JPS62173803A - Antenna - Google Patents

Abstract

PURPOSE:To obtain a system superior in impedance characteristic by using a dielectric substrate having a part, where conductor films on both faces overlap, as a radiation element and making the resonance of an antenna possible even if the gap between an enclosure and the radiation element is narrowed. CONSTITUTION:An earth conductor 3 and a feeding conductor 4 are connected between an enclosure 1 having parts, which supply a radiation power, and a radiation element 12 near the enclosure 1. Since there is the part where conductor films 7 and 8 on both faces of the dielectric substrate constituting the radiation element 12 overlap, an equivalent capacitance is obtained, and the input impedance in an approximate short-circuit state is improved when the gap between the dielectric substrate 6 and the enclosure 1 is narrowed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a small antenna device with excellent impedance characteristics.

[Conventional technology]

These four conventional antenna devices are shown in FIG.

Figure 3 (bl is a front view, Figure 3 (a) is a plan view,
FIG. 3(0) is a side view.

tl+ is a casing that contains parts that supply radiated power, (2)
(3) is a grounding conductor for grounding this housing and the radiating element; (4) is the radiation conductor between this housing and the radiating element. A power supply conductor (5
) is a dielectric material that completely insulates this housing and the power supply conductor. Since this antenna device is configured as described above, the power fed through the power feeding conductor (4) is transmitted to the upper body f.
Radio waves are excited between i+ and the radiation conductor 21.

This radio wave bends around the edge of the radiation conductor (2) and is radiated into space. If the size of the radiation conductor (21) is small compared to the wavelength, the grounding conductor (3) serves to significantly lower the overall resonant frequency of this antenna device.

[Problem that the invention seeks to solve]

In the conventional antenna device as described above, when the distance between the housing tl+ and the radiation body (2) is narrowed, the feeding conductor (41
The input impedance seen from the power supply point becomes worse, approaching a short-circuit condition. Therefore, when trying to form a groove antenna that is sufficiently small compared to the wavelength, there is a problem in that the effect of using only the grounding conductor (31) is small and it is difficult to achieve resonance.

This invention was made to solve the above-mentioned problems, and aims to provide an antenna device that resonates even when the distance between the casing fi+ and the conductor plate (21) is sufficiently narrowed.

[Means for solving problems]

The antenna device according to the present invention uses, as a radiating element, a dielectric substrate having conductive films on both sides and a portion where the two conductive films overlap with a dielectric interposed therebetween. Also,
A dielectric substrate having two separate conductive films and a lumped constant circuit element connected therebetween is used as a radiating element.

[Effect]

In this invention, since a dielectric substrate having a portion where conductor films on both sides overlap is used as a radiating element, the overlapped portion has an equivalent capacitance, which improves the input impedance close to a short circuit state. Bring the antenna to full resonance.

In another aspect of the present invention, a lumped constant circuit element is added to improve the input impedance close to a short-circuit condition and bring the antenna into a resonant condition.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention.
l is a plan view, fbl is a front view, and 10) is a side view.

(2), +31, +41, and (5) are the same as in the conventional device described above. (6) is a dielectric substrate provided close to the casing Il+; (6) and conductor film 17+
, l).

In the antenna device configured as described above, the conductive films (7) and (8) present on both sides of the dielectric substrate (6) have exposed portions, so they have equivalent capacitance, and the dielectric It is possible to improve the input impedance, which is close to a short circuit state when the distance between the substrate (6) and the housing +11 is narrowed.

FIG. 2 is a block diagram showing another embodiment of the invention. Figure 2 fbl is a front view, Figure 2 (8L1 is Senmen Haya Figure 2) (
0) is a side view.

H1 and +31-(6) are the same as in the embodiment of FIG. +91 and +101 are conductive films etched on the surface of the dielectric substrate (6), (lla) and (llb)
, -=-(IR) is a lumped constant circuit element connected to the conductor film (9) and (101), which may be a capacitor or a coil.

With the above configuration, by appropriately determining the lumped constant circuit elements, it is possible to improve the input impedance near a short circuit state.

〔Effect of the invention〕

As described above, this invention uses a dielectric substrate with a conductive film etched on its surface as a radiating element provided close to the casing, thereby narrowing the distance between the casing and the radiating element. The antenna can be made to resonate even when the antenna is moved, and a small antenna device with excellent impedance characteristics can be realized.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the invention, FIG. 2 is a diagram showing another embodiment of the invention, and FIG. 3 is a diagram showing a conventional antenna device. In the figure, (1) is the housing, (2) is the radiation conductor, and (3) is the grounding conductor. (4) is a power supply conductor, (5) is a dielectric, and (6) is a dielectric substrate. (7), (8), (9), QG is a conductive film,
(lla), (Hb), =..., (
Itz) is a lumped constant circuit element, and (6) is a radiating element. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] It is composed of a casing for which parts supply radiated power, a radiating element provided in close proximity to the casing, and a grounding conductor and a power supply conductor connecting between the casing and the radiating element. An antenna device characterized in that the radiating element has a conductive film on one or both sides of a dielectric substrate and has a circuit element.