JPH1032421A - Surface mounted antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna capable of easily attaching a power feeding terminal, exciting a radiation electrode without contacting through capacity and easily performing matching. SOLUTION: In this antenna 10, a ground electrode 2 is formed on one main surface of a base body in a rectangular parallellopiped shape and the radiation electrode 3 in a strip shape is formed on the other main surface. In this case, one end of the radiation electrode 3 forms an open end, the other end is connected to the ground electrode 2, one end of a power feeding electrode 4 is provided through a gap 4 near the open end of the radiation electrode 3, the other end of the power feeding electrode 4 is formed through the gap 6 with the ground electrode 2 and the gap 6 is made larger than the gap 5. In such a manner, coupled capacitance is easily adjusted by coupling by the gap 6, input is easily matched by making stray capacitance between the power feeding electrode 4 and the ground electrode 2 small and a specific band width is taken wide as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount antenna used for mobile communication equipment and the like.

[0002]

2. Description of the Related Art λ /
FIG. 6 shows a type 4 patch antenna. 6, a patch antenna 60 has a ground electrode 62 formed on one main surface of a plate-shaped base 61 made of a dielectric, and a radiation electrode 63 formed on the other main surface. The radiation electrode 63 is connected to the ground electrode 62 on one main surface of the base 61 by a plurality of short pins 64 on one side thereof. A power supply pin 65 is provided near the center of the radiation electrode 63.

[0003] The patch antenna 60 configured as described above.
When a high-frequency signal is input from the power supply pin 65 to the radiation electrode 63, the radiation electrode 63 resonates as a resonator having a length λ / 4 having the short pin 64 side as a ground end and the opposite side as an open end, A part of the electric power is radiated to the space and functions as an antenna. In addition, impedance matching is performed by installing the power supply pin 65 at an appropriate position between the ground end and the open end.

[0004]

However, the above-described patch antenna 60 has a problem in that the feed pin 65 is difficult to be attached because the feed pin 65 is located near the center of the radiation electrode 63, and a through hole is required. Was. When the size of the patch antenna 60 is reduced,
Since the 5 approaches the short pin 64, there is a problem that matching becomes difficult to obtain due to the inductance of the power supply pin 65, and the resonance frequency varies.

Therefore, the present invention can provide non-contact excitation via a capacitor and can easily achieve matching even when the size is reduced.
An object of the present invention is to provide an antenna having a structure that is easily mounted on a surface because an input end is located at an end of a base.

[0006]

In order to solve the above-mentioned problems, a surface mount antenna according to the present invention has a ground electrode formed on one main surface of a rectangular parallelepiped base made of a dielectric or a magnetic material. A strip-shaped radiation electrode is formed on at least the other main surface of the base, one end of the radiation electrode forms an open end on the other main surface or any end surface of the base, and the other end is connected to the ground electrode, A surface-mounted antenna in which one end of a power supply electrode is formed through a gap at an open end of the radiation electrode, wherein the power supply electrode has the other end facing the ground electrode, One end of the power supply electrode and the open end of the radiation electrode are formed continuously from the surface on which the open end is formed to one main surface of the base, and the gap between the other end of the power supply electrode and the ground electrode is formed. Characterized by being larger than the gap between.

In the surface mount antenna according to the present invention, a ground electrode is formed on one main surface of a rectangular parallelepiped base made of a dielectric or magnetic material, and a strip-shaped radiation electrode is formed on at least the other main surface of the base. One end of the radiation electrode forms an open end on the other main surface or any end surface of the base, the other end is connected to the ground electrode, and the power supply electrode is connected to the open end of the radiation electrode via a gap. A surface-mounting antenna having one end formed thereon, wherein the power supply electrode is arranged such that the other end thereof faces the ground electrode, and one main surface of the base is formed from a surface of the base on which an open end of the radiation electrode is formed. And the width of the power supply electrode on one main surface of the base is made narrower than that of one end side, and the length is approximated to the width.

In the surface-mounted antenna according to the present invention, a ground electrode is formed on one main surface of a rectangular parallelepiped base made of a dielectric or magnetic material, and a strip-shaped radiation electrode is formed on at least the other main surface of the base. One end of the radiation electrode forms an open end on the other main surface or any end surface of the base, the other end is connected to the ground electrode, and the power supply electrode is connected to the open end of the radiation electrode via a gap. Wherein the power supply electrode is formed continuously from the surface on which the open end of the radiation electrode is formed to one main surface of the base, and on one main surface of the base, A groove is provided between a power supply electrode and the ground electrode.

With this configuration, according to the surface mount antenna of the present invention, non-contact excitation can be performed, and the coupling capacitance can be easily adjusted and matching can be easily achieved. Further, even if the relative dielectric constant of the base is large, the stray capacitance between the power supply electrode and the ground electrode can be reduced,
The input can be easily matched, and the relative bandwidth can be widened.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a surface mount antenna according to the present invention will be described below with reference to the drawings. In FIG. 1, a surface-mounted antenna 10 includes a rectangular parallelepiped base 1 made of a dielectric material such as ceramics and resin, a ground electrode 2 formed on the surface of the base 1, and a strip-shaped length λ /
It is composed of a radiation electrode 3 and a feed electrode 4 that are approximately four in size. The ground electrode 2 is formed on one main surface of the base 1,
The radiation electrode 3 is formed on the other main surface of the base 1. Further, one end of the radiation electrode 3 goes around one end surface of the base 1 to form an open end, and the other end is formed continuously on the opposite end surface of the base 1 and is connected to the ground electrode 2. The power supply electrode 4 has one end formed on the one end surface of the base 1 near the open end of the radiation electrode 3 and the radiation electrode 3 via the gap 5.
The other end goes around one main surface of the base 1 to form the ground electrode 2
And a gap 6. The gap 6 between the power supply electrode 4 and the ground electrode 2 is set larger than the gap 5 between the power supply electrode 4 and the radiation electrode 3. The high-frequency signal source 7 is connected to the power supply electrode 4.

