radio wave at the position of the probe 7, in front of the probe 7 there is no large phase difference as in the prior art. There is no need for any space for placing the plate, and the thickness of the wave tube can be made shorter, which has the effect of making it possible to reduce the bulk of the primary radiator.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a longitudinal cross-sectional view;
FIG. 2 is a front view, FIG. 3 is a graph showing the measurement results of the axial ratio, and FIG. 4 is a graph showing the measurement results of VSWR. 2... Waveguide, 7... Probe, 9... Reflection plate. Figure 1 Figure 3 Figure 3

Claims (2)

[Claims] 1. It has a waveguide that is open at one end to introduce circularly polarized radio waves and closed at the other end to reflect the introduced radio waves. A probe is provided at a position close to the open end through which the radio waves are guided, and the probe is arranged so that an electrical signal is excited by the linearly polarized radio waves. A primary radiator for circularly polarized waves equipped with a reflector to convert radio waves into linearly polarized radio waves at the position of the probe. 2. It has a waveguide that is open at one end to introduce circularly polarized radio waves and closed at the other end to reflect the introduced radio waves. A probe is provided in the waveguide at a location 1/4 of the wavelength of the radio waves from the open end through which the radio waves are guided, and a probe is provided in which an electric signal is excited by the linearly polarized radio waves, and The other end of the waveguide is configured to convert the introduced circularly polarized radio wave into a linearly polarized radio wave at the position of the probe.
A primary radiator for circularly polarized waves equipped with a reflector with a length of /4.