JP2003078337A - Laminated antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate leakage of signals, to improve transmission efficiency of signals and to improve gains. SOLUTION: A laminated antenna is provided with a combination layer 20 having a photonic bandgap structure of two-dimensional layout in which inputted signals are electromagnetically excited, slot portions 21 are provided on a metallic coating 21a, and a plurality of appropriate bore portions 21b are formed at prescribed intervals, and a radiating layer 10 for radiating the signals from the layer 20 as electromagnetic waves. The respective layers are formed into a laminated structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated antenna capable of eliminating signal leakage, improving signal transmission efficiency and gain.

[0002]

2. Description of the Related Art Recently, in a microwave / millimeter wave region, when a dielectric substrate is used for a planar circuit or an antenna, unnecessary radiation from an edge of a finite substrate due to surface waves and a limitation such as low gain appear. Therefore, efficient microwave,
There has been active research on transmitting millimeter waves or optical signals by a new technique called a photonic band gap (hereinafter referred to as “PBG”).

The PBG structure is an artificial crystal that does not allow the propagation of electromagnetic waves in a certain frequency range. This has been proposed as a new technology since their similarities were discussed, such as being associated with the crystal arrangement and band theory found in solid state physics. As a representative example of the PBG structure, FIG. 7 shows a two-dimensional structure in which dielectric rods are arranged in the air, and FIG. 8 shows a two-dimensional structure in which holes are provided in the dielectric.

[0004]

These PBG structures can be mainly applied to microwave / millimeter wave planar circuits / antennas. In the microwave / millimeter wave region, since the planar circuit and the antenna are manufactured on a finite substrate, there are problems such as lowering of gain and deterioration of characteristics due to the influence of unnecessary radiation due to surface waves. The PBG structure is considered to be an extremely effective technique for this problem, and various application examples have been reported so far. However, it has been pointed out that the conventional PBG structure is difficult to manufacture because it has periodic holes in the dielectric, but requires extremely precise machining technology due to its short wavelength in the light region. As one solution to such a problem, since the PBG structure is applied to a microwave flat substrate, it is composed of a metal coating a and a dielectric b as shown in FIG. An example has been reported in which the portion c is achieved by a method of removing the ground conductor by etching. In any case, there is a demand for an antenna substrate or the like that eliminates signal leakage and improves signal transmission efficiency.

[0005]

Therefore, as a result of intensive studies by the inventor to solve the above problems, the present invention electromagnetically excites an input signal to form a slot portion on a metal film. A coupling layer having a two-dimensionally arranged photonic bandgap structure with a plurality of appropriate perforations formed at a predetermined distance, and a radiation layer for radiating a signal from the coupling layer as an electromagnetic wave, By solving the above-described problems, it is possible to eliminate signal leakage, increase signal transmission efficiency, and increase gain by using a laminated antenna in which each layer has a laminated structure.

Further, in the above structure, the coupling layer has two slots, and the two are parallel antennas arranged at a predetermined distance from each other so that the signal transmission efficiency can be further improved. It is possible to solve the above problems.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a structure diagram of a laminated antenna having three layers. Circuit layer 30 from the bottom
A coupling layer 20 having two slot portions 21a and a radiation layer 10 having a patch antenna portion 10a.

The circuit layer 30 is a passive circuit and is a functional layer for transmitting an input signal. Further, the circuit layer 30 is provided with an amplifying means 31 as an active circuit, if necessary.
May be provided. The amplifying means 31 includes a microstrip line 31a and a field-effect transistor (FET) formed on the microstrip line 31a.
r: A power amplification unit (power amplification circuit) 31b including a field effect transistor) and a patch resonance circuit unit 31c may be provided.

As shown in FIGS. 1 to 3, the coupling layer 20 is composed of a metal film 21 as a metal ground plane plate and a dielectric substrate 22 which is the lower surface of the metal film 21. The metal coating 21 is provided with at least one slot portion 21a, and preferably two slot portions 21a. The two slot portions 21a, 21a are formed so as to be arranged in parallel with each other at a constant distance. A plurality of two-dimensional PBs are provided so as to surround the slot portion 21a.
A G structure is formed. Specifically, the perforated portions 21b of the perfect circular portion (radius r) are equilaterally triangular with a distance of equal intervals p, and two or three rows are perforated as a matrix. The metal film 21 is made of a metal foil such as copper,
The slot portion 21a and the perforated portion 21b are formed by etching the substrate made of the metal foil. Further, as long as the substrate can be peeled off, dissolved or removed, the etching process is not limited and it can be formed by any means.

