JPH0454703A - Feeder - Google Patents

Abstract

PURPOSE:To use a radial line slot antenna for various types of polarized waves in common and to improve the antenna aperture efficiency by providing a matching post stood upright onto a center matching plate and a point loading to a tip of the matching point. CONSTITUTION:A center matching plate 22 is provided to a guide axis of a circular waveguide 20, the diameter and thickness of the matching plate 22 are selected so that a wave due to reaction from a middle plate 7 and a reflected amount from the matching plate 22 have equal magnitude but opposite phase thereby canceling the reaction from the middle plate 7 opposite to a conical horn 21. On the other hand, the transmission wave propagated from the center of a lower radial waveguide 5 to its circumferential part radially is reflected in a double corner 10, a slot plate 8 and an absorption body 11 or the like and the reflected waves are matched at the matching post 23 over a broad band. Thus, the antenna is used for various types of polarized waves in common and the antenna aperture efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a power feeding device suitable for use in a radial line slot antenna that receives sub-millimeter wave bands for satellite broadcasting, satellite communications, etc., for example.

"Prior Art" In recent years, various planar antennas have been developed with the practical use of satellite broadcasting, and among these is a radial line slot antenna that uses a radial waveguide. The structure of this radial line slot antenna is shown in FIG.

In this figure, 1 is a rectangular waveguide section, 2 is a probe inserted in the electric field direction of the transmitted wave to pick up the TE, 11 waves, and is formed in common with the center conductor of the coaxial line 3. The axially symmetrical TEM wave of the coaxial line 3 is transmitted through the matching element 4
The light is supplied radially from the center of the lower radial waveguide 5 to the periphery via the lower radial waveguide 5.

The rectangular waveguide section 1, the probe 2, the coaxial line 3, and the matching element 4 constitute a power feeding device.

Next, the lower radial waveguide 5 is attached to a metal disc frame 6.
and a middle plate 7, and a highly foamed dielectric (having a dielectric constant approximately equal to that of air) filled between these.

On the other hand, an upper radial waveguide 9 is composed of the intermediate plate 7, the slot plate 8, and a low-foaming dielectric material filled between them. Here, the permittivity of this low foam dielectric is ε
Then, the internal wavelength of the transmitted wave in the upper radial waveguide 9 is shortened by l/rε, so the upper radial waveguide 9 is called a slow wave circuit.

The slot plate 8 has a slot array formed on a metal disk by etching or the like. IO is a double corner for bending the transmission wave emitted in the radial direction from the lower radial waveguide 5 and introducing it into the upper radial waveguide 9. This double corner 10 is formed by bending the peripheral edge of the frame 6. 11 is an absorber lined with a cylindrical conductor 12. This absorber l
l absorbs and attenuates the magnetic field generated by the current flowing on the surface of the cylindrical conductor 12. A radome 13 covers the front surface of the antenna and, together with the frame 6, makes the antenna a sealed structure. An upper spacer 14 made of a highly foamed dielectric is filled between the radome 13 and the slot plate 8, which allows the middle plate 7 and the slot plate 8 to adhere to each dielectric, thereby improving their electrical performance. is stabilized. 15 is a rubber ring for peripheral protection.

According to the above structure, the TE10 wave of the transmission wave inputted into the rectangular waveguide section 1 is guided to the coaxial line 3 by the probe 2 and converted into a TEM wave having an axisymmetric waveform. The transmission wave that has proceeded to the coaxial line 3 then smoothly proceeds to the lower radial waveguide 5 via the matching element 4, and is transmitted radially from the center to the periphery.

Next, the transmitted wave in the lower radial waveguide 5 is bent at the double corner 10 on the periphery and proceeds to the upper radial waveguide 9. Most of the transmitted waves bent at this double corner IO are radiated into space through the slot array disposed on the slot plate 8, and the rest travels toward the center of the upper radial waveguide 9 and is absorbed into the absorber. It is absorbed and attenuated by 11.

In such a radial line slot antenna, polarization is determined according to the shape and arrangement of each slot array arranged on the slot plate 8. For example, if the slot plate 8 is sequentially arranged with a pair of square-shaped slots on a predetermined spiral line so that their phases differ by 90 degrees from each other, It becomes an antenna.

"Problem to be Solved by the Invention" Incidentally, in satellite communications, a polarization sharing system is adopted in which vertically polarized waves and horizontally polarized waves are used simultaneously, and it is difficult to apply the above-mentioned radial line slot antenna to these systems. This antenna needs to be polarized.

