JPH10126134A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the degrees of freedom for the input/output impedance and the directivity and to improve the transmitting and receiving sensitivity by connecting the inner conductor formed on the inner wall of a through-hole of a columnar dielectric to a ground terminal and connecting the outer conductor prepared at the outer circumference of the dielectric to a signal terminal. SOLUTION: An inner conductor 8 and an outer conductor 10 are prepared on the inner wall of a through-hole 7 and on an outer circumference face 9 of a cylindrical dielectric 4 made of barium titanate ceramic respectively. An antenna element 1 consists of a TM-mode coaxial dielectric resonator. The terminal conductors 11, prepared on an end face 5 of the dielectric 4 and at a part of the face 9, are connected to the conductor 8 and electrically separated from the conductor 10 via a separating area 12. Then the terminals 11 are connected to a ground terminal 13, and the conductor 10 is connected to a signal input/output terminal 3 via an adjustment circuit 2. When a signal having the resonance frequency of the coaxial dielectric resonator or its approximate frequency is applied to the conductor 10, the electromagnetic waves are radiated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device suitable for mobile communication equipment.

[0002]

2. Description of the Related Art As a dielectric antenna, there has been known an antenna in which a strip line of λ / 4 or λ / 2 is provided on a dielectric substrate and resonates at a selected frequency.

[0003]

However, stripline dielectric antennas have drawbacks such as low input / output impedance and low degree of freedom in directivity, and drawbacks such as insufficient transmission / reception sensitivity.

Accordingly, an object of the present invention is to provide an antenna device capable of increasing the degree of freedom of input / output impedance and directivity and increasing the sensitivity of transmission or reception.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems and to achieve the above object, the present invention provides a columnar dielectric having a through hole extending from one end face to the other end face, and a through hole provided in the through hole. Provided, an outer conductor provided on the outer peripheral surface of the dielectric so as to surround the outer peripheral surface, a ground terminal connected to the inner conductor, and a signal terminal connected to the outer conductor. Related to the antenna device. It is desirable that the terminal conductor layer connected to the inner conductor be provided on one end face and a part of the outer peripheral face of the dielectric. Further, as described in claim 3, a conductor layer for connecting the inner conductor and the outer conductor is provided on the other end face of the dielectric, and can have the same configuration as the quarter-wavelength type dielectric resonator. .

[0006]

When the antenna device according to the present invention is used as a transmitting antenna, the resonance frequency of the resonator composed of the outer conductor, the dielectric, and the inner conductor or a transmission signal in the vicinity thereof is transmitted to the outer conductor. To supply. Thereby, a resonance operation occurs, and an electromagnetic wave is emitted. Also, when the antenna device of the present invention is used as a receiving antenna, it is excited by an electromagnetic wave radiated from the transmitting antenna, and when it resonates, a received signal having the highest output power level is obtained at a terminal connected to the outer conductor. . In this antenna device, since an outer conductor provided so as to surround the outer peripheral surface of the columnar dielectric functions as an antenna electrode, it is possible to provide an antenna with high sensitivity and wide directivity. Further, since the outer conductor is used as the antenna electrode, the connection position of the terminal with respect to the outer conductor can be easily changed, whereby the input impedance can be changed to achieve matching with the external impedance. Further, the ground conductor can be arranged so as to face the outer conductor in a specific direction, and the directivity can be easily adjusted. According to the second aspect of the present invention, the connection to the ground can be easily achieved. According to the third aspect of the present invention,
An antenna device having a different resonance frequency can be provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an antenna device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a cross section of an antenna element 1 and an adjustment circuit 2 connected thereto. The adjustment circuit 2 includes circuit elements such as an inductance L, a capacitance C, and a resistance R, and operates at an operating frequency, a bandwidth, and a V.V. S. W. R,
This is a well-known circuit that adjusts impedance and the like, and is connected to a signal input or output terminal 3. The antenna element 1 is formed in the same manner as a TEM mode coaxial dielectric resonator. A columnar or cylindrical dielectric 4 made of, for example, barium titanate-based ceramic, and one end face 5 of the dielectric 4 to the other end. The inner conductor 8 provided in the through hole 7 reaching the end face 6 and the outer conductor 1 provided on the outer peripheral surface 9 of the dielectric 4
0 and a terminal conductor 11 provided on one end face 5 and a part of the outer peripheral face 9 of the dielectric 4 and connected to the inner conductor 8. The outer conductor 10 and the terminal conductor 11 are electrically separated by a separation region 12 on the outer peripheral surface 9 of the dielectric 4.
The inner conductor 8, the outer conductor 10, and the terminal conductor 11 are formed by applying a conductive paste (silver paste) to the entire surface of the dielectric 4 and baking to form a conductor layer. It is formed by providing a separation region 12 by removing the portion in a ring shape. Therefore, the outer conductor 10 is formed so as to surround the outer peripheral surface 9 of the dielectric 4.

