JP2004221714A - Dielectric waveguide antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric waveguide antenna being a downsized slot antenna by using a dielectric waveguide for a feeder and antenna elements. <P>SOLUTION: In the dielectric waveguide antenna provided with a slot from which a dielectric material is exposed to one side of the dielectric material, the dielectric material is mounted on a printed circuit board at a position of which opposed to the slot a via-hole is formed, and the printed circuit board is joined with a metallic plate at a position of which opposed to the via-hole a through-hole is formed. Adopting an array structure wherein slots are arranged can enhance the directivity or the like. A stepped impedance structure may be attained by stacking metallic plates. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dielectric waveguide antenna which is a waveguide miniaturized by a dielectric material used in a microwave band and a millimeter wave band, and particularly relates to a structure of a radio wave radiating portion thereof.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-174541
In a microwave band or a millimeter wave band, an antenna using a hollow waveguide as a feed line is widely used. Above all, the waveguide horn antenna is the most widely used one. There are also many slot antennas provided with slots in a waveguide wall to leak electromagnetic waves in the waveguide.
[0004]
A dielectric waveguide formed by forming a conductive film on the surface of a dielectric material has the effect of shortening electromagnetic waves due to the dielectric material and does not require a thick metal wall. The size can be significantly reduced. If a dielectric waveguide is used as a feed circuit, it is possible to reduce the size and weight of the existing antenna feed structure using a hollow waveguide, and to reduce the size and cost of communication equipment in the microwave band and the moly wave band. It becomes possible.
[0005]
However, there is a large difference in the dielectric constant between the dielectric material used for the dielectric waveguide and air. Therefore, when a dielectric is used for the waveguide material, the gap between the opening (slot) portion of the waveguide and the air is increased. As a result, a large impedance mismatch occurs, which makes it difficult to emit electromagnetic waves. This greatly hinders practical use of a dielectric waveguide antenna using a dielectric.
[0006]
[Problems to be solved by the invention]
The present invention provides a dielectric waveguide antenna which is a miniaturized slot antenna using a dielectric waveguide as a feed line and an antenna element.
[0007]
[Means for Solving the Problems]
The present invention solves the above problem by combining a via hole of a printed circuit board and a through hole of a metal plate with a slot of a dielectric waveguide. That is, in a dielectric waveguide antenna having a slot in which a dielectric is exposed on one surface of the dielectric, the dielectric is mounted on a printed circuit board having a via hole formed at a position facing the slot, and the printed circuit is printed. It is characterized in that the substrate is joined to a metal plate having a through hole at a position facing the via hole.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The components of the dielectric waveguide antenna according to the present invention are as follows.
1. A dielectric waveguide having a slot: mounted on a printed circuit board such that the slot faces a via hole of the printed circuit board.
2. Printed circuit board with via holes: bonded to the metal plate so that the via holes face the slots and the through holes of the metal plate.
3. At least one metal plate with a through hole: As a result of the above, a through hole is provided at a position facing the slot.
[0009]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing an embodiment of the present invention. The dielectric waveguide 11 is fixed to the upper surface of the printed circuit board 14 by soldering or the like, and the metal plate 17 is adhered to the lower surface of the printed circuit board 14. A slot 12 formed by removing a part of the conductive film is provided on the bottom surface of the dielectric waveguide 11, and the shape of the via hole 15 of the printed circuit board 14 is made substantially equal to the slot 12, and the slot 12 is formed. Adjustment is made so that the positions of the via holes 15 substantially match. A through hole 18 is provided in the metal plate 17, and this position also matches the via hole 15 of the printed circuit board 14. With such a structure, the electromagnetic field radiated from the dielectric waveguide 11 is radiated to free space through the via hole 15 of the printed board 14 and the through hole 18 of the metal plate 17.
[0010]
2A and 2B are a plan view and a front sectional view showing a state where the dielectric waveguide antenna shown in FIG. 1 is assembled. The electromagnetic wave in the dielectric waveguide is not radiated into the air simply by providing the slot in the dielectric waveguide due to a large difference in characteristic impedance due to a difference in dielectric constant between the dielectric and the air. However, since the through-hole 18 provided in the metal plate 17 has a small dimension on the short side, it can be considered as a hollow waveguide having a low characteristic impedance. The portion of the through hole 18 operates as an impedance matching circuit between the slot 12 of the dielectric waveguide 11 and the free space, and an electromagnetic field is radiated from the dielectric waveguide 11 to the free space.