However, in the conventional power feeding device described above, even if a vertically or horizontally polarized transmission wave is fed, it is converted into an axially symmetrical TEM wave through the coaxial line 3. As a result, only a single polarized wave, ie, only a polarized wave plane depending on the slot shape of the slot plate 8, is radiated, so there is a problem that polarization cannot be shared. In addition, when polarization is shared, it is necessary to prevent the aperture efficiency of the antenna from decreasing.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a power feeding device that uses a radial line slot antenna for dual polarization and improves the aperture efficiency of the antenna.

"Means for Solving the Problem" According to the invention described in claim 1, there is provided a circular waveguide that transmits horizontally and vertically polarized waves simultaneously and independently, and TE, which is the basic form of this circular waveguide. a conical horn having a first aperture surface for diffusing the 11 waves, and a conductor disk provided at a position facing the first aperture surface,
a center alignment plate disposed on the plate surface of the circular conductor plate with the tube axis of the circular waveguide as the center; and a conductor cylinder of a predetermined length centered on the tube axis, the center alignment plate being arranged on the center alignment plate. A matching post erected on the
It is characterized by having a tip loading formed of a small conductor disk.

Further, according to the invention as claimed in claim 2, there is provided a rectangular waveguide that transmits horizontally and vertically polarized waves independently and simultaneously, and an aperture surface for diffusing the TE10 wave, which is the basic form of this rectangular waveguide. a conductor disk provided at a position opposite to the opening surface, the center alignment plate being arranged on the plate surface of the circular conductor plate with the tube axis of the rectangular waveguide as the center. a conductor cylinder of a predetermined length centered on the tube axis, an alignment post erected on the center alignment plate, and a tip loading provided at the tip of the alignment post formed of a small conductor cylinder. It is characterized by having the following.

Further, the invention as set forth in claim 3 is characterized in that a coaxial horn is formed by providing a choke around the periphery of the first opening surface of the conical horn and using this choke as the second opening surface.

"Operation" According to the invention described in claim 1, the TE, 11 waves supplied through the circular waveguide are diffused by the conical horn and proceed to the radial waveguide. At this time, the center matching plate cancels the reaxilon from the circular conductor plate directly facing the first aperture of the conical horn, and the matching post and tip loading cancel the reflected waves from other parts of the antenna, and the tip of the matching post Further broadband matching is achieved by loading.

According to the second aspect of the invention, the TE10 wave supplied through the rectangular waveguide is diffused by the pyramidal horn and travels to the radial waveguide. At this time, the center matching plate cancels the reaxilon from the circular conductor plate directly facing the aperture of the pyramidal horn, and the matching post and tip loading cancel the reflected waves from other parts of the antenna, and the tip of the matching post is loaded. This further provides broadband matching.

Further, according to the invention as claimed in claim 3, the radiation wave of the conical horn has a directivity in which the electric surface is sharp and the magnetic surface is broad, that is, the projection onto the plane perpendicular to the radiation axis is elliptical. , does not improve the aperture efficiency as an excitation wave for an antenna with a circular aperture surface.

This is shaped into an axially symmetrical beam of equal beam width using a coaxial horn. As a result, the beam pattern in a plane perpendicular to the radiation axis becomes circular, and if an antenna with a circular aperture is excited, the aperture efficiency will be significantly improved.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment] FIG. 1 is a perspective sectional view showing the structure of a radial line slot antenna to which a polarized wave supply power supply device according to the present invention is applied. In this figure, parts corresponding to those in FIG. 7 are given the same numbers, and their explanations will be omitted. The difference between this figure and the one shown in FIG. 7 is that the power supply device is composed of a circular waveguide 20-, a conical horn 21, and a matching member to be described later.

First, in FIG. 1, a circular waveguide 20 is capable of transmitting both vertically and horizontally polarized waves independently and simultaneously. TE, which is the appearance.

It is designed to spread the waves. The aperture of this conical horn is generally a small horn with a diameter of about 1.2λ, where λ is the wavelength of the frequency used.

Next, FIG. 2 is a sectional view showing the structure of this power supply device. In the figure, 22 is a center alignment plate, which is a conductor disk provided on the plate surface of the intermediate plate 7 so as to be centered on the tube axis of the circular waveguide 20. A conductor cylindrical alignment post 23 having the same axis as the center axis of the center alignment plate 22 is provided on the center alignment plate 22 . Furthermore, a tip loading 24 formed of a small conductive cylinder is provided at the tip of the alignment post 23.

According to the above structure, the transmitted wave within the circular waveguide 20 is TE1
One wave is diffused by the conical horn 21 and travels to the lower radial waveguide 5. However, there is a reactor from the middle plate 7 directly facing the opening of the conical horn 21, and when this returns to the circular waveguide 20, it degrades the input return loss of the antenna. Therefore, the center alignment plate 22 described above is provided in order to cancel out this rear axis and the reflected wave on the surface of the center alignment plate 22.

