JPS59131203A - Microwave antenna - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a microwave antenna, and more particularly to a dual-reflector microwave antenna.

Purpose The purpose of the present invention is to provide a radio-frequency device which can be manufactured efficiently and economically at relatively low cost and which is commonly used in conjunction with this Yuzu antenna.
An object of the present invention is to provide a microwave antenna in which most of the equipment is located where the reflector resides. A related objective is the antenna aperture (ap
The non-working part (blockage) of
) @ Minimize, facilitate antenna matching, and operate exposed to signals (exposing 5er
vice) and the various hazards posed by direct exposure to the electromagnetic energy of the signals transmitted and/or received by the antenna.
maintenance personnel (maintena) facing
An object of the present invention is to provide a complete microwave antenna that substantially eliminates the need for a microwave antenna.

A further object of the invention is to provide a microwave antenna which can be used for all feedhorns with small smooth walls. In each frequency band, orthogonally polarized signals (orthogonally
The object of the present invention is to provide a complete set of microwave signals that can be used for transmitting and/or receiving microwave signals with or without polarized signals.

A further auxiliary object of the present invention is to create various desired combinations of VSWR (voltage standing wave ratio), directional gain and RPE (radiation pattern envelope) (t4i1or).
A good function that can be used (ρcr-formanc
c) To provide a microwave antenna that provides all the characteristics. A related object is to provide an overall microwave antenna with relatively high effectiveness.

Yet another subsidiary object of the present invention is the United States Federal Communications Commission (U.S.C.) for ground station antennas.

S,Federtrl Communication
Recent RP submitted by Com1-session)
The purpose of the present invention is to provide a microwave antenna that satisfies the requirements of E-specification.

Structure of the present invention C. In a microwave antenna consisting of a combination of Halabola type reflectors, the entire reflecting surface is located between the reflector and the focal point of the reflector and has a symmetrical shape with respect to its own center. The auxiliary reflector and the central portion of the reflecting surface are inclined along the axis in a direction facing forward from the reflector, and the degree of the inclination decreases as the radius of the auxiliary reflector increases. , the radially outer part of the auxiliary reflector is inclined toward the reflector side along the axis, and the degree of inclination increases as the radius of the auxiliary reflector increases; A feed horn for receiving all of the microwave signals and transmitting the microwave signals to the auxiliary reflector, and a reflecting surface of the auxiliary reflector to receive almost all of the energy sent through the feed horn or reflected by the reflector. It is given a position and size that cuts all +S.

Embodiment The following is a first embodiment of an antenna embodying the present invention.
- Detailed explanation according to Figure 3.

The double reflector antenna shown in FIG. 1 includes a reflector 10 and a feed horn (( 'eed horn)l 1° and an auxiliary reflection 1fL13.

In the transmission mode, the feed horn 11 receives a microwave signal through the entire waveguide 12, and sends it to the microwave signal reflecting plate 13. The auxiliary reflecting plate 13 reflects the microwave signal to the reflection &10, and the reflecting plate 10 reflects the microwave signal -Qf in a substantially plane wave state due to its parabolic surface.

In the receiving mode, the paraholographic reflector 10 is illuminated by a plane wave, and the reflector 10 reflects this energy and sends it to the auxiliary reflector 13 as a spherical wave. and,? The first support plate 13 reflects the incoming energy onto the horn 11 and sends it through the entire cylindrical waveguide 12 to the receiver.

Similar to the conventional double reflector antenna, the auxiliary reflector 13 is located between the reflector 10 and the focal point F of the paraboloid of the reflector 10. In order to support the auxiliary reflector 13 at a desired position, the auxiliary reflector 13 is attached to the large diameter end of an insulating conical member 140 made of glass fiber, for example.

The conical member 14 has a small diameter side end that is connected to the reflecting plate 1.
It is fixed to the l\b 15 installed in the idiomatic link 16 of 0. The conical member 14 is formed relatively thin, and the VSWR
In order to avoid deteriorating the pattern, only negligible changes are made to the antenna device. On the other hand, the auxiliary reflector 13 has three or four grooves (pod S) extending from the end of the reflector 10 to the rear of the auxiliary reflector 13.
) is supported by Even when the non-operating portion of the aperture of the reflector 10 is minimized, the auxiliary reflector 13 intercepts almost all the energy sent through the entire feed horn 11 in the transmitting state, and also in the receiving state. The position and size are determined so as to block almost all the energy reflected by the reflection plate 10. In this embodiment, the ratio of the diameter of the auxiliary reflector 13 to the diameter of the reflector 10 is approximately 0.05. As with most dual reflector antennas, the auxiliary reflector 13 in the present invention preferably blocks at least 98% of the energy transmitted from the feedhorn 11. In order to obtain this result, the diameter of the auxiliary reflector 13 is set at the mid-band frequency (mi
-1) and frequency), and is located very close to the feed horn 11 at that position.