The radiation layer 10 is provided with a patch antenna section 10a for appropriately transmitting electromagnetic waves for power transmission, at an appropriate position on the surface of the substrate, preferably near the central position.
Further, two slot portions 21a, 21a of the lower coupling layer 20 are arranged on the back surface sandwiching the substrate from the patch antenna portion 10a so as to be aligned with both end positions of the patch antenna portion 10a. (See FIG. 1).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a laminated active integrated amplifier antenna using a two-dimensional PBG structure, in which the circuit layer 30 is provided with an amplifying means 31 as an active circuit, is used. The layer 20 is a soft substrate (25NG0310CSSA: relative dielectric constant 3.25, dielectric thickness 0.787 [mm]) as the dielectric substrate 22, and a rolled copper foil (0.
018 [mm], tan δ 0.0025). The input signal is filtered by the patch resonance circuit section 31c, amplified by the amplifying means 31, and passed through the slot section 21a of the coupling layer 20 to the patch antenna section 1 of the radiation layer 10.
Emitted by 0a. By providing a two-dimensional PBG structure by etching in the coupling layer 20 portion of this active integrated antenna, signal leakage is eliminated in the plane direction (X, Y direction) of the coupling layer 20, and the vertical direction (Z
Signal is transmitted only in the direction), the efficiency of the slot portion 21a is improved, and signal transmission with less leakage is possible.

Return loss of the antenna of the embodiment
Loss) measurement results are shown in FIG. 4, and antenna pattern measurement results are shown in FIG. 5 (A). It is considered that the theoretical value (Computed) and the experimental value (H-plane) are almost the same in the antenna pattern. FIG. 5B shows a laminated active integrated amplifier antenna as a prior art as shown in FIG. 6, in which the metal film 21 of the coupling layer 20 has two slot portions 21a and 21a which are constant with each other. They are arranged in parallel at a distance, and the data when this known technique is used is shown in FIG. 5 (B).

Since all of the coupling layers 20 having the PBG structure are achieved by etching, they are relatively easy to manufacture and have a dielectric laminated structure.
Due to the wavelength shortening effect, there is an advantage that the antenna and the entire circuit can be downsized. Furthermore, this PBG structure acts to suppress surface waves, and can improve the characteristic deterioration that becomes a problem when using a finite substrate.

[0014]

In the laminated antenna according to the present invention, by providing the PBG structure in the coupling layer 20 portion, the slot portion 21a is made highly efficient, and signal transmission with less leakage can be performed, so that the signal transmission efficiency is improved. You can increase the gain. Furthermore, this PBG structure acts to suppress surface waves, and can improve the characteristic deterioration that becomes a problem when using a finite substrate.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of main components of the present invention.

FIG. 2 is a plan view of a bonding layer.

FIG. 3 is a sectional view of a bonding layer.

FIG. 4 is a graph of a litter loss measurement result for the present invention.

5A is an antenna pattern measurement result graph of an active integrated antenna provided with a laminated antenna having a PBG structure of the present invention, and FIG. 5B is an antenna pattern measurement result graph of an active integrated antenna according to a conventional technique.

FIG. 6 is an exploded perspective view of main members of a conventional active integrated antenna.

7A is a perspective view of a two-dimensional structure of a conventional PBG structure in which dielectric rods are arranged in the air, and FIG. 7B is a partially enlarged plan view of FIG. 7A.

FIG. 8 is a perspective view of a conventional PBG structure having a two-dimensional structure with holes provided in a dielectric.

FIG. 9 is a perspective view of a conventional two-dimensional PBG structure by etching.

[Explanation of symbols]

10 ... Radiant layer 20 ... Bonding layer 21 ... Metal film 21a ... slot part 21b ... perforated part

Claims (2)

[Claims] 1. A photonic bandgap structure having a two-dimensional array in which an input signal is electromagnetically excited, a slot is formed on a metal film, and a plurality of appropriate perforations are formed at a predetermined distance. A laminated antenna comprising: the coupling layer and a radiation layer that radiates a signal from the coupling layer as an electromagnetic wave, and each of the layers has a laminated structure. 2. The laminated antenna according to claim 1, wherein the coupling layer has two slot portions, and the two slot portions are arranged in parallel at a predetermined distance.