That is, the center matching plate is arranged so that the amount of reflection from the middle plate 7 within the angle range that the conical horn 21 sees is equal to the amount of reflection from the center matching plate 22, and the phases of the reflected waves are opposite to each other. By setting the size and thickness of the conical horn 22, the rear axis from the middle plate 7 directly facing the conical horn 21 can be canceled out.

On the other hand, the transmission waves propagating radially from the center of the lower radial waveguide 5 to the periphery are transmitted through the double corner 10 and the slot plate 8.
The reflected waves are also reflected by the absorber 11 and the like, but these reflected waves are matched by the matching post 23. In this case, the reflected waves are canceled according to the height of the matching post 23, and furthermore, in this matching, by appropriately sizing the diameter and height of the tip loading 24, broadband matching is made possible. There is.

Next, in the slot plate 8, in order to radiate the horizontally polarized wave and the vertically polarized wave introduced into the upper radial waveguide 9 through the above-mentioned power supply device in equal amounts and separately, the slot plate 8 A plurality of cross-shaped slots are arranged on a plurality of concentric circles with a predetermined radius from the center. As a result, horizontally or vertically polarized waves are emitted from these slot arrays,
It becomes polarized.

By connecting a circularly polarized wave generator to the input/output end of the power supply device according to the above embodiment and using a slot plate 8 consisting of a slot array in which X-shaped slots are arranged on concentric circles at predetermined intervals, circularly polarized waves can be generated. It becomes a polarized antenna. Broadcasting satellites in Europe and Africa, where neighboring countries are assigned different polarizations, allow people living in neighboring countries to simultaneously watch their own satellite broadcasts.

[Second Embodiment] The power supply device according to the present invention has a TE II polarization plane as described above.
T, which is an excitation wave with a plane of polarization perpendicular to the wave,
This is a power supply device that operates and acts in exactly the same way for E Io waves. Therefore, there is a rectangular waveguide as another waveguide that can transmit vertically and horizontally polarized waves independently and simultaneously, and a second embodiment using this will be described.

FIG. 3 is a perspective sectional view showing the structure of a radial line slot antenna to which the second embodiment is applied. As shown in this figure, when the square waveguide 30 is applied to the above-described power supply device, if a pyramidal horn 31 is used instead of the conical horn 21, the above-mentioned TE11 wave is
The wave becomes 0, and the operation and effect are exactly the same as those described above.

[Third Example] By the way, in the basic configuration of the circular waveguide 20 described above, Z'
The energy distribution of the I'B and 11 waves is a uniform distribution within the electric surface and a cosine distribution within the magnetic surface.

Therefore, the main beam directivity in the power supply device is
As shown in the figure, the electric surface is sharp as shown by the solid line 40 and has a high sidelobe level, while the magnetic surface is broad and has a low sidelobe level as shown by the dotted line 41. Show characteristics. When we project this directivity onto a plane perpendicular to the radiation axis, we get
This results in an oval beam pattern. Therefore, when an antenna with a circular aperture is excited with such a beam pattern, the aperture efficiency of this antenna is low.

Therefore, in the third embodiment, while polarization is shared,
A power supply device with improved aperture efficiency will be described. Fifth
The figure and FIG. 6 are a perspective sectional view and a sectional view showing the structure of the third embodiment. In this figure, parts corresponding to those in FIGS. 1 and 2 are given the same numbers, and their explanations will be omitted. These figures differ from the power supply device shown in FIGS. 1 and 2 in that a choke 25 is provided around the opening of the conical horn 21 to form a coaxial horn 50. That is, the choke 25 has an annular cavity provided along the periphery of the opening of the conical horn 21, and this is the conical horn 2! It is integrally formed with. This coaxial horn 50 is 2J, (x
)/x (where J + (x) is a Bessel function of order -) Based on well-known design standards, the conical horn 2
A first aperture diameter of the choke 25 and a second aperture diameter including the choke 25 are defined. Here, the depth of the choke 25 is approximately λ/4.

The coaxial horn 50 having such a structure can beam-form the radiation waves from the circular waveguide 20 into an axially symmetric beam with equal beam width. That is, TM11 is added to the TE II wave.
As the waves are superimposed, the shape projected onto a plane perpendicular to the radiation axis of the beam pattern of the horn 50 becomes circular. Therefore, excitation waves with the same phase and equal amplitude, that is, an axially symmetric beam with an equal beam width, are generated. The excitation wave is supplied to the circular aperture surface, and the aperture efficiency is significantly improved. Moreover, by doing so, the shape is compact and suitable as a power feeding device for a flat antenna.

