JPH0216804A - Micro strip antenna of one end-short type - Google Patents

Abstract

PURPOSE:To match electric characteristics such as the matching of a resonant frequency and that of an impedance by making the resonant frequency variable according to the intervals and the number of inter-plated through holes. CONSTITUTION:A high frequency signal inputted to a coaxial line 4 excites a feeding point 5 via a central conductor 6, and a linear polarized wave is radiated from the open peripheral end 7 of a radiation conductor element 1. The resonant frequency of a one end-short type micro strip antenna is optionally set by the plated through holes 9 which are provided on a short peripheral end 8 with the intervals of (e). When the intervals (e) are narrowed, the side length (a) are equally shortened, the resonant frequency moves to a higher level, and the resonant frequency moves to a lower level when the intervals (e) are widen.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a one-end short-circuit type microstrip antenna that is powered by a coaxial line, and in particular, by using through-hole plating as the short-circuiting method, the resonant frequency of the radiating conductor element is reduced. This relates to a structure in which the value can be arbitrarily varied.

[Conventional technology]

A short-circuited microstrip antenna using an unbalanced planar circuit resonator generally has the advantages of being small, lightweight, and low loss.

Figures 3 (a) and (b) are 1. For example, Haneishi, Suga, "Single-sided short-circuit type microstrip antenna," 1985 National Conference of the Institute of Electronics and Communication Engineers (89-5), 3-275 to 3-27
Conventional short-circuited micros (shown on page 6) I
FIG. 3 is a diagram showing an example of a J-tube antenna.

The third diagram a) is a plan view, and FIG. 3(b) is a sectional view.

In the figure, (1) is a radiation conductor element made of a rectangular one-end short-circuited planar circuit with side lengths a and b, (2) is a dielectric substrate (relative permittivity ε1, thickness h) that is sufficiently thin compared to the wavelength, ( 3) is the ground conductor plate, (4) is the coaxial line of the input terminal, (6) is the center conductor of the coaxial line, and (5) is the center conductor (6) of the coaxial line (4) to the radiation conductor element (1). The feeding points to be connected are (7) an open peripheral end from which radio waves are radiated, and (8) a short-circuit peripheral end which connects the radiation conductor element (1) to the ground conductor plate (3).

Next, the operating principle will be explained.

When microwaves are fed from the feed point (5), stain waves are radiated to the open peripheral end (7). The example shown in FIGS. 3(a) and 3(b) operates as a linearly polarized wave.

The resonant frequency fQ of the fundamental mode of the IJ tube antenna (one end short-circuited micros) is mainly determined by the radiation conductor element (
It is determined by the side length a of 1) and the dielectric constant ε of the dielectric substrate (2). Also, what is the frequency bandwidth of 9?

It is mainly determined by the dielectric constant ε1 and thickness h of the dielectric substrate (2), and the smaller ε1 and the larger h the wider the band, but it is important to prevent the generation of higher-order modes. Therefore, there is a limit to the selection range of the thickness h, and the frequency band of the one-end short-circuited microstrip antenna that has been put into practical use is about several inches, as shown in FIG.

The feed point impedance is the feed point (5) at the open peripheral end (
7) and c = 0, the impedance is high, but as the feed point (5) approaches the short-circuit peripheral end (8) of the radiation conductor element (11), the impedance of the feed point gradually decreases. The dimension C is selected so as to achieve impedance matching with the coaxial line (4).

In addition, the 9 dimension d is set to prevent the generation of cross-polarized components.
b/z.

[Problem to be solved by the invention]

Since the conventional one-end short-circuited microstrip antenna is configured as described above, the dimensions of the one-end short-circuited microstrip antenna are important from the viewpoints of impedance matching, cross-polarization suppression, and resonant frequency.

Since the shape and position of the coaxial line are limited, when manufacturing and using a large number of single-end short-circuited microstrip antennas, the electrical characteristics of each microstrip antenna may be affected by variations in the permittivity of the dielectric substrate used and workability. There were issues such as differences due to tolerances.

Further, since the conventional one-end short-circuit type microstrip antenna essentially has a narrow band, it is difficult to match the resonant frequency.

This invention was made to solve the above-mentioned problems, and it is possible to eliminate variations in the dielectric constant of the dielectric substrate and workability tolerances without changing the dimensions and shape of the radiation conductor element or coaxial line. It is an object of the present invention to obtain a one-end short-circuited microstrip antenna that enables matching of electrical characteristics such as resonant frequency matching and impedance matching even when the antenna is added.

[Failure to solve the problem]

In the one-end short-circuit type microstrip antenna according to the present invention, the short-circuit peripheral end (8) side is connected to the short-circuit peripheral end (8) connecting between the radiation conductor element +11 and the ground conductor plate (3) at an arbitrary interval. A plurality of through-hole platings are arranged, and the resonant frequency of this one-end short-circuited microstrip antenna is varied by changing the spacing between the through-hole platings and the number of through-hole platings, and matching to a desired frequency is achieved.