The terminal conductor 11 is connected to a ground terminal 13, and the outer conductor 10 is connected to a signal terminal 14. That is, the electrical connection to the inner conductor 8 and the outer conductor 10 is T
The electrical connection in the EM mode coaxial dielectric resonator is reversed.

FIG. 2 shows a specific configuration of the apparatus shown in FIG. 1. A ground terminal 13 and a signal terminal 14 made of a conductive layer are provided on a dielectric substrate 15, and a through hole 7 is formed in the substrate 15. The terminal conductor 11 and the outer conductor 10 of the antenna element 1 arranged parallel to the main surface are connected to the ground terminal 13 and the signal terminal 14 by a conductive bonding material (not shown) such as solder. The ground terminal 13 is the wiring conductor 1
6, the signal terminal 14 is connected to the adjustment circuit 2 by a wiring conductor 17. The adjustment circuit 2 is schematically illustrated by a block, but actually includes circuit elements such as L, C, and R.
A ground conductor layer 18 for directivity adjustment is provided on the lower surface of the dielectric substrate 15 below the antenna element 1. Electromagnetic waves in the direction from the antenna element 1 to the ground conductor layer 18 and in the opposite direction are cut by the ground conductor layer 18. Therefore, directivity of the antenna element 1 downward is suppressed.

When the antenna element 1 is used for transmission, when a signal having this resonance frequency or a frequency close to the resonance frequency is supplied to the antenna element 1 equivalent to an LC parallel resonance circuit, this becomes an excitation signal and the resonance occurs. An operation occurs, based on which an electromagnetic wave is emitted. Further, when the antenna element 1 is used for reception, a resonance operation occurs when receiving an electromagnetic wave having a resonance frequency of the antenna element 1 or a frequency close thereto, and a reception output is obtained at the signal terminal 14.

The antenna element of this embodiment has the following effects. (A) The coaxial dielectric resonator was not used as an antenna as it was, but instead of the dielectric resonator, the inner conductor 8 was connected to the ground terminal 13 and the outer conductor 10 was connected to the signal terminal 14. The radiation of the electromagnetic wave or the incidence of the electromagnetic wave is performed without the outer conductor 10 functioning as the inner conductor 8 being restricted by the inner conductor 8, thereby increasing the sensitivity. (B) Since the outer conductor 10 as an antenna electrode is provided so as to surround the entire outer peripheral surface of the cylindrical dielectric 4, directivity in all directions (360 degrees direction) can be obtained. (C) By arranging the antenna element 1 on the dielectric substrate 15 and providing the ground conductor layer 18 on the lower surface of the substrate 15 as shown in FIG. 2, the directivity can be easily adjusted. (D) A high gain and low loss antenna can be obtained by using the dielectric 4 as a high Q value dielectric ceramic. (E) Since the connection position of the signal terminal 14 with respect to the outer conductor 10 can be easily changed, the input impedance can be adjusted to easily match the external impedance with the external impedance. (F) The resonance frequency can be easily changed by changing the length of the dielectric 4 and the outer conductor 10. (G) Since the terminal conductor 11 is provided as an extension of the inner conductor 8, connection to the ground can be easily achieved.

[0012]

[Modifications] The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible. (1) As shown in FIG. 3, a short-circuit conductor 19 is provided on the other end face 6 of the dielectric 4 so that the same configuration as that of the quarter-wavelength dielectric resonator can be obtained. (2) Instead of the terminal conductor 11 made of a conductor layer, a metal piece or a rod terminal can be connected to the inner conductor. (3) The dielectric 4 can be formed in a prismatic shape. (4) The dielectric substrate 15 may be formed as a multilayer substrate, and the capacitor, inductance, and resistance of the adjustment circuit 2 may be embedded in the multilayer substrate.

[Brief description of the drawings]

FIG. 1 is a diagram showing in principle an antenna device of an embodiment.

FIG. 2 is a perspective view specifically showing the antenna device of the embodiment.

FIG. 3 is a cross-sectional view illustrating an antenna device according to a modification.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna element 4 Cylindrical dielectric material 8 Inner conductor 10 Outer conductor 13 Ground terminal 14 Signal terminal

Claims (3)

[Claims] 1. A columnar dielectric having a through hole extending from one end surface to the other end surface, an inner conductor provided in the through hole, and an outer peripheral surface of the dielectric body provided to surround the outer peripheral surface. An antenna device comprising: an outer conductor; a ground terminal connected to the inner conductor; and a signal terminal connected to the outer conductor. And a terminal conductor layer for connecting the ground terminal to the inner conductor, wherein the terminal conductor layer is provided on the one end face and a part of the outer peripheral face of the dielectric. The antenna device according to claim 1, wherein 3. The antenna device according to claim 1, further comprising a conductor layer that connects the inner conductor and the outer conductor to the other end surface of the dielectric.