Feed horn 11 preferably has smooth walls;
and a medium band signal (mi
It is preferable to use a cylindrical waveguide having an inner diameter approximately equal to one wavelength of the dband signals. Such a feed horn 11 emits all signals having almost the same E-plane and H-plane patterns to the auxiliary reflector 13, and its manufacturing cost is extremely low. The length of the feed horn 11 in the narrow direction is simply an extension of the waveguide 12, so there is no need to consider it strictly.

The feed horn 11 and the waveguide 12 have the same inner diameter and are connected by connecting flanges 17 and 18 which are fixed to each other by a number of screws 19.

In order to prevent radiation from the outer surface of the feed horn 11 toward the reflector 10, the opening or free end of the feed horn 11 is connected to a short conductive cylinder 21 provided concentrically with the feed horn 11 and a short circuit. (shorting
) A quarter-wave choke consisting of a ring 22 (c
hoicc) 20. Cylindrical body 21
The inner peripheral surface of the feed horn 11 is spaced apart from the outer peripheral surface of the feed horn 11, and extends in the length direction of the feed horn 11 from one end of the feed horn 11 to a position approximately equal to a quarter wavelength.

The cylindrical body 21 is short-circuited to the feed horn 11 by a link 22, forming a coaxial choke 20 of a quarter wavelength for preventing current from flowing to the outer peripheral surface of the feed horn 11.

If desired, a funnel-shaped feed horn 11 may be used in place of the straight feed horn 11 of the above embodiment, or a tapered waveguide may have a different diameter from the completely straight feed horn 11. It is also possible to use it between a straight supporting waveguide 12.

According to an important aspect of the present study, a reflective surface is formed on the auxiliary reflective plate 13, and the reflective surface is symmetrical with respect to its entire center. And auxiliary reflex′! The center portion of l5L13 is inclined along the axis in the direction lfmfllj from the reflecting plate 10, and the degree of inclination decreases as the radius of the auxiliary reflecting plate 13 increases. Furthermore, the radially outward portion of the auxiliary reflector 130 is inclined toward the reflector 10 along the axis, and the degree of inclination increases as the radius of the auxiliary reflector 130 increases. Therefore, in this embodiment, the reflective surface of the auxiliary reflector 13 is inclined in a direction away from the reflector 10 between the center of the auxiliary reflector 13 and the radius r1, and is further inclined in the direction of the outer circumference of the auxiliary reflector 13 from the radius rl. It extends and slopes again toward the reflector 10 direction. J. In detail, the reflective surface of the auxiliary reflector 13 extends outward from the center of the auxiliary reflector 13 at a radius rl, is tilted away from the reflector 10, and the degree of inclination increases as the radius increases. On the contrary, it is decreasing.

When the reflecting surface extends from the radius r1 to the outer periphery of the auxiliary reflecting plate 13, it is inclined toward the reflecting plate 10, and conversely decreases as the radius increases to the degree of inclination. As a final result, the auxiliary reflector 13 has a concave cross-section.As is clear from FIG. It is provided at a position closer to a. That is, there is a shift in the axial direction between the center and the outer circumference of the auxiliary reflecting plate 13.

The combination of the misalignment in the axial direction and the concave cross-sectional shape of the auxiliary reflector 13 results in approximately equal radio waves being transmitted between the feed horn 11 and the reflector 100 via the auxiliary reflector 13 over the entire operating area of the opening of the reflector 10. A passage is created to minimize the loss of efficiency in the non-active parts of the apertures of the reflector 10 and the auxiliary reflector 13. In more detail,
The auxiliary reflector 13 is sent from the feedbone 11 with a spherical wavefront shape within the annular sector 8 of ffi between the small non-operating part at the center of the feed horn 11 (or the auxiliary reflector 13) and the outer periphery of the reflector 10. Reflects most of the energy. Similarly, reflection &10 is the shape of the outer edge of the auxiliary reflector 13 and the darkness of the reflector 10, that is, the outer shape of the non-operating part of the auxiliary reflector 13, and most of the energy from the auxiliary reflector 13? It's reflecting. Therefore, the non-operating part created by the feed horn 11 and the auxiliary reflector &13 is small from the beginning (a typical example is 12-140k).
Reflector plate 1017) at the frequency of ly, 5 of the entire aperture
%), then the shape of the auxiliary reflector 13 also reduces the negative effects of these non-active parts. Furthermore, this result is obtained by providing a relatively uniform distribution of the electromagnetic field (both in amplitude and phase) throughout the active portion of the aperture.

