JPH03219708A - Waveguide slot array antenna - Google Patents

Abstract

PURPOSE:To improve the antenna reception efficiency due to the reduction in power loss at a feeding part by arranging a window communicating rectangular waveguide of each set to part of a common wall of a rectangular waveguide set comprising two adjacent rectangular waveguides and feeding the window for the rectangular waveguide set. CONSTITUTION:A feeding probe 4 is connected respectively to a rear side 1B at a right angle and the feeding probe 4 is penetrated through a dielectric plate 6, a ground conductor 7 and the rear side 1B of a waveguide 1 and projected respectively to the middle part of the waveguides 1 being two guides one set at the part of the four link windows 8. When a prescribed high frequency power is applied from a feeding power supply 5A, the power reaches each feeding probe 4 with equi-power and equi-phase via branch parts 5C, 5D and finally eight radiation waveguides 1 are excited with equi-power and equi-phase and act like a prescribed transmission antenna. Thus, the feeding structure is simplified and the reception efficiency of the antenna is improved because of the power loss of the feeding part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a waveguide slot array antenna in which a plurality of waveguides each having a slot for radiation are arranged in parallel to form an array.

[Prior Art] An antenna in which a large number of radiation slots are formed in a rectangular waveguide and a plurality of such waveguides are arranged in parallel to form a planar array has been relatively well known. . Specifically, for example, W, J, GETSINGER.

“EllPtically Po1arized L
eaky-WaveArray IRE TRAN
SACTIONS ON ANTENNAS ANDP
ROPAGATION, pp165-172. Ma
There is one reported in R.C.R.H., 1962.

This antenna is made by forming a number of cross-shaped slots at predetermined intervals in the longitudinal direction at positions offset from the center of the wide surface (H-plane) of a single rectangular waveguide with a uniform cross section. This is a one-dimensional array antenna for solar polarization, in which high frequency waves are input from one end of the tube using a waveguide adapter, and the other end has a non-reflection termination structure.

This antenna is basically a beam tilt type, and
Although it is a series sequential feeding type, it has the characteristic that it can have a relatively wide bandwidth, and by arranging it in a planar shape, it can be used to create high-performance and highly functional antennas for receiving satellite broadcasting, for example. can be configured.

To construct such a planar array antenna,
In order to supply power in the same phase to each of the slot-formed radiation waveguides (hereinafter referred to simply as waveguides) and to prevent the generation of grating lobes, the waveguide It is necessary that the spacing between the lines be approximately 0.90 or less, where the spatial wavelength for the frequency used is 0.

As a structure that satisfies these conditions, the inventor has previously proposed a power feeding structure using a microstrip circuit (see Japanese Patent Application No. 1983-210973 entitled "Waveguide Slot Array Antenna").

FIGS. 8 and 9 show an example of a planar waveguide slot array antenna using such a microstrip circuit. In these figures, reference numeral 11 indicates the waveguides, and in this example, eight radiation waveguides 11 have radiation slots IIc provided on one wide surface of each of them facing in the same direction, and adjacent to each other. The narrow-width LIDs are arranged in parallel so that they are in contact with each other. Hereinafter, the wide surface provided with the radiation slots 11C in this parallel state will be referred to as the radiation surface 11A, and the opposite surface will be referred to as the back surface 11B. One end of these waveguides 11 is closed with a conductor short-circuit plate 12, and the other end can be short-circuited or open, or a radio wave absorber can be installed to create a non-reflection peripheral structure, as desired. . Further, each waveguide 11 is provided with a feeding probe insertion hole LIE as shown in FIG. 9, which will be described later.

In the waveguide slot array antenna of this example, a ground conductor 17, a dielectric plate 16, and a microstrip branch line 15 are sequentially arranged in layers in contact with the back surface 11B, but these three layers are made of so-called double-sided copper. It is constructed by a well-known method of manufacturing from a single plate called a stretched laminate using processes such as etching. Note that a circuit composed of these three layers is called a microstrip circuit.

