JPH0365805A - Waveguide antenna - Google Patents

Abstract

PURPOSE:To improve the working accuracy and to reduce the working time by adopting a cover with a slot formed to a metallic thin plate or a laminated body comprising a metallic thin plate and an organic base material thereon by the chemical etching for the cover of a radiation part. CONSTITUTION:A radiation part is assembled by a bottom comprising a conductor block 3 provided with plural parallel slots 4 being guide lines and a lamination board for a printed circuit board, or a board for a flexible printed circuit board, or a cover 2 in which plural slots 1 being an exist of a radiation wave are provided to a metallic thin plate or a foil through mechanical and electrical connection. Then the cover 2 of the radiation part is formed with slots 1 with the chemical etching method to a metallic thin plate or a laminator comprising a metallic thin plate and an organic base. Thus, the design of the slots 1 of complicated shape is facilitated and the processing is easily implemented, the working error from the design dimension is less and a waveguide antenna with a high efficiency and a high tilt angle is obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an antenna for receiving radio waves in the microwave band, and more specifically, the present invention relates to an antenna for receiving radio waves in the microwave band. This invention relates to a waveguide antenna that can obtain a high tilt angle.

[Conventional technology]

Conventionally, antennas formed by forming an array of slots on a waveguide have already been put into practical use in fields that require high performance, but they are generally manufactured by machining the waveguide.
High processing accuracy was required, and the cost was also high.

The conventional waveguide antenna, as shown in Fig.
A slot (25) is inserted into the RJ-140 standard waveguide (24).
) is attached by machining. Structurally, it is composed of a power feeding section (22) that supplies radio waves to a radiating section (23), and a radiating section (23) that radiates radio waves.

The characteristics of a waveguide antenna are the transmission loss of the waveguide (-0, 3
dB/m or less) and high antenna efficiency. Furthermore, the radiation angle e that the radiation wave (27) radiated from the slot makes with respect to the radiation part (23) is λ, which corresponds to the free space wavelength. , 7216% when the wavelength inside the waveguide is λ
Using F, it is expressed as e-3IN-'(λ./λ,), and when using a WRJ-140 waveguide, the frequency is 12GH.
In z, it is about 38#. The radiation angle e is called the tilt angle, and when receiving satellite broadcasting, etc., the elevation angle relative to the satellite with a normal parabolic antenna is around 38° (Kanto region), whereas with a waveguide antenna, the angle of elevation relative to the satellite is already around 38°. Because it has a corner, there is no need to tilt the antenna body significantly.

However, in the conventional method, the waveguide was processed by mechanical processing such as cutting and punching, which caused problems such as difficulty in increasing processing accuracy and a long processing time.

[Problem to be solved by the invention]

In view of these problems with conventional waveguide antennas, the present invention makes it possible to easily design and process slots with complex shapes by adding ingenuity to the structure and processing method, and the design dimensions can be reduced. The purpose of the present invention is to provide a waveguide antenna with a small processing error, high efficiency, and a high tilt angle (means for solving the problem). a radiating part formed by assembling a bottom part made of a conductor provided with a plurality of grooves, a lid made of a conductor provided with a plurality of slots, and a bottom part made of a conductor provided with grooves serving as a distribution waveguide. It basically consists of a power feeding part assembled with a lid made of a conductor, and the lid of the radiation part is a thin metal plate or a laminate of a thin metal plate and an organic base material with slots formed by chemical etching. This is a waveguide antenna characterized by the following.

Hereinafter, the waveguide antenna of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a diagram for explaining an embodiment of a radiating section of a waveguide antenna according to the present invention. The radiation part is a conductor block (3) provided with multiple parallel grooves (4) that serve as waveguides.
The bottom part consists of two slots for the printed circuit product value (1)
It is assembled by mechanically and electrically connecting the lid (2) provided with the lid (2).

