JPS59126304A - Shared microstrip antenna for two frequency bands - Google Patents

Abstract

PURPOSE:To obtain a shared antenna for two frequency bands by arranging radiation elements which resonate at respective transmission/reception frequencies on both sides of an array of through holes or pins as a boundary. CONSTITUTION:Rectangular elements which are about L1/2 and L2/2 long are provided on both sides of the through array or pin array 5 as a boundary. Those elements resonate at specific resonance frequencies. This figure shows that both elements are fed, but while only one element is fed, the other element can be excited by utilizing the coupling by the pin array 5 between the elements. At this time, the coefficient of the coupling is determined by intervals of the through hole or pin array 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microstrip antenna that has a small and simple configuration and can be used in two frequency bands.

A microstrip antenna usually has narrow band characteristics, and in order to perform shared transmission and reception when used for communication, it is necessary to be able to use it in two frequency bands for transmission and reception. An example of conventional common use of two frequency bands is shown in FIGS. 1 and 2. FIG. 1 shows radiating elements having different resonant frequencies arranged side by side, and FIG. 2 shows radiating elements having different resonant frequencies stacked one on top of the other. In Figure 1 and Figure 81\2 (a) Φ), 1 is a receiving radiation element, 2 is a transmitting radiation element, 3 is a dielectric plate, 4 is a metal substrate, 5 is a power supply pin, 7 is a connector, 8 is an earth pier, and 9, 9a, 9b, and 9c are quarter wavelength transformers.

In the case of Figure 1, the area occupied by the elements is twice that of a single frequency case, and when a large number of these elements are used to construct an array antenna, the element arrangement is limited and the feeding circuit is complicated. be.

In the case of Fig. 2 (a) Φ), there are no problems with the complexity of the element arrangement or the feeding circuit, but there is the design difficulty of duplicating the elements, which is a characteristic of the narrow microstrip antenna. They often lack the advantage of being constructed from a single printed circuit board.

In order to eliminate these drawbacks, the present invention provides a microstrip antenna for two frequency bands that achieves dual frequency sharing by arranging radiating elements that resonate at each transmitting and receiving station wave number with through holes or rows of bins as boundaries. It is something to do.

The present invention will be explained in detail below.

FIGS. 3(a) and 3(b) are a plan view and a cross-sectional view showing the electric field distribution of the fundamental mode of a rectangular microstrip antenna. In the figure, 3 is a dielectric plate, 4 is a metal substrate 5 is a power supply pin, 6 is a metal plate, 7 is a connector, and 8 is a ground bin.

The arrows indicate the electric field distribution.

Here, L is given by the following equation.

Note that C represents the speed of light, f represents the resonance frequency, and εr represents the relative dielectric constant. In the case of the fundamental mode, the plane I[1-
The electric field at Illa is zero, and the same characteristics can be obtained in the configurations shown in FIGS. 4(a) and 4(b) by providing a through-hole row or a pin row on the Ill-Illa plane. This uses the image effect produced by providing a ground plane on the In-Illa plane.

The present invention utilizes this effect, and an embodiment is shown in FIG. 5, in which (a) is a plan view and (b) is a sectional view.

With the through-hole row or pin row as the boundary, one side of the boundary and the other side have different lengths of approximately L++/2 +
A square element of L2/2 is provided. Each element resonates at a resonant frequency given by the following equation.

= 3- As is clear from the comparison between FIG. 3 and FIG. 5, it is possible to realize two frequencies with approximately the same size.

Although Fig. 5 (a) and (b) show the case where power is supplied to each element, as shown in Fig. 6 (a) It is also possible to excite the other element using coupling via. At this time, the coupling coefficient is determined by the spacing between the through hole rows or pin rows.

FIG. 7(a) shows an example of measuring the VSWR characteristics of the antenna having the structure shown in FIGS. 6(a) and 6(b). As is clear from FIG. 7(a), there is resonance at two frequencies. Also, the seventh
Figure 6 shows an example of the radiation characteristics of the antenna having the structure shown in Figures 6(a) and 6(b). If A is 715MHz, B is 910MHz
This is the case.

Although the case of a rectangular microstrip antenna has been described above, other shapes such as a circular shape can be similarly configured. FIG. 8 shows an embodiment using a circular microstrip antenna.

4- Here, (a) is a plan view, and (b) is a sectional view. Semicircular elements with different radii R1+R2 are provided on one side and the other side of the through hole row or pin row as boundaries. Each element resonates at a resonant frequency given by the following equation.

As explained above, according to the present invention, by arranging radiating elements with different resonance frequencies via a through-hole array or a pin array using an image effect, it is possible to achieve dual frequency sharing with a small and simple configuration. This simplifies the configuration of an array antenna in which a large number of elements are arranged, and has the advantage of reducing costs.

[Brief explanation of the drawings] Figure 1 is a cross-sectional view showing an example of conventional dual frequency band sharing, and Figures 2 (a) and (b)' are cross-sectional views of other conventional dual frequency band sharing examples. Plan view and cross-sectional view showing an example, Figure 3 (a) Φ
) Planar and cross-sectional views showing the electric field distribution of the fundamental mode of the upper microstrip antenna, Figure 4 (a) (b)
5(a) and 5(b) are a plan view and a sectional view showing an example of an antenna simplified using an image effect, FIG. a) and (b) are a plan view and a sectional view showing another embodiment of the present invention, and FIG.
a) Φ) is the V of the antenna with the structure shown in Fig. 6(a)(g))
SWR characteristic example Characteristic example Radiation directivity characteristic side view, Figure 8 (a) (
b) is a plan view and a sectional view showing another embodiment of the present invention. 1...Radiating element for reception, 2...Radiating element for transmission, 3
...Dielectric plate, 4...Metal board, 5...Power supply pin, 6...Metal plate, 7...Connector, 8...Earth pin (through hole), 9...1/ 4 wavelength transformer. Patent Applicant Nippon Telegraph and Telephone Public Corporation Agent Tsuneo Shiramizu and 1 other person 7- Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 10 / Fig. 6, Fig. 7 Frequency (MHz: 1 Angle (dead))

Claims (3)

[Claims] (1) It has a dielectric plate, a metal substrate placed on one side of the dielectric plate, and a through hole row or pin row connecting both sides of the dielectric plate via the dielectric plate, and A microstrip antenna for dual frequency bands, characterized in that a metal plate having a shape such as a square or a circle is arranged with one side of the boundary and the other side having different sizes, with the through-hole row or the pin row as a boundary. (2) The two frequencies according to claim 1, wherein the metal plate has a rectangular shape and is divided by the through-hole row or the pin row so that the areas thereof are different from each other. Band-sharing microstrip antenna. (3) The shape of the metal plate is two semicircles with different radii 1
2. The microstrip antenna for dual frequency bands according to claim 1, characterized in that the microstrip antenna has a shape of - and is in contact with the through-hole row or pin row as a boundary.