Here, as shown in FIG. 8, the microstrip branch line 15 is connected from the power source 15A to the branch section 15C2150,
The structure is such that the branches are sequentially branched at 15E and finally reach eight branch ends 15B. In this example, the actual line lengths from the power source 15A to each of the eight branch ends 15B are made equal, and the electric power is also equally divided.

Note that although not strictly shown in the figure, there is a branch portion 15G.

Of course, it is assumed that impedance matching is achieved in 15D and 15E.

Further, a power supply probe 14 is connected to each branch end 15B at right angles to the back surface 11B, and the power supply probe 14 penetrates through the dielectric plate 16, the ground conductor 17, and the power supply probe insertion hole 11E, and connects each conductor. It is provided protrudingly within the wave tube ll.

Note that the ground conductor 17 is provided with a hole similar to the power supply probe insertion hole 11E, and these holes and the power supply probe 14
A dielectric sleeve 13 is inserted between the two and stably fixes the power supply probe 14.

The structure in which each feeding probe 14 is protruded into each waveguide 11 in this way is basically known as a so-called coaxial waveguide conversion structure, and the microstrip branch line 1
The thickness and length of the feeding probe 14 and its distance from the shorting plate 12, the narrow side 11 of the waveguide 11, etc.
By appropriately setting the distance from zero or the size of the feeding probe insertion hole 11E, it is possible to feed power with almost no reflection.

In such a structure, when a predetermined high frequency power is supplied from the power source 15A, this power is transmitted to each branch section 15G, 15.
Each feeding probe 14 with equal power and equal phase after 0.15E
Finally, the eight radiation waveguides 11 have equal power,
Excited with equal phase. In addition, in the case of such a power branch structure,
The spacing between the eight branch ends 15B can be set almost freely, and it is completely acceptable to set it to less than 0.9λ0 as described above (it satisfies all the requirements for a planar (two-dimensional) array. In other words, the above structure Accordingly, a planar array antenna with preferable performance can be obtained.

[Problem to be solved by the invention]

However, in the above-mentioned array antenna, it is necessary to provide a feeding probe 14 for each of the radiating waveguides 11, and especially when increasing the number of radiating waveguides 11 in order to obtain high gain, this is necessary. The costs for processing and assembling the parts increase proportionally, and the overall cost increases accordingly.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a waveguide slot array antenna that can feed two waveguides with one feeding probe without degrading performance. It is in.

A radiation slot is formed on one wide side of the rectangular waveguide,
A waveguide slot array antenna configured by connecting the narrow sides of the plurality of rectangular waveguides, each of the plurality of rectangular waveguides being composed of two adjacent rectangular waveguides. A window communicating between the rectangular waveguides of each set is provided in a part of the common wall of the set of rectangular waveguides, and a power supply probe for feeding power to each of the rectangular waveguides of the set is installed in the window. It is characterized by having been placed.

[For production]

According to the present invention, a part of the narrow surfaces of the two rectangular waveguides that maintain contact with each other is cut off to provide a window that communicates the waveguides with each other, and this window is provided with a window that allows the two rectangular waveguides to communicate with each other. Since we installed one power supply probe that receives power to the wave tube,
Unlike the conventional method, a feeding probe is not provided for each rectangular waveguide (and the same performance can be achieved).

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a plurality of [Embodiments] Hereinafter, embodiments of the present invention will be described in detail and specifically based on the drawings.

1, 2 and 3 show one embodiment of the invention.

In the following, members having the same functions as those in FIGS. 8 and 9 will be given the same names, and detailed explanations thereof will be omitted.