The material of the conductor block (3) used here is a sheet metal processed metal plate, or a plastic molded member with grooves formed by a method such as injection molding or sheet aging molding, and conductive treatment such as plating on the surface. The type of metal used when sheet metal processing a metal plate is preferably a metal with high conductivity, such as copper or aluminum. Also, when conducting conductive treatment on the surface of a plastic molded member, Electroless plating methods, metal spraying methods, conductive coating methods, etc. can be used, but the thickness of the conductive layer is preferably about 10 um in consideration of the penetration thickness of microwaves. When performing electroless plating, it is easier to plate. It is preferable to use plastic, such as ABS resin.

Furthermore, when a printed circuit laminate or a flexible printed circuit board is used as the material for the lid (2) in which the slot (1) is formed, the slot (1)
) dimensions must be corrected, but since the base material remains in the slot, the inside of the waveguide is isolated from the outside air, and the metal inside is protected from moisture, water, harmful gases, etc. This is convenient. Furthermore, it is also possible to improve weather resistance by filling the inside of the waveguide with an inert gas such as nitrogen, if necessary.

The printed circuit laminate or flexible printed circuit board used as the material for the lid (2) preferably has electrical properties such as low dielectric constant and low dielectric loss tangent, for example, in the microwave band. It is preferable that the dielectric constant in the Ku band is 4.0 or less and the dielectric loss tangent is 2.0×10'' or less.

The material is not particularly limited as long as it satisfies the above conditions.When the dielectric constant becomes 4.0 or more, multiple reflections in the base material increase, and as the dielectric loss tangent increases, the loss increases. , characteristics less than the above values are required.

Further, the metal thin plate or foil used as the material for ml(2) preferably has a thickness of 1100 mm or less.

If the thickness exceeds 100 μm, the impedance of the slot will change by the increase in thickness, which will have a greater effect on the radiation characteristics of the antenna, which is not preferable.

A metal plate forming the conductor block (3) of the radiation section, and M
The DC conductivity of the conductor such as a thin metal plate or foil for forming the slot (1) in (2) is 4.0×10'
(S/m) or more and the center line average roughness Ra specified by JIS BO601 is preferably 1 μm or less. If the DC conductivity is 4.0X10' or less, conductor loss will increase, and Ra is 1 μm or more. If so, conductor loss at high frequencies will increase, so materials with the above characteristics are preferable.
Conversely, any metal can be used as the material as long as it satisfies the above characteristics. A desired slot pattern is formed using a resist or the like on a laminate, a substrate, or a thin metal plate or foil having the above characteristics, and then processed by chemical etching. Methods for forming the slot pattern resist include screen printing, photolithography using a photoresist, etc., and any method may be used.

Any of the following methods may be used to join the conductor block (3) that forms the bottom of the radiation section and the lid (2), which is a printed circuit laminate or the like with slots (1).

(1) Method of bonding with conductive adhesive (6) [Figure 1 (b)] The conductive adhesive (6) used here has a volume resistivity of 5.0×10-' (Ω, CI) or less. It is preferable that there is a certain amount; if it is more than that, losses will increase and efficiency will decrease.

(2) Screw (7) or crimping by heat caulking (first
Figure (C)] In this case, apply sufficient pressure to the joints to bring them into contact. At this time, the contact resistance is 5. It is preferable to adjust the pitch to OX 10 (Ω, CI) or less. Also, the pitch interval of the screws (7) and heat caulking is 1/1, where λ is the wavelength inside the waveguide to be formed. A pitch of 4λ is preferable because it can prevent reflections at discontinuous parts due to the pitch interval of the screw (7) and heat caulking.

Next, the feeding part a of the waveguide antenna in the present invention is inserted,
As shown in Fig. 2(b), the bottom of the conductor block (8) with a groove (9) to serve as a waveguide and the lid 0Φ made of conductor are assembled and installed at the bottom of the tank, as shown in Fig. 2(C). As shown, it is connected to the radiation section θ0 to form an antenna. An example of the shape of the grooves (9) is one in which seven Y-branched grooves are combined as shown in FIG. 2(a), and an eight-distribution distributor is formed at the bottom of the tank.

