JPS6036642B2 - antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna that is small, lightweight, and has excellent characteristics that is suitable for mobile bodies and portable wireless devices.

FIG. 1 shows a cross-sectional view of a conventionally used circular slot antenna. In FIG. 1, reference numeral 1 indicates a circular conductor thin plate, and 2 a conductor substrate having a circular cavity, which forms a cavity resonator and a circular slot with the conductor thin plate 1. When high-frequency power is supplied from an excitation source (not shown) to the center of the thin conductor plate 1 via the connector 3 and the conductor bar 4, resonance occurs with the diameter of the conductor plate 1 being approximately half the wavelength, and the edge of the thin conductor plate 1 exhibits resonance. In the slot between the conductive substrate 2 and the conductive substrate 2, an electric field is generated as shown by the arrow in the figure, and is reflected upward to the left and right within the vertical plane of the antenna, as shown by characteristic a in FIG. but,
In some applications, it may be important to shoot the neck upward or in one direction, either to the left or right, and this may not be suitable for the purpose of use.

In order to deal with this problem, the present invention makes the slot formed by the thin conductive plate and the conductive substrate into an asymmetrical shape, although it is roughly circular, by installing the thin conductive plate eccentrically or by other means, thereby improving the directivity in the vertical plane. It is used to create a desired pattern. FIG. 3 is a sectional view showing a first embodiment of the present invention.

This antenna is constructed by making the center of the thin conductive plate 6 eccentric to the center of the cavity of the conductive substrate 5.

In this way, slot 7 is set wider than slot 8, so mirroring is more likely to occur than slot 8, but
Since the slot 8 is narrow, the electric field is concentrated in this portion, and the electric field intensity radiated from the neck is weaker than that on the slot 7 side.

Therefore, the Korean shot in the wide part of the slot is stronger than the narrow part, and the zero line of the neck shot moves toward the narrow direction of the slot, as shown by the dotted line b in Figure 3, and the neck shot pattern also becomes as shown by characteristic c. It becomes asymmetrical and has an upward cervix component, making it possible to form a cervix that is close to the desired pattern.

Figure 4 shows the voltage standing wave distribution v when the radial resonant disk is scale centered, and the distribution v when there is no scale center.
Compared to 2, an equivalent capacitance 9 is formed due to the electric field concentration effect in the narrow part of the slot, which has the effect of making the wavelength longer and therefore the resonant frequency slightly lower, and the potential distribution at the end of the resonant disk becomes asymmetric. I understand. FIG. 5 is a plan view of a second embodiment of the invention.

In the example shown in FIG. 3, the resonant disk is eccentric, but in this embodiment, a protrusion 11 and a recess 12 are formed in the conductive substrate 10 to achieve the same effect. Further, 13 is a slit formed in the conductor thin plate 14, which is provided when it is necessary to suppress the generation of other higher-order resonance modes, as is well known.

As is clear from the above description, the present invention allows the slot formed by the conductive substrate and the thin conductive plate to be formed into a roughly circular ring shape, while making the slot wider in the direction in which the directivity characteristics are desired to be biased. By making it asymmetrical, it is possible to obtain a desired radiation pattern with directivity in the vertical direction, and it relates to antennas that will be used in future mobile communications and portable radios using microwaves and millimeter waves.

In addition to reducing interference by reducing unnecessary Korean radiation such as in the direction of the ground, it is possible to improve the gain by that amount.It also has the effect of eliminating insensitive radiation areas in the necessary directions, and the structure is It can be easily used as an antenna suitable for mobile communication.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional circular slot antenna, Figure 2 is a diagram showing its directional characteristics, Figure 3 is a cross-sectional view of an embodiment of the present invention, and Figure 4 is a diagram showing its standing wave voltage distribution. The figure shown in FIG. 5 is a plan view showing another embodiment of the present invention. 5... Conductor substrate, 6... Conductor thin plate, 7, 8
・・・・・・Slot. Figure l Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) a conductive substrate in which a generally circular cavity is formed; a generally circular conductive thin plate installed in the cavity so as to form a generally circular ring-shaped slot between the conductive substrate; An antenna comprising a high-frequency excitation wave excited at a specific point of the thin conductive plate, and wherein the slot formed by the conductive substrate and the thin conductive plate is asymmetrical.