In these figures, l is a radiation waveguide (hereinafter simply referred to as a waveguide), IA is its radiation surface on which a large number of slot ICs are provided, that is, a wide surface, IB is the back surface, and ID is the adjacent guide. A narrow surface 2 which keeps the wave tubes in close contact with each other is a shorting plate, and in this example, eight waveguides 1 are arranged in parallel as shown. In addition, the two waveguides 1 are
As a set, the narrow surface ID where the waveguides 1 touch each other is cut out over a predetermined length, and as shown in FIG. 1, a total of four communicating windows 8 are formed in this portion.

On the other hand, on the back IB side, as shown in FIGS. 2 and 3, a ground conductor 7, a dielectric 6, and a microstrip branch line 5 are arranged in layers in this order, and a microstrip branch that branches into a predetermined number of electric power. forming a circuit. That is,
In this example, the microstrip branch line 5 is
It is structured so that it branches from A, sequentially through branch parts 5C and 5D, and finally reaches four branch ends 15B.

In this example as well, the actual line lengths from the power source 5A to each of the four branch ends 5B are made equal, and the electric power is equally branched. Note that impedance matching is of course achieved at the branch portions 5C and 5D.

A feeding probe 4 is connected to each branch end 5B at right angles to the back surface IB as shown in FIG. The two communicating windows 8 are respectively provided in a protruding manner at the central portion (on the axis of symmetry) of the pair of waveguides 1. In this protruding arrangement, the dielectric sleeve 3 is filled between the power supply probe 4, the ground conductor 7, and the back surface IB so that they do not come into contact with each other and are stably fixed.

Here, I would like to briefly mention the design matters related to the communication window 8.The design of the communication window 8 is based on the required performance, i.e. the frequency band to be used, the characteristic impedance and waveguide of the microstrip branch circuit. This should be done as appropriate depending on the size of the tube 1, etc., but normally the height of the communication window 8 is equal to the internal height of the narrow side IB forming wall (the inner dimension of the short side of the rectangular waveguide). good.

In addition, the length of the communication window 8 (opening length of the waveguide 1 in the tube axis direction) is a complete design requirement, but it may be approximately the inner dimension of the waveguide 1 in the wide direction. Good and stable coupling between the microstrip branch circuit and each waveguide 1 can be achieved by appropriately setting the thickness, the height and position of its protrusion into the waveguide 1 (distance from the shorting plate 2), etc. Obtainable.

In the waveguide slot array antenna having such a configuration, when a predetermined high frequency power is input from the power source 5A,
This power passes through each branch 5C and 5D and reaches each feeding probe 4 with equal power and equal phase, and finally the eight radiation waveguides 1 are excited with equal power and equal phase, and are connected to a predetermined transmitting antenna. operates as It goes without saying that this antenna functions as a receiving antenna without bringing up the reciprocity theorem.

As is clear from this example, only four feeding probes 4 are required for eight radiation waveguides 1.

Therefore, generally speaking, half the number of feeding probes as the number of radiating waveguides is sufficient, and although communication windows must be processed, the structure is simplified and manufacturing costs can be reduced. Since the number of branch stages in the branch circuit is reduced, direct losses in this part, such as radiation loss and loss due to mismatch due to variations in manufacturing accuracy, are reduced, and the line length is also shortened (because the conductor It also greatly contributes to improving reception efficiency, such as by reducing loss.

The form of the feeding probe 4 described above is well known as part of a so-called coaxial waveguide conversion structure, in which the feeding probe 4 is provided protruding into the radiation waveguide l, and its tip is connected to the waveguide. Although it is an open type that does not make direct electrical contact with the radiation surface LA of the tube 1, as shown in FIG. It is also possible to provide the radiation surface IA with a protrusion instead of protruding from the radial surface IA.

Next, a second embodiment of the present invention will be described with reference to FIG.

This example is an example in which a waveguide is used instead of a microstrip circuit in a power branch circuit called a power supply system.