The antenna of the present invention not only has a simple structure and low manufacturing cost, but also has excellent functional characteristics. This antenna is fully configurable with different RPE, gain, and VSWR values for different uses. Any one of these characteristic values can be made optimal only if all the other characteristic values are reduced relatively slightly. In general, average performance depends on gain and VSWR.
It is obtained by balancing PE23.

5-8 show the antennas shown in FIGS. 1-4 in 7.
This figure shows the magnetic field when a waveguide section with a tapered surface of 62n (3 inches) is attached.

7. The waveguide section with a tapered surface of 62/7++ (3 inches) is a 7620 waveguide made of WC940 waveguide.
(3 inch) feed horn and a feed horn constructed from a wc6BOO waveguide. The mouth of the feed horn is located 254 rM (1 inch) away from the center of the auxiliary reflector 13, and the center of the front surface of the auxiliary reflector 13 is 2.01 m (0.0 m) away from the focal point of the reflector.
, 79' inches] in the forward position. This antenna is
It has a reflector 10 with a diameter of 450α (15 feet) and an auxiliary reflector 13 with a diameter of 225CM (8,86 inches), both 10.13 being supported by a column instead of the insulating cone member 14. .Figures 5 and 6 are 12.250)lz
Figure 7.8 shows the pattern of the 8-plane and the H-plane at 14.5 GHz. In FIGS. 5 to 8, an enlarged size note is used to indicate an enlarged pattern, and a reduced size note is used to indicate a reduced pattern. The curves indicated by chain lines in Figs. 5 to 8 are the maximum side lobe values from f to T? To indicate the specific value established by the Federal Communications Commission of the United States of America, namely dBi(0) = 32 2
5]0g10θ. Note that even if all 7 degrees are exceeded, only less than 10% of the side lobes exceed a specific value. This antenna has passed tests under standards of Fl 12.25 GH7 and 145 QHz, and trial runs are being conducted using an even narrower main beam (f). The plurality of first sidelobes are formed relatively high, which has the characteristics of many double reflector antennas. If you want to reduce the number of first side lobes, you can use an auxiliary reflector with a slightly different shape, but this will inevitably reduce the gain of the antenna. The resulting antenna directional gain is shown below. Note that the directivity loss t+<i also includes the reduction in the characteristics of the approximately M8 surface of reflection &10 and auxiliary reflection 8!13.

12.250ELz 53.69dB 53.64
dB *53.67dB [67, last efficiency (ell'1cency)) 14.50 GH7,54,95dB 54.74
dB *54.85 dB [63, chick efficiency] The value of return loss is when the antenna is 1 in the image frequency band.
．． All are shown having a V S WR in the range of 25 to 1.30.

In a separate aspect of the invention, the antenna is similar to the antenna described above, but with the focal point F7 of the reflector 10. I.et al.678rIR
(2,6 finches) installed in front of i76.2z (30
It has an auxiliary reflector 13 of 4.45 z
It has a funnel-shaped feed horn with (1,75 in-f-) holes. This antenna is 8°7GHz~4
．． Tested at various frequencies within the 4 GHz range, the results are shown in the table on the next page.

The auxiliary reflector 13 is the same as described above, but is provided on the glass fiber instead of the pillar. This auxiliary reflection @Z13i was tested in the 3.95 GHz frequency band and produced the amplitude and phase pattern shown in Figure 9.10. What is shown in Figures 9 and 10 is the E-side pattern, and although the ■-side pattern is not shown, it is especially
, appears to be similar to the E-plane pattern in the test results at 95 GHz. As is clear from FIGS. 9 and 10, the non-operating portion of the auxiliary reflector 13 extends to a position 16° from the center of the pattern, and the edge of the reflector 10 is located at a position of about 74°. Both the amplitude pattern and the phase pattern were measured on a constant radius line with respect to the focus of the paraboloid of the reflector 10. As is clear from FIG. 9, the amplitude increases rapidly near the outer end of the non-active portion of the auxiliary reflector 13. The amplitude continues to increase slowly in the main part of the working part of the aperture, that is, between the end of the non-working part of the auxiliary reflector 13 and the outer periphery of the reflector 10. At the outer periphery of the reflector 10, the amplitude decreases rapidly. This fully guarantees that the microwaves are uniformly distributed over the entire area of the open aperture f' of the reflector plate 10.

The phase pattern remains relatively constant as it passes through the open portion of the aperture, as can be seen in FIG.