Furthermore, in the case of a combination of the square waveguide 30 and the pyramidal horn 31 shown in FIG.
The zero-wave electric field is used in a direction perpendicular to the wall, but
This is rotated 45 degrees around the horn axis to make the electric field direction diagonal. That is, by using the pyramidal horn 31 as a diagonal horn, the transmitted wave to the radial waveguide becomes an axially symmetric beam with equal beam width, and the aperture efficiency can be significantly improved.

In addition, when beam shaping is performed to have an axially symmetrical uniform beam width without using the coaxial horn 50 described above, for example, a double flare horn in which the diameter of the conical horn 21 in the axial direction is abruptly changed to create a step, or a conical horn 21 is used. There are dielectric loaded horns in which a dielectric ring is inserted into the horn. These horns have large first aperture diameters and large axial lengths, and are not suitable for excitation of planar antennas. Further, corrugated horn is not suitable for mass production and is not economical.

The above-described embodiments have been described as a transmitting system, but it goes without saying that this is a "reversible principle" and the same thing holds true for a receiving system. For example, if you want to separate and receive each polarized wave from a transmission wave containing a mixture of horizontal and vertical polarized waves, the above-mentioned circular waveguide 20 is equipped with a branching device for orthogonal polarization separation (
An LNB (low noise block converter) is connected to each polarized wave output terminal of this OMT. In this way, each polarized wave can be received by selecting a vertically or horizontally polarized signal converted into an intermediate frequency by the LNB using a changeover switch at the input end of the receiver.

"Effects of the Invention" As explained above, according to the present invention, the circular waveguide (
A TE11 wave (or TB10 wave) supplied through a conical horn (or a rectangular waveguide) is diffused by a conical horn (or a pyramidal horn) and travels to a radial waveguide. At this time, the center matching plate cancels the accresine from the circular conductor plate directly facing the opening of the conical horn (or pyramidal horn), and the matching post and tip loading cancel the reflected waves from other parts of the antenna.
Since broadband matching is performed, the radial line slot antenna can be used for polarization.

In addition, since the TE, 11 waves supplied through the circular waveguide are shaped into an axisymmetric beam by the coaxial horn,
The beam pattern in the plane perpendicular to the radiation axis becomes circular. Thereby, the aperture efficiency of the antenna having a circular aperture surface can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a perspective sectional view showing the structure of a radial line slot antenna to which the first embodiment is applied, FIG. 2 is a sectional view showing the structure of the first embodiment, and FIG. FIG. 4 is a diagram showing the directivity of the horn antenna 21, and FIG. 5 is a perspective cross-sectional view showing the structure of the radial line slot antenna to which the third embodiment is applied. 6 are cross-sectional views showing the structure of the third embodiment, and FIG. 7 is a view for explaining the conventional example. 2... Center alignment plate, 23... Alignment post, 4... Tip loading, 0... Square waveguide, l... Pyramidal horn, 5...Choke, 50...Coaxial horn.

Claims (3)

[Claims] (1) In a power supply device for a planar antenna that includes a radial waveguide formed by a slot plate with a plurality of slots and a circular conductor plate facing the slot plate, horizontal and vertical polarization is possible. a circular waveguide that transmits the TE_1_1 waves independently and simultaneously; a conical horn having a first aperture surface for diffusing the TE_1_1 wave, which is the basic configuration of the circular waveguide; and a conical horn facing the first aperture surface. a center alignment plate disposed on the plate surface of the circular conductor plate with the tube axis of the circular waveguide as the center; and a center alignment plate provided at a position centered on the tube ring; What is claimed is: 1. A power supply device comprising: a conductor cylinder, comprising: an alignment post erected on the center alignment plate; and a tip loading provided at the tip of the alignment post and formed of a small conductor cylinder. (2) In a power feeding device for a planar antenna comprising a radial waveguide formed by a slot plate with a plurality of slots and a circular conductor plate facing the slot plate, horizontal and vertical polarization is possible. A rectangular waveguide that transmits the TE_1_0 waves independently and simultaneously, a pyramidal horn having an aperture for diffusing the TE_1_0 wave, which is the basic configuration of this rectangular waveguide, and a conductor provided at a position facing the aperture. A center alignment plate that is a circular plate and is arranged on the plate surface of the circular conductor plate with the tube axis of the rectangular waveguide as the center, and a conductor cylinder of a predetermined length that is centered on the tube axis. . A power feeding device comprising: an alignment post erected on the center alignment plate; and a tip loading provided at the tip of the alignment post and formed of a small conductive cylinder. (3) The power feeding device according to claim 1, wherein a choke is provided at the periphery of the first opening surface of the conical horn, forming a coaxial horn with this choke as the second opening surface.