JPH09260915A - Chip antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the small sized and omnidirectional chip antenna in which complexity and large scale of a matching circuit causing a limitation to miniaturization of the antenna are considerably suppressed. SOLUTION: The chip antenna 10 is formed by meandering three conductors 11a-11c made of copper or copper alloy. Then each one-end of the conductors 11a-11c is connected in common to form a feeding part 12 and the other-ends form free ends 13a-13c. In this case, the conductors 11a-11c are arranged in parallel in the loop direction of the meander line (x direction).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip antenna, and more particularly to a chip antenna applied to a small portable terminal having a small volume such as a portable mobile terminal.

[0002]

2. Description of the Related Art Conventionally, an antenna device used for a small volume terminal such as a portable mobile terminal is provided with a matching circuit in addition to the antenna body. This matching circuit is necessary in order to cancel out a large capacitance component as compared with the radiation resistance component caused by the reduction in the volume of the antenna body accompanying the further miniaturization of the terminal. An example of such an antenna device is a circular polarization antenna 50 as shown in FIG. That is, the radiation conductor 52 formed of a rectangular radiation conductor film, the 90 ° hybrid coupler 53, and the two strip lines 54 and 55 are adhered and formed on the substrate 51, and one terminal of the 90 ° hybrid coupler 53 is formed. Non-reflective terminator 56
Is attached. Further, between the output side of the 90 ° hybrid coupler 53 and the strip lines 54 and 55, the input impedance of the circular polarization antenna 50 is the characteristic impedance of the high frequency circuit adopted in the terminal.
A matching circuit 57 is inserted to match 0Ω. A ground radiation conductor film 59 is formed on the back surface of the substrate 51 by coating.

[0003]

However, in the above-described conventional antenna device, the matching circuit becomes complicated and large in size with the miniaturization of the antenna body, which becomes a factor that limits the miniaturization in terms of volume. There was a point. Further, since the ground radiation conductor film is formed on the back surface of the substrate, there is a problem that non-directionality cannot be obtained.

The present invention has been made in order to solve such a problem, and is of a small size capable of greatly suppressing the complexity and size increase of a matching circuit, which is a limitation on the size reduction of an antenna.
An object is to provide an omnidirectional chip antenna.

[0005]

In order to solve the above-mentioned problems, the present invention has a plurality of conductors parallel to each other, one end of which is a feeding portion and the other end of which is a free end, meandering in a meandering shape. The power supply units of the plurality of conductors are commonly connected, and the plurality of conductors are simultaneously and in-phase supplied with power.

Further, the plurality of conductors are formed on at least one of the surface and the inside of a substrate made of at least one of a dielectric material and a magnetic material.

According to the chip antenna of the first aspect, the plurality of conductors formed so as to be parallel to each other operate without significantly affecting each other's characteristics, and these are connected in parallel. The input impedance is close to 50Ω, which is the characteristic impedance of the high frequency circuit used in the terminal, and a better matching state with the high frequency circuit can be realized.

According to the second aspect of the chip antenna, the plurality of conductors formed so as to be parallel to each other are formed on at least one of the surface and the inside of the base made of at least one of a dielectric material and a magnetic material. Therefore, the effective line length of the conductor can be increased by the wavelength shortening action.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In each of the embodiments, the same or equivalent parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a perspective view of a first embodiment of a chip antenna according to the present invention. The chip antenna 10 includes three conductors 11a to 11c made of copper or copper alloy,
It is formed by meandering in a meandering shape. Then, one end of each of the conductors 11a to 11c is commonly connected to form the power feeding portion 12, and each of the other ends forms free ends 13a to 13c. At this time, the conductors 11a to 11
c is formed so as to be parallel to the amplitude direction of the meander (the x direction in FIG. 1).

FIG. 2 shows a perspective view of a modification of the first embodiment. Compared to the chip antenna 10 of the first embodiment, the chip antenna 20 has conductors 11a to 11c in a direction (y direction in FIG. 2) orthogonal to the amplitude direction of meander (x direction in FIG. 2). They differ in that they are formed to be parallel.

As described above, in the first embodiment and its modification, the three conductors 11a to 11c formed so as to be parallel to each other are commonly connected at one end thereof, and the power feeding unit 1 is connected.
2 is formed, the three conductors 11a to 11 having almost the same structure are formed.
The gain and the bandwidth can be improved by feeding 1c in parallel in the same phase.

Further, since the three conductors 11a to 11c meander in a meandering shape, the line length can be increased. Therefore, the bandwidth can be further widened without reducing the gain.

Further, since the ground radiation conductor film is not provided around the conductor, radio waves are not blocked by the ground radiation conductor film, and an omnidirectional chip antenna can be formed.

Further, the input impedance of the chip antennas 10 and 20 can be made close to 50Ω which is the characteristic impedance of the high frequency circuit (not shown) adopted in the terminal. Therefore, it is possible to realize a better matching state with the high frequency circuit without using a matching circuit, and it is possible to reduce the size and cost.

3 and 4 are a perspective view and an exploded perspective view of a second embodiment of the chip antenna according to the present invention.

The chip antenna 30 has a rectangular parallelepiped-shaped base 31 having a mounting surface 311 and conductors 32a to 32c meandering in a meandering shape in a direction parallel to the mounting surface 311 or in the longitudinal direction of the base 31. Become. Here, the base 31 is formed by laminating rectangular sheet layers 33a to 33c made of a dielectric material (relative dielectric constant: about 6.1) containing barium oxide, aluminum oxide, and silica as main components.