In the figure, the waveguide branch circuit 25 is a rectangular waveguide that extends from the power supply pipe 25A through the branch part 25B to the first branch pipe 25G, further passes through the branch part 25D to the second branch pipe 25E. It consists of

Note that both ends of the second branch pipe 25E are closed by a short circuit plate 25F, and a through hole 25H is provided at a predetermined position on the wide surface near the short circuit plate 25F, from which the power supply probe is supported by the dielectric sleeve 23. 24 protrudes into the pipe. The other end of this feeding probe 24 protrudes into the radiation waveguide 1 as in the first embodiment.

Further, the structure of the radiation waveguide l is also completely the same as in Example 1, so the explanation thereof will be omitted here.

In such a waveguide slot array antenna structure, when high frequency power is input from the feed pipe 25A, this power is first divided into two powers of equal phase and equal power at the branch section 25B, and each of the two powers is divided at the branch section 25D. It is again divided into two powers of equal phase and equal power, and finally divided into four equal (phase, power) powers in the waveguide branch circuit 25.

These powers are transferred to the radiation waveguide 1 via the feeding probe 24.
The eight radiation waveguides 1 are excited with equal power in the same manner as in Example 1.

Although the tournament-type waveguide branch circuit shown in this example can stably distribute power with low loss, it has a more complex structure and higher cost than the microstrip branch circuit described above. According to the embodiment, the number of branching stages is reduced;
Moreover, since the number of branch ends is half of that of the conventional method, it is extremely advantageous in terms of manufacturing costs.

In actual manufacturing, both the radiation waveguide 1 and the branch circuit 2
Since the waveguides for 5 use waveguides of the same or similar size, if you try to feed power to each radiating waveguide with a feeding probe as in the past, the interval between them will become too narrow. . That is, the present invention not only reduces manufacturing costs, but also expands the degree of freedom in selecting a feeder circuit and provides an opportunity to realize a higher performance antenna.

FIG. 6 shows a third embodiment of the invention. In FIG. 6, two rectangular radiation waveguides 31 and 31 have narrow surfaces 3
They are lined up closely against the 1D wall. These waveguides 3
1, one of the wide surfaces on which a large number of radiation slots 31G are provided is called a radiation surface 31A. In this example, the waveguide 31 has a polarization plane in a direction perpendicular to the tube axis, and the radiation surface 3
It is assumed that the slot 31G is designed to radiate the main beam in a direction perpendicular to the direction 1A.

Here, 38 is a communication window formed by cutting out a wall of the narrow surface 310 between the two tubes over a predetermined length in the longitudinal center portion of these two waveguides 31 . At the center of the communication window 38 in the longitudinal direction and on the rear surface 31B side at a position on the tangent of the two waveguides 31, a feeding probe is supported by a dielectric sleeve 33, as in the two embodiments described above. 3
4 will be provided. Furthermore, the radiation surface 31A and the back surface 31B are short-circuited at the same position as the feeding probe 34 in the longitudinal direction of the waveguide 31 and at a predetermined distance apart from the feeding probe 34 in the width direction. A matching post 39, which is a matching conductor rod, is installed in each waveguide 31.

Therefore, in the waveguide slot array antenna configured in this way, when high frequency power is input from the feeding probe 34, equal power is supplied to the left and right directions of each of the two waveguides 31, 31, and a predetermined amount of power is supplied. Acts as an antenna.

Here, the role of the matching post 39 is to reflect (distribute) the power input from the feeding probe 34 to the left and right sides of the radiation waveguide 31. The position and thickness are set as appropriate depending on the shape, but the same function can be obtained with other shapes, such as a triangular metal block (not shown).

In the embodiments described so far, the feeding probe was located on the line where the two radiation waveguides forming a pair touch, that is, on the center line of the pair of radiation waveguides. An example is shown in which it is installed at a position offset from the center line.

In the present invention, the meaning of providing the power supply probe on the window shall be interpreted in a broad sense, including this example.

In the figure, reference numerals 41 and 41 designate two radiation waveguides forming a pair and configured so that the walls of the narrow surfaces 41D are in contact with each other. In the following, this contacting surface will be referred to as a contacting surface 41E.