[Effect]

In the one-end short-circuit type microstrip antenna of the present invention, a plurality of through-hole platings are used to short-circuit between the radiation conductor element fil and the ground conductor plate (3) on the side opposite to the open peripheral end (7), and the through-hole plating is By changing the number and spacing, the resonant frequency of the short-circuited microstrip antenna can be adjusted to the desired value without changing the side length a of the radiating conductor element (11) or the dielectric constant ε of the dielectric substrate (2). It is possible to match the frequency of

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1(a), (b), and (C) are views showing one embodiment of the present invention, FIG. 1(a) is a plan view, and FIG. 1(b) is a plan view.
is a sectional view, and FIG. 1(c) is a diagram showing an isotonic circuit. In the figure.

(11 to (8) are exactly the same as the conventional one-end short-circuited microstrip antenna mentioned above. (9) is.

The conventional one-end short-circuit type microstrip antenna is connected to the ground conductor plate on the entire surface at the short-circuit peripheral end (8). Holes are made at 1 interval e through hole plating to connect with the ground conductor plate. .

FIG. 2 is a diagram showing changes in the resonant frequency of the one-end short-circuited microstrip antenna when the number of through-hole platings (9) is changed.

The operation of one embodiment of the one-end short-circuit type microstrip antenna according to the present invention configured as described above will be described.

The high frequency signal input to the coaxial line (4) of the input terminal is
The feed point (5) is excited via the center conductor (6), and linearly polarized radio waves are radiated from the open peripheral end (7) of the radiation conductor element (1). Radiation conductor element (feed point for ++ (5
) is determined from the viewpoint of impedance matching and cross-polarization suppression, similar to the conventional short-circuited microstrip antenna. On the other hand, one end shorted type micros l-I
The resonant frequency f of the J-tube antenna is.

A plurality of through-hole platings (9) provided at intervals of e on the short-circuit peripheral edge (8) without changing the side length a of the radiation conductor element (1) and the dielectric constant ε1 of the dielectric substrate (2) Can be set arbitrarily. When the number of through-hole platings (9) is increased and the interval e is narrowed, the side length a of the radiation conductor element (1) becomes equivalently shorter, and the resonance frequency increases to a higher frequency as shown by the dotted line in Figure 2. If the number of through-hole platings (9) is reduced and the interval e is widened, the side length a of the radiation conductor element (1) becomes equivalently longer, and the resonant frequency becomes lower as shown by the points in Figure 2. It is possible to change the resonant frequency by changing the frequency.

In the above embodiment, the through-hole plating (9) is shown in a circular shape, but it may be formed in a square shape. In the above embodiment, one dielectric substrate (2) is used between the radiation conductor element (++) and the ground conductor plate (3), but it may be composed of multiple dielectric substrates. The same effects as in the above embodiment can be obtained.

Furthermore, in the above embodiment, one end short-circuit type micros) I
Although the shape of the J-tube antenna has been described using a rectangular radiating conductor element (1), the same effect can be obtained with a radiating conductor element (1) having a square, a circle, or an arbitrary shape.

〔Effect of the invention〕

As described above, according to the present invention, by arranging a plurality of through-hole platings (9) at the short-circuit peripheral end (8) and changing the number and interval of the through-hole platings (9), the radiation conductor element ( The side length a of 1) and the relative permittivity of dielectric substrate (2)
(+: The resonant frequency can be changed without changing the rate ε, so even if the resonant frequency changes due to variations in the dielectric constant of the dielectric substrate and tolerances in workability, through-hole plating (9) ) By changing the number and spacing of the antennas, it is possible to obtain a one-end short-circuited microstrip antenna that can be matched to a desired resonant frequency.

[Brief explanation of the drawing]

Figures 1 (a), (b), and (C) are diagrams for explaining one embodiment of the present invention, and Figure 2 is a one-end short-circuit type microstrip when the number and spacing of through-hole plating are varied. A diagram showing the characteristics of the resonant frequency and return loss of the antenna. Figure 3 (a) and (+)) are diagrams showing an example of a conventional one-end shorted microstrip antenna. Figure 4 is a conventional one-end shorted microstrip antenna. FIG. 3 is a diagram showing the characteristics of the resonant frequency and return loss of the antenna. In the figure, (1) is a radiation conductor element, (2) is a dielectric substrate, (
3) is the ground conductor plate, (4) is the coaxial line, (5) is the feed point, (6) is the center conductor, (7) is the open peripheral edge, (8) is the shorted peripheral edge, (9) is the through hole. It is plated. Note that in FIG. 1, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A radiation conductor element with a plane circuit short-circuited at one end to a grounded conductor plate is provided on a dielectric substrate that is thinner than the wavelength, and a coaxial line for power supply is provided on the back of the opposing grounded conductor plate. A short-circuit type microstrip antenna, characterized in that the resonant frequency of the microstrip antenna is made variable by the number and spacing of through-hole plating used to short-circuit between the ground conductor plate and the planar circuit. antenna.