JP2003283236A - Dielectric antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric antenna capable of stabilizing electric characteristics by preventing influences from surrounding metallic parts and electronic components. <P>SOLUTION: The antenna comprises a plate-like dielectric substrate 1 composed of a dielectric ceramic material and a shielded electrode 9 on the side surface of the substrate 1, so that the antenna is resistant to be influenced by the outside of the radiating electrode, i.e., the metallic parts and electronic components. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric antenna used for portable terminals and wireless communication. 2. Description of the Related Art An example of this type of dielectric antenna is disclosed in Japanese Patent Laid-Open Publication No. Hei 10-98322, in which a radiating electrode forming an antenna element is provided on one main surface of a flat dielectric substrate. A ground electrode is provided on the entire surface of the other main surface, the radiation electrode is formed smaller than the ground electrode, and a coaxial feed line extends from one main surface of the flat dielectric substrate to the other main surface. A center conductor is provided, and an outer conductor of the coaxial feeder is connected to a ground electrode. [0003] Also, Japanese Patent No. 2833802 discloses that
In a microstrip antenna in which a radiating conductor is provided on one main surface of a flat dielectric substrate at substantially the center of one main surface and a first ground conductor is provided on the entire other main surface, the radiating conductor and the first A second ground conductor is provided on an outer peripheral portion of the planar dielectric substrate to reduce an electric field between the first and second ground conductors to reduce an interval between the radiating conductor and the first ground conductor. It is disclosed that the freezing electric field formed in the air between the end and the ground conductor can be reduced. [0004] This type of dielectric antenna is generally used by being incorporated in a portable terminal or a wireless communication device. On the other hand, mobile terminals and wireless communication devices are becoming smaller and lighter from the viewpoint of ease of use. With the miniaturization of equipment, dielectric antennas need to be mounted in a limited space, so miniaturization is required.However, even if the miniaturization is performed, electronic circuit elements mounted on printed circuit boards and It will be mounted adjacent to the metal parts. For this reason, there is a problem that the electrical characteristics of the dielectric antenna become unstable due to the influence of the surrounding metal parts and electronic circuit elements. In order to solve this problem, it is conceivable to provide a shield member around the dielectric antenna. However, providing such a shield member is costly due to a limited mounting space and an increased number of components. It is not preferable from the viewpoint of miniaturization of equipment. Accordingly, an object of the present invention is to provide a dielectric antenna capable of stabilizing electrical characteristics by preventing the influence of surrounding metal parts and electronic parts. In order to achieve the above object, a dielectric antenna according to the present invention has a peripheral portion of one main surface left on one main surface of a planar dielectric substrate. A radiation electrode is provided, a ground electrode is provided on the entire surface of the other main surface, a power supply electrode is provided from one main surface of the planar dielectric substrate through the other main surface, and a power supply point of the power supply electrode is connected to the radiation electrode. And a shield provided on a side surface of the flat dielectric substrate, and the shield electrode is connected to the ground electrode. By providing the shield connected to the ground electrode on the side surface of the flat dielectric substrate as described above, a shielding function can be obtained, and the radiation electrode can be hardly affected by external components, that is, electronic components or metal components. An embodiment of the present invention will be described below with reference to the accompanying drawings. 1 to 4 show a dielectric antenna according to an embodiment of the present invention. The illustrated dielectric antenna has a planar dielectric substrate 1 made of a dielectric ceramic material. The dielectric substrate 1 has a square shape in the illustrated embodiment, and has one main surface 2 and the other main surface 3. Provided and its corner 4 is chamfered as shown. The chamfered corner 4 has a function of recognizing the direction of the antenna. A radiation electrode 5 is provided on one main surface 2 of the dielectric substrate 1 except for a peripheral portion 2a of the one main surface 2. The radiation electrode 5 is formed by using an appropriate film forming technique, and has a corner 5a corresponding to the chamfered corner 4 of the dielectric substrate 1 and a corner 5b diagonally opposite to the corner 5a. It is formed so as to be obliquely chipped. As shown in FIG. 2, a ground electrode 6 is formed on the entire surface of the other main surface 3 of the dielectric substrate 1. A power supply electrode 7 is provided at a position deviated from the center position of the planar dielectric substrate 1 so as to penetrate from the one main surface 2 of the planar dielectric substrate 1 to the other main surface 3. The feeding point 7 a of 7 is electrically connected to the radiation electrode 5. The power supply electrode 7 is electrically insulated from the ground electrode 6 on the other main surface 3 as indicated by reference numeral 8 in FIG. Further, shield electrodes 9 are independently provided on each of the four side surfaces of the flat dielectric substrate 1. One end 9a of each shield electrode 9 is connected to the ground electrode 6,
The other three ends are separated from the edge of the planar dielectric substrate 1 as shown in FIG. The specific dimensions of each part of the illustrated dielectric antenna configured as described above will be exemplified. Material of dielectric substrate 1: relative permittivity 21 Size of dielectric substrate 1: length 23.6 mm, width 23.6
mm, height 4.0 mm Size of radiation electrode 5: length 19.4 mm, width 19.8 m
m Size of ground electrode 6: length 23.6 mm, width 23.
6 mm Size of power supply electrode 7: length 7.8 mm, diameter 0.8 mm Size of shield electrode 9: length 3.0 mm, width 2.0 m
m In the illustrated embodiment, the antenna is formed in a rectangular shape, but may be formed in another polygon or a circle instead. Further, the shield electrodes 9 are formed independently on the four side surfaces of the planar dielectric substrate 1, but they must be formed continuously on the four side surfaces of the planar dielectric substrate 1 as shown in FIG. You can also. As described above, in the dielectric antenna according to the present invention, the radiation electrode is provided on one main surface of the planar dielectric substrate while leaving the periphery of the one main surface. A ground electrode is provided on the entire surface of the other main surface, a power supply electrode is provided from one main surface of the planar dielectric substrate to penetrate the other main surface, and a power supply point of the power supply electrode is connected to the radiation electrode. Since the shield is provided on the side of the dielectric substrate and the shield electrode is connected to the ground electrode, the antenna itself can have a shield function, eliminating the need to separately install a shield member in the device to which the antenna is mounted. It is advantageous in terms of space and cost,
It is hard to be affected by electronic components and metal components arranged in the periphery, and the influence on the electrical characteristics of the antenna can be reduced, and the electrical characteristics can be stabilized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view showing one embodiment of a dielectric antenna according to the present invention. FIG. 2 is a schematic bottom view of the dielectric antenna of FIG. FIG. 3 is a schematic side view of the dielectric antenna of FIG. 1; FIG. 4 is a schematic sectional view along an arrow AA in FIG. 1; FIG. 5 is a schematic side view showing a modification of the dielectric antenna of FIG. 1; [Description of Signs] 1: Flat dielectric substrate 2: Dielectric substrate 1 One main surface 2 a: Peripheral portion 3 of one main surface 2: Dielectric substrate 1 The other main surface 4: Corner 5: Radiation Electrode 5a: corner 5b of radiation electrode 5: corner 6 of radiation electrode 5: ground electrode 7: power supply electrode 7a: power supply point 9 of power supply electrode 7: shield electrode

Claims (1)

Claims: 1. A flat plate-like dielectric substrate having a radiation electrode provided on one main surface thereof, leaving a peripheral portion of the one main surface, and a ground electrode provided on the entire surface of the other main surface. A power supply electrode is provided from one main surface of the dielectric substrate through the other main surface,
A dielectric antenna comprising: a feed point of a feed electrode connected to a radiation electrode; a shield provided on a side surface of a flat dielectric substrate; and a shield electrode connected to a ground electrode.