The conductor block (8) used here is obtained by molding plastic by injection molding, cutting, etc., and forming a conductive layer on the surface by metal spraying, electroless plating, conductive coating, etc. It will be done. The thickness of the conductive layer is preferably about 10 μm in consideration of the penetration thickness of microwaves. Also, when the plastic used for the conductor block (8) is conductive treated by electroless plating, it is preferable to use ABS resin, etc., which is easy to plate. It is preferable to use

Hereinafter, the waveguide antenna based on the present invention will be specifically explained based on Examples and Comparative Examples.

〔Example〕

A bottom part 07) having 16 grooves 06) as shown in FIG. 2
．． Maω was made using a printed circuit laminate made by laminating a heat-resistant polyolefin with a thickness of 0.8-cm and a rolled m-oxygen W4 foil with a thickness of 35 μm at a frequency of 0×10-co(12C; Hz). An array of 30 slots OgJ in the length direction of grooves 0ω and 16 slots in the lateral direction was formed by chemical etching at positions corresponding to the upper portions of the 16 grooves 00 using a photolithography method. The bottom part 07) and the lid aω were adhered using a conductive adhesive having a volume resistivity of 5.0×10 −′ (Ω, CI), and the radiation part of the antenna was attached to the bottom of the tank.

Note that both the rolled oxygen-free copper foil and the electrolytic w4'N were excited in the same phase in the middle, and the ends of the radiation parts were short-circuited.

[Comparative example]

Sixteen WRJ140 waveguides (21) with slots QI formed by machining were connected laterally as shown in Fig. 3) to connect the radiating part of the planar antenna to the bottom of the tank. The shape of the slot (to) was designed to have the same characteristics as in the example, and each waveguide (21) was subjected to uniform in-phase excitation.

Table 1 shows the slot design method and processing dimensions for each of the examples and comparative examples, and it can be seen that according to the present invention, the errors in processing dimensions are small. Note that the dimensions indicate the length and width of the cross-shaped slot, and the design dimensions include corrections for the wall thickness of the dielectric and waveguide.

Further, the measurement results of the radiation characteristics as an antenna are as shown in Table 1. The measurement method is based on the Japan Electronics Industry Association standard CP.
-604-03r Satellite Broadcast Receiving Antenna Test Method (Electrical Properties II) The gain of the antenna of the example is shown with the gain of the waveguide antenna of the comparative example set to O.

Table 1

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining one embodiment of the radiation section of the waveguide antenna according to the present invention, and (a) is a perspective view showing the configuration;
(B) is a lateral sectional view, and (C) is a partial top view. 21 is a diagram illustrating the power feeding part of the waveguide antenna according to the present invention, (a) is a groove (waveguide) formed in a conductor block.
(b) is a sectional view of the end portion, and (C) is a diagram showing the entire antenna configured by assembling the radiating part and the feeding part. FIG. 3 is a diagram showing an example of the present invention and a comparative example, in which (a) is an example of the waveguide antenna radiation part according to the present invention, and (b) is a diagram showing a waveguide with slots formed by machining. This is a comparative example in which a radiating section of a planar antenna is constructed by connecting the antennas in different directions. Also, Figure 4 is a diagram for explaining a conventional waveguide antenna, in which (a) is an overall schematic diagram, (b) is a top view of one waveguide, and (c) is a diagram of (c). FIG. 3(d) is a cross-sectional view taken along line AA' of FIG.

Claims (1)

[Claims] (1) A radiating part made by assembling a bottom made of a conductor with multiple parallel grooves to serve as a waveguide and a lid made of a conductor with multiple slots, and a groove to serve as a distribution waveguide. It basically consists of a power feeding section assembled with a bottom made of a conductor and a lid made of a conductor, and the lid of the radiation section is formed by chemically etching a thin metal plate or a laminate of a thin metal plate and an organic base material. A waveguide antenna characterized in that a slot is formed by a method.