[0011]
If the metal plate 17 is used as the outer wall of the housing of the communication device, a through hole is provided in the housing of the communication device, and the printed circuit board and the dielectric waveguide are grounded to the housing of the metal plate. The housing operates as an antenna as it is. As a result, the antenna can be configured without adding any other components, and is integrated with the communication device, so that the size and cost of the communication device can be reduced.
[0012]
The dielectric and the metal used for the dielectric waveguide usually differ greatly in the coefficient of thermal expansion. Therefore, when the dielectric waveguide is directly joined to the metal plate, a stress is applied to the joint due to a temperature change. In order to prevent this, the printed circuit board functions as a cushioning material for absorbing the difference in the coefficient of thermal expansion between the metal and the dielectric. Further, it also functions as a lid for preventing electromagnetic waves from leaking from a gap caused by a difference in size between the through hole and the slot. It is not necessary that the shape of the slot and the shape of the via hole exactly match each other, and it is sufficient to prevent a gap from leaking electromagnetic waves.
[0013]
FIG. 3 schematically illustrates a magnetic field radiated from the dielectric waveguide 31 into free space. The space of the via hole 35 and the through hole 38 is connected to the slot of the dielectric waveguide 11. If the position where the slot of the dielectric waveguide is provided is less than 弱 of the guide wavelength from the short-circuit end face of the dielectric waveguide, the magnetic field intensity at the slot position is increased, and the efficiency of the antenna is increased.
[0014]
When it is desired to increase the gain and the directivity of the antenna, it can be realized by disposing a metal plate having a wider through-hole on the open surface of the through-hole. FIG. 4 is a front sectional view showing another embodiment of the present invention, in which two metal plates 47A and 47B are overlapped and the opening of the through-hole is made larger in a stepwise manner so that the opening operates like a horn. be able to. 5 and 6 show examples of the array configuration. It is known that a slot array antenna in which a plurality of slots are provided in a waveguide has an effect of enhancing the directivity and gain of the antenna. By providing a via hole array and a through hole array facing the slot array provided in the dielectric waveguide 51, an antenna having an array configuration can be easily configured, and the directivity and the gain can be enhanced.
[0015]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, since a wavelength is shortened using a dielectric substance and a thick waveguide wall becomes unnecessary, the miniaturization of a dielectric slot antenna becomes possible, and the miniaturization of a dielectric slot array antenna becomes possible. Becomes possible. The antenna element can be mounted on a printed circuit board in the device by using the outer wall of the housing of the communication device as an impedance matching device, so that the antenna and the communication device can be integrated.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing an embodiment of the present invention. FIG. 2 is a plan view thereof, and FIG. 3B is a front sectional view thereof. FIG. FIG. 4 is a front sectional view of another embodiment of the present invention. FIG. 5 is an exploded perspective view of another embodiment of the present invention. FIG. 6A is a plan view thereof, and FIG. ]
11, 31, 51: dielectric waveguide 12: slot 14: printed circuit board 15, 35: via hole 17, 47: metal plate 18, 38: through hole

Claims (3)

In a dielectric waveguide antenna having a slot where a dielectric is exposed on one surface of the dielectric,
The dielectric is mounted on a printed circuit board having a via hole formed at a position facing the slot,
A dielectric waveguide antenna, wherein the printed circuit board is joined to a metal plate having a through hole at a position facing the via hole. In a dielectric waveguide antenna having a plurality of slots in which a dielectric is exposed on one surface of the dielectric,
The dielectric is mounted on a printed circuit board having via holes formed at positions facing the plurality of slots, respectively.
A dielectric waveguide antenna, wherein the printed circuit board is bonded to a metal plate having a through hole at a position facing each via hole. 3. The dielectric waveguide antenna according to claim 1, wherein the metal plate is formed by stacking two or more metal plates, and a through hole is formed to be larger in a metal plate on a side opposite to the printed circuit board.

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