It is possible to completely vary the size of the antenna described above and use it in other frequency bands to derive frequency-dependent results. You can also cover this kind of antenna (ShrOudS)
The loss (spillover) f of the reflector 10 is
It is also possible to decrease and improve the PEy within this region.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view of the central part of a microwave antenna that embodies this research, Figure 2 is an enlarged cross-sectional view of the auxiliary reflector part of the antenna in Figure 1, and Figure 3 is the same antenna as in Figure 1. 4 is an enlarged cross-sectional view of the feed horn portion of the
A side view showing the entire auxiliary reflector of the antenna shown in Fig. 5,
Figure 6 is a diagram showing the E-plane and E-plane patterns at a frequency of 12.25 GHz, respectively, formed by the antenna equipped with the present invention, and Figures 7 and 8 are the same antenna that forms the entire pattern of Figures 5 and 6. Figures 9 and 10 show the patterns of the E-plane and E-plane at a frequency of 14.501 (y), respectively, formed by changing the size of the auxiliary reflector shown in Figure 1.2.4. It is a diagram showing the amplitude and phase pattern obtained at a frequency of 3.g5GI-1z.Reflector 10, feed horn 11, auxiliary reflector 13°. Engraving of drawings (no changes in content) FIG, 1 FIG, 4 FIG, 9 0G, t. 1. Case table 1 \ 1988 special h! 1 Application No. 1eE889 2 Name of the invention Microwave antenna amplifier 3, relationship with supplementary IF processor A'1 i, 11i+'f Applicant 11
Location: United States of America 607I62 A-Lan 1-Park, Illinois
~Lee-1~ 10b00 Name Andrico] - Poreshi 31 (Name
representation)
Box No. 7 United States of America 4, Agent

Claims (1)

[Claims] 1. In a microwave 7-antenna with a parabolic reflector (kW), the reflector (10) and the focal point (F) of the reflector (10)
) and forms a symmetrical reflecting surface with its center +L>' as the center, and an auxiliary reflecting plate (13) that is located between ), and the degree of inclination increases as the radius of the auxiliary reflective plate (13) increases, and the radius of the sleeve auxiliary and reflective plate (13). The outward part of the direction is inclined toward the reflecting plate (10) but 11 along the axis, and the degree of inclination increases as the radius of the auxiliary reflection 1jJsL (13) increases, and the auxiliary reflection &( 13) A feed horn (11) for receiving all the microwave signals from 7) and transmitting them to the full-length sub-reflector (13).
], and the reflective surface of the auxiliary reflector (13) is positioned and sized so as to completely block almost all of the energy transmitted through the horn (1i')k or reflected by the reflector (10). A microwave antenna having all the characteristics given above. 2. The feed horn (11) is the reflector (10).
On the axis of the reflector & (10) and the auxiliary reflector (13
) and has a V8WR2 of about 1.3 or less over the entire operating frequency band. 3. Said feed horn (11)+'j:, the signal is sent to the auxiliary reflector (13) in which the F-plane pattern and the 11-plane pattern are approximately equal. Microwave antenna described. 4. The microwave antenna according to claim 1, wherein the feed horn (11) is a waveguide with a smooth wall surface. 5. A hole in the feed horn (11). 6. The microwave antenna according to any one of claims 1, 3, and 4, characterized in that the antenna has a size substantially equal to one wavelength in a medium band frequency.6. (11) is a rigid (rigid) extending through the entire center of the reflector (10) along its axis.
) The microwave antenna according to claim 1, wherein the microwave antenna is supported by a waveguide. 7. The microwave antenna according to claim 1, wherein the auxiliary reflector (13) is supported by an insulating conical member (14) fixed to the reflector (10). 8 The auxiliary reflector (13) is connected to the feed horn (11).
2. The microwave antenna according to claim 1, wherein the microwave antenna is positioned and sized to block at least about 98% of the energy transmitted from the antenna. 9 The center of the auxiliary reflector (13) is located at the center of the auxiliary reflector (13).
The microwave antenna according to claim 1, wherein the microwave antenna is closer to the Sekiguchi plane of reflection & (10) than the outer peripheral part of (13). 10. The reflective surface of the auxiliary reflective plate (13) is characterized by forming a smoothly continuous concave curve between the center of the auxiliary reflective plate (13) and any one point on its outer periphery. A microwave antenna according to claim 1. ]1 In a microwave antenna having a scattering reflector, the reflector (10) and the focal point C of the reflector (10)
The auxiliary reflector (13) located between the auxiliary reflector (13) and the included auxiliary reflector (13) have a reflective surface that is closer to the aperture plane (a) of the reflector (10) than the outer periphery of the auxiliary reflector (13). The central part of the opposite reflecting surface is inclined along the axis in the direction away from the reflecting plate (10) (-1). Accordingly, the outer part of the auxiliary reflector (13) in the radial direction is inclined toward the reflector (10) along the axis, and the degree of inclination is equal to the radius of the auxiliary reflector (13). E A feed horn (11) for sending a signal to the auxiliary reflector (13) in which the plane/f-turn and the H-plane pattern are almost equal, and the auxiliary reflector (13).
3) The reflecting surface is positioned and sized so as to block almost all of the energy sent through the feed horn (11) or reflected by the reflector (10). microwave antenna.