FIG. 2 shows an electrical equivalent circuit of this embodiment.
In FIG. 2, an equivalent circuit 20 of the surface mount antenna 10 is shown.
Are the inductor 11 that is the self-inductance of the radiation electrode 3, the resistor 12 that is the radiation resistance, the capacitor 13 that is the capacitance formed between the open end of the radiation electrode 3 and the ground electrode 2, and the open end of the radiation electrode 3. A capacitor 14 which is a capacitance formed between the power supply electrode 4 and a capacitor 15 which is a capacitance formed between the power supply electrode 4 and the ground electrode 2
It consists of. Among them, the inductor 11, the resistor 12, and the capacitor 13 are connected in parallel, and one end thereof is grounded. The other end is grounded via capacitors 14 and 15 in series. A high-frequency signal source 16 is connected to a connection between the capacitors 14 and 15.

Next, the operation of the surface mount antenna 10 will be described with reference to the equivalent circuit shown in FIG. Surface mount antenna 1
The zero resonance circuit mainly includes an inductor 11, a resistor 12, and a capacitor 13.

When a signal is input from the high frequency signal source 16 to the resonance circuit via the capacitor 14, the energy of the input signal resonates in the resonance circuit, and a part of the energy is radiated into the air to function as an antenna. . This emitted energy is represented as energy consumed by the resistor 12 in an equivalent circuit.

The capacitor 14 has a function as an inlet for supplying energy to the resonance circuit, and at the same time,
It also has a function of matching with an external circuit together with the capacitor 15. Here, by making the gap 6 between the power supply electrode 4 and the ground electrode 2 larger than the gap 5 between the power supply electrode 4 and the radiation electrode 3,
Is small, and the capacitance of the capacitor 15 is sufficiently smaller than the capacitance of the capacitor 14 as an equivalent circuit.

The inventor of the present application has disclosed a surface mount antenna according to the present embodiment, in which a gap 6 between a feed electrode 4 and a ground electrode 2 is provided.
An experiment was performed to measure the change in antenna characteristics (fractional bandwidth, reflection loss) when was changed. In this experiment, the gap 5 was 0.7 mm. The result is shown in FIG. 3, the horizontal axis indicates the distance of the gap 6, A indicates the specific bandwidth, and B indicates the return loss. Generally, the return loss of an antenna for a portable device is-
Although 9.5 dB or less is required, it is apparent from this graph that the reflection loss is -9.5 dB or less when the distance of the gap 6 is 1.4 mm or more. Also, the fractional bandwidth increases as the distance of the gap 6 increases, which contributes to the improvement of antenna characteristics together with the reflection loss.

FIG. 4 shows another embodiment of the surface mount antenna according to the present invention. Referring to FIG.
The width of the power supply electrode 4a formed on the one main surface side of the base 1 is smaller than the width of the power supply electrode 4a formed on the radiation electrode 3 via the gap 5, and the length is approximated to the width. , And the ground electrode 2a and the gap 6a. The other configuration is the same as that of the embodiment of FIG. 1, and the equivalent circuit is the same as that of FIG. 2. The same parts are denoted by the same reference numerals, and the description of the equivalent circuit and operation is omitted. In the present embodiment, the width of the power supply electrode 4a on one main surface side of the base 1 is made smaller than the width of the end surface side of the base 1, thereby forming the gap 6a between the power supply electrode 4a and the ground electrode 2a. The distance becomes longer, thereby reducing the stray capacitance. Even in an equivalent circuit, the capacitance of the capacitor 15 is sufficiently smaller than the capacitance of the capacitor 14.

FIG. 5 shows still another embodiment of the surface mount antenna according to the present invention. In FIG. 5, a groove 8 is formed in one main surface of the base 1 between a portion of the feed electrode 4 of the surface-mounted antenna 50 wrapping around the one main surface of the base 1 and the ground electrode 2 b. I have. Other configurations are the same as those of the embodiment of FIG. 1, and the equivalent circuit is the same as that of FIG.
The same parts are denoted by the same reference numerals, and the description of the equivalent circuit and operation is omitted. In this embodiment, by providing the groove 8 between the power supply electrode 4 and the ground electrode 2b on one main surface of the base 1, the stray capacitance between the power supply electrode 4 and the ground electrode 2b is reduced, and an equivalent circuit is formed. Also, the capacity of the capacitor 15 is sufficiently smaller than the capacity of the capacitor 14. This effect is particularly remarkable when the relative dielectric constant of the base 1 is large.

In each of the above embodiments, a linear radiation electrode is employed. However, even if the radiation electrode is formed in another shape such as an L shape, a U shape, a meander shape, the same operation and effect can be obtained. Can be obtained. Further, the dielectric is used as the base, but the base may be formed of a magnetic material.

[0019]

According to the surface mount antenna of the present invention,
By providing a gap between the open end of the radiation electrode and the feed electