JPS639135Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a microstrip antenna particularly suitable for use in portable radio equipment and the like.

Traditionally, mobile radios and other devices that serve as mobile stations have used elongated linear antennas such as whip antennas and rod antennas, but these antennas are prone to breakage because they are used in a state that protrudes from the portable radio. Accidents were frequent.
In addition, the antenna had to be extended and attached each time the radio was used, which caused problems in its operability.

Therefore, it is conceivable to use a microstrip antenna that is formed into a flat plate shape and has a low profile.

Figure 1a shows an example of such a microstrip antenna in an overhead view, and Figure 1b shows an example of such a microstrip antenna.
is a sectional view taken along line X-X' in FIG. 1a.

In this figure, 1 is a radiating element that transmits (receives) electromagnetic waves, 2 is a dielectric, and 3 is a ground conductor.

4 is a feeding point of the radiating element 1, and 5 is an input/output terminal for connecting a coaxial cable, a feeder, or the like.

In a microstrip antenna with such a structure, the radiating element 1 has a rectangular shape with sides a and b, and if the dielectric constant of the dielectric 2 is εr, approximately b≒λ/21/√εr. It resonates at the wavelength λ of the formula shown.

Usually a is smaller than 2b and is chosen to have a width of approximately half a wavelength. Furthermore, the input impedance of the antenna changes depending on the position of the feeding point 4.

The directivity of this antenna becomes a directivity pattern as shown in FIG.

That is, if the direction perpendicular to the plane of the paper is the z-axis with respect to the x and y axes in Fig.・The directivity in the z-plane is relatively sharp.

By the way, in general, when using an antenna between fixed stations, the sharper the antenna's directivity, the better. However, as mentioned above, when using a microphone strip antenna as a communication antenna for mobile stations such as portable radios, In this case, the position of the moving object constantly changes due to vibrations and oscillations, so it is desirable that the directivity be wide-angle.

This idea was made in view of the actual situation, and was devised so that the directivity of the microstrip antenna would be wide-angle.

The microstrip antenna of this invention will now be described.

Figures 3a and 3b show an embodiment of this invention. Figure 3a is an overhead view of the microstrip antenna, and Figure 3b is a view taken from the Y-Y' line in Figure 3a. In the cross-sectional view, numeral 11 is a rectangular radiating element, 12 is a dielectric material, and 13 is a rectangular radiating element.
is a ground conductor, 14 is a feeding point of the radiating element 11, and 15 is an input/output terminal to which a coaxial cable, feeder, etc. for inputting/outputting excitation power or received power is connected.

As is clear from a comparison between FIG. 3b and FIG. 1b, the microstrip antenna of this invention is bent by an angle α in a plane including the feeding point 14.

When the radiating element 11 is bent at an acute angle in this way, the electromagnetic waves transmitted and received by the radiating element 11 will have various modes compared to the flat radiating element 1 shown in FIG. The characteristics can also be broad.

Figure 4 shows the directivity for electromagnetic waves of approximately 950 MHz when the bending angle α of the microstrip antenna shown in Figures 3a and b is approximately 90°, and compared to that in Figure 2. In particular, it can be seen that the orientation angle of the magnetic field H plane (y/z plane) is expanding.

Therefore, when a microstrip antenna with such directional characteristics is used in a portable radio device that moves frequently, it is possible to transmit (receive) a constant electromagnetic wave even when the moving object is shaken. become.

Note that the bending direction needs to be such that the radiating element 11 is on the outer surface of the antenna, that is, it needs to be bent at an acute angle.

Figures 5a and 5b show other embodiments of this invention; Figure 5a is a diagram bent approximately 90 degrees at two bending lines m and n; teeth,
This is an example of bending along three bending lines m, n, and l.

Although the directional characteristics are not particularly shown in the drawings due to such bending, it goes without saying that the directional characteristics become broader compared to the flat microstrip antenna shown in Figure 1 a and b. do not have.

FIG. 6 shows a schematic diagram of the case where the microstrip antenna A shown in FIG. 5a is arranged in a housing C of a portable transmitter/receiver, for example, a transceiver.

The housing C of a transceiver, etc. is miniaturized to make it convenient to carry, and is usually operated by being held in the left hand H as shown in the figure. Since the microstrip antenna A is formed to match the shape of the casing C, it is not exposed to the outside unlike a rod antenna or a whip antenna, and there is no chance of the antenna breaking. Also, since the left hand H side can be the ground conductor side of the microstrip antenna A,
The left hand H grasping the housing C does not interfere with the antenna.

Note that the radiating element 11 is not limited to a rectangular shape, but can also be circular.

As explained above, the microstrip antenna of this invention can broaden the directivity characteristics of the microstrip antenna by simply bending it at a certain angle around the feeding point of the radiating element. It is useful as a transmitting (receiving) antenna in
It also has the advantage of being easy to arrange within the housing of the transmitter.

[Brief explanation of the drawing]

Figures 1a and b are an overhead view of the microstrip antenna and a sectional view taken along line X-X', Figure 2 is a directional characteristic diagram of the microstrip antenna in Figure 1, and Figure 3a is a , b are overhead views of a microstrip antenna showing an embodiment of this invention, and Y-
A cross-sectional view taken from the Y' line, Figure 4 is a directional characteristic diagram of the microstrip antenna in Figure 3, Figure 5 a,
Fig. 6b is a perspective view showing another embodiment of the microstrip antenna of this invention, and Fig. 6 is a schematic diagram of the microstrip antenna arranged in a portable radio case. In the figure, 11 is a radiating element, 12 is a dielectric, 13 is a ground conductor, 14 is a power supply point, and 15 is an input/output terminal.

Claims (1)

[Scope of utility model registration request] A microstrip antenna comprising a radiating element and a ground conductor sandwiching a dielectric, characterized in that the entire microstrip antenna is bent so that the surface of the radiating element forms an acute angle. Lip antenna.