Among them, the meandering conductors 32a made of copper or copper alloy are formed on the surface of the sheet layer 33b.
32c is provided by printing, vapor deposition, laminating, or plating.

Thereafter, the sheet layers 33a to 33c are laminated and sintered to form conductors 32a to 32c, which meander in a meandering shape in the longitudinal direction of the base 31, inside the base 31.

At this time, one end of each of the conductors 32a to 32c is electrically connected to form a power feeding portion 34. Then, the power feeding section 34 is connected to a power feeding terminal 35 formed on the surface of the base 31 for applying a voltage to the conductors 32a to 32c. On the other hand, the other ends of the conductors 32a to 32c form free ends 36a to 36c inside the base 31. The conductors 32a to 32c are surfaces parallel to the amplitude direction of the meander (x direction in FIG. 3), that is, the mounting surface 31.
It is formed so as to be parallel to the surface 37 (sheet layer 33b) parallel to 1.

FIG. 5 shows a perspective view of a modification of the second embodiment. Compared to the chip antenna 30 of the second embodiment, the chip antenna 40 has a plane in which the conductors 32a to 32c formed inside the base 31 are orthogonal to the amplitude direction of the meander (x direction in FIG. 5), that is, They are different in that they are formed so as to be parallel on the surface 41 orthogonal to the mounting surface 311.

As described above, in the second embodiment and its modification, the base 31 is made of a dielectric material, so that the propagation speed becomes slow and the effective line length of the conductor is lengthened by the wavelength shortening action. You can Therefore, since the area of the current distribution is increased, the amount of radiated radio waves is increased, the antenna gain can be further improved, and the bandwidth can be further widened.

Further, since the ground radiation conductor film is not provided on the back surface of the substrate, radio waves are not blocked by the ground radiation conductor film, and an omnidirectional chip antenna can be formed.

In the first and second embodiments, the case where the meandering conductor is three has been described, but four or more meandering conductors may be formed. In that case, it is possible to further improve the gain and the bandwidth.

Also, the case where the meandering conductor has six corners has been described, but one or more may be selected according to the line length.

Further, the case where the meander shape is substantially wavy has been described, but the meander shape may be substantially rectangular shape or substantially sawtooth shape.

In the second embodiment, the case where the base of the chip antenna has a rectangular parallelepiped shape has been described, but other shapes such as a cube, a cylinder, a pyramid, a cone, and a sphere may be used.

Further, the position of the power supply terminal on the surface of the base is not an essential condition for carrying out the present invention.

Although the case where all of the conductors are provided inside the substrate has been described, all of the conductors or part of the conductors may be provided on the surface of the substrate.

Further, although the case where the meandering conductor is formed in the longitudinal direction of the substrate has been described, it may be formed in any direction as long as it is formed in a meandering form, for example, in the height direction of the substrate.

The case where the meandering conductors are provided on one sheet layer has been described, but the meandering conductors are formed by providing conductor patterns on a plurality of sheet layers and connecting the conductor patterns with via holes. You may.

[0032]

According to the chip antenna of the first aspect of the present invention, since a plurality of conductors formed to be parallel to each other are commonly connected at one end thereof to form a power feeding portion, a plurality of conductors are formed. By feeding the same phase in parallel in parallel, the gain and bandwidth can be improved.

Since the plurality of conductors meander in a meandering shape, the line length can be increased. Therefore, the bandwidth can be further widened without reducing the gain.

Furthermore, since no ground radiation conductor film is provided around the conductor, radio waves are not blocked by the ground radiation conductor film, and an omnidirectional chip antenna can be formed.

Further, the input impedance of the chip antenna can be made close to the characteristic impedance of the high frequency circuit adopted in the terminal. Therefore, it is possible to realize a better matching state with the high frequency circuit without using a matching circuit, and it is possible to reduce the size and cost.

According to the second aspect of the chip antenna, the propagation speed becomes slower and the effective line length of the conductor can be made longer by the wavelength shortening action by forming the substrate by at least one of the dielectric material and the magnetic material. it can. Therefore, since the area of the current distribution increases, the amount of radio waves emitted increases,
The antenna gain can be further improved and the bandwidth can be further widened.

Further, since the ground radiation conductor film is not provided on the back surface of the substrate, radio waves are not blocked by the ground radiation conductor film, and an omnidirectional chip antenna can be formed.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of a chip antenna according to the present invention.

FIG. 2 is a perspective view showing a modified example of the chip antenna of FIG.

FIG. 3 is a perspective view of a second embodiment of the chip antenna of the present invention.

FIG. 4 is an exploded perspective view of the chip antenna of FIG.

5 is a perspective view showing a modified example of the chip antenna of FIG.

6A is a plan view showing a conventional antenna device, and FIG. 6B is a sectional view taken along line XX in FIG.

[Explanation of symbols]

 10, 20, 30, 40 Chip antenna 31 Base body 11a to 11c, 32a to 32c Conductor 12, 33 Feeding portion 13a to 13c, 36a to 36c Free end

Claims (2)

[Claims] 1. A plurality of conductors parallel to each other, one end of which is a power feeding portion and the other end of which is a free end, meandering in a meandering shape, the power feeding portions of the plurality of conductors being commonly connected, A chip antenna characterized in that conductors are fed simultaneously and in phase. 2. The chip antenna according to claim 1, wherein the plurality of conductors are formed on at least one of a surface and an inside of a base made of at least one of a dielectric material and a magnetic material.