Predetermined radiation slots are provided on the radiation surfaces (not shown) of these waveguides 41, and the figure shows a wide back surface 41B facing this radiation surface.

Further, one end of the pair of waveguides 41.41 is closed by a shorting plate 42, and the portion of the narrow side 41D of these two waveguides 41.41 that is in contact with the shorting plate 42 is
A communication window 48 is formed by cutting out a predetermined length in the longitudinal direction.

The back surface 41 of the lower one in the figure among the two waveguides 41
At B, a power supply probe 44 supported by a dielectric sleeve 43 as in the first embodiment is provided at a position separated from the contact surface 41E by L in the width direction and a predetermined distance from the shorting plate 42. .

Furthermore, in the upper part of the waveguide 41 in the figure, a reflective block 49 made of a conductor of a predetermined size is installed at a part of the corner formed by the shorting plate 42 and the outer narrow surface 41D.

In the waveguide slot array antenna configured in this way, when high frequency power is input from the feeding probe 44, the power is distributed to the upper and lower sides of the two radiation waveguides 41, but it is clear that the upper side A phase power with a phase delayed from the lower side according to the distance L from the contact surface 41E is input into the radiation waveguide 41.

Therefore, the main beam of radio waves radiated from these two radiation waveguides 41 is in a direction (in this case , the side approaching the upper radiation plate). That is, in this embodiment, the power supply probe 44 is connected to the contact surface 4.
By shifting it from 1E, it is possible to easily tilt the beam, allowing for a variety of uses.

〔Effect of the invention〕

As explained above, according to the present invention, the feeding structure in a waveguide slot array antenna is simplified, which makes it possible to increase (reduce) manufacturing costs and improve antenna reception efficiency by reducing power loss in the feeding section. In addition, the antenna can be adapted to a variety of shapes and functions, greatly contributing to expanding the practical range of the antenna.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention. FIG. 1 is a perspective view showing the structure of the array antenna partially broken away, and FIG. 2 is a perspective view showing the structure of the antenna from the back side. FIG. 3 is a partial sectional view taken along the line BB' in FIG. 2, and FIG.
A partial cross-sectional view of the embodiment; FIG. 5 is a perspective view of the configuration of the second embodiment of the present invention viewed from the back side; FIG. 6 is a perspective view showing the configuration of the third embodiment of the present invention in a broken state; FIG. 7 is a cross-sectional view of the fourth embodiment of the present invention taken along a plane parallel to the radiation surface, FIG. 8 is a perspective view of the configuration of the conventional example seen from the back side, and FIG. 9 is A of FIG. It is a partial sectional view taken along the line -A'. 1, 31.41... (radiation) waveguide, IA, 3
1A... Radiation surface, 1B, 31B, 41B... Back surface, IC, 31C.
...Slot, ID, 31D, 410...Narrow side, 2.42...
・Short circuit plate, 3, 23.33.43...Dielectric sleeve, 4,
24.34.44... Power supply probe, 5... Microstrip branch line, 5B... Branch end, 8, 28.38.48... Communication window, 25... Waveguide branch circuit, 25E...Second branch pipe. Figure 4 Figure 2 ηB-B'' Figure 3 Figure 3 Male S increases in number to 11 of 11] (by rule) Shell 11 Prisoner Figure 5 31 Afi , 4 eaves figure 9 19 pull chi r o 4j? PMIX?'↑ side 15 aq'rr
:tsnr'rmrrib diagram

Claims (1)

[Claims] 1) A waveguide slot array antenna configured by forming a radiation slot on one wide side of a plurality of rectangular waveguides and connecting narrow sides of the plurality of rectangular waveguides, A window communicating between each set of rectangular waveguides is provided in a part of the common wall of each set of rectangular waveguides each consisting of two adjacent rectangular waveguides. . A waveguide slot array antenna, characterized in that the window is provided with a power feeding probe for feeding power to each of the rectangular waveguides of the set.