JPS58215807A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To miniaturize an antenna with a simple constitution, by forming a straight or curved slit in symmetry to a straight line connecting a center of a patch antenna and a feeding point, for decreasing the resonance frequency. CONSTITUTION:The straight or curved slits 6a-6c are provided symmetrically to an axial line 5 tying the center of a patch antenna 1 and the feeding point 3 in the edge direction therefrom. Further, slits 7a-7c are provided respectively from the edge direction to the axial line 5, and the respective slits 6a-6c or 7a-7c are formed on a dielectric 2 together with the antenna 1. A slit 8 is provided at the opposite side of the feeding point 3 to the center of the antenna 1, a slit 9 is provided between the center and the feeding point 3, and a slit 10 is provided at the opposite side of the center of the antenna 1 and the feeding point 3. Thus, the resonance frequency is decreased and the microstrip antenna is miniaturized with a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microstrip antenna, and particularly aims to reduce the size of a punch antenna to realize overall miniaturization.

A conventional microstrip antenna is shown in Figures 1 and 2.
As shown in the figure. Figures 1 (a) and (b) are a top view and a cross-sectional view of a microstrip antenna in which the patch antenna 1a is rectangular, and Figures 2 (L) and (b) are in which the patch antenna 1b is circular. FIG. 3 is a top view and a cross-sectional view of a microstrip antenna. To explain this, patch antennas 1a and 1 are placed across dielectrics 2a and 2b.
b and conductor ground plates 4a and 4b are connected to each other, and power is supplied from the feed point 3 to operate as an antenna. Patch antennas may have shapes other than those shown in the two figures, such as squares and ellipses.

The dimensions of the square patch antenna are d−C/(2f0εr′
A) is given by The dimensions of the circular patch antenna are:
It is given by a=(t841Xc)/(2πfoεr%).

Here, d is the length of the edge parallel to the straight line connecting the centers of punch antennas 1a and 1b and feeding point 3, and a is the radius of the circular patch antenna. Here, C is the speed of light, ε is the resonant frequency, and ε is the relative permittivity of the dielectric. From these equations, the dimensions of the antenna become smaller as the resonance frequency 10 becomes higher or as the dielectric constant of the dielectric material becomes higher. However, high dielectric constant materials generally have a high specific gravity, and their thickness must be increased in order to obtain a sufficient band, making them impractical in terms of weight.

The present invention realizes miniaturization of a microstrip antenna by providing a slit in a patch antenna. That is, according to the present invention, the resonant frequency can be lowered by providing the liner 1 symmetrically with respect to the straight line connecting the center of the patch antenna and the feeding point. It is clear that lowering the resonant frequency with a punch antenna of the same size and reducing the size of the punch antenna with the same resonant frequency mean the same thing.

The embodiment will be described below with reference to the drawings, but since the conductor ground plate is the same as the conventional example described above, illustration thereof will be omitted. Figure 3 (a), (b) l (C) l (
d) l (e) + (f) shows the shape of the slit using a rectangular punch antenna as an example. Surin)
6a is a linear internal slit provided toward the edge from the axis 51 connecting the center of the punch antenna 1 formed on the dielectric body 2 and the feeding point 3; This is a linear external slit provided from the edge toward the axis 5, and both are basic slit shapes. The slits 6b and 6c and the slits 7b and 7C are curved versions of the slits 6a and 7a, respectively.

FIG. 4 is a diagram showing the positions of the slits, taking a rectangular punch antenna as an example. The slit 8 is provided on the opposite side of the feeding point 3 with respect to the center of the punch antenna 1,
The slit 9 is provided between the center of the patch antenna 1 and the feed point, and the slit 10 is provided on the opposite side of the center of the patch antenna 1 with respect to the seven feed holes.

The shape of the slit and the position of the slit explained using FIGS. 3 and 4 apply similarly to microstrip antennas of other shapes such as circular patch antennas.

By increasing the length of the basic slit mentioned above, it is possible to further lower the resonance frequency, but by appropriately combining these slits,
Resonant frequency can be lowered.

FIG. 5 shows an example of the combination using a rectangular patch antenna. The embodiment shown in FIG. 6 consists of four internal slits 6 and two external slits 7. Such a combination.

Although there are countless examples, it can be realized by combining a patch antenna of a desired size with an appropriate slit for a particular resonant frequency.

FIG. 6 shows still another embodiment of the present invention in which the combination of slits shown in FIG. 5 is applied to a circular patch antenna, and corresponding parts are given the same reference numerals.

As described above, the present invention can realize a small microstrip antenna with a simple configuration, and furthermore, when a material with a relatively low specific gravity and low dielectric constant is used, further weight reduction is possible. It has several features.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are a top view and a cross-sectional view of an example of a conventional microstrip antenna, and Figures 2 (a) and (
b) is a top view and a cross-sectional view of another example of a conventional microstrip antenna;
, (e) and (() are diagrams showing examples of the shapes of slits formed according to the present invention, and FIGS. 4, 5, and 6 are plan views of each embodiment of the present invention, respectively. 1. 00 Patch antenna, 2...---Induction body, 3
0...0 feeding point, 5----...++e axis, 6a, 6b
, 6c. 6, Ryo a, 7 b, 7 C, 71+1111@
@I+Slit. Name of agent: Patent attorney Toshio Nakao and 1 other person,
Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A microstrip antenna characterized by forming a linear or curved slit symmetrically with respect to a straight line connecting the center of the punch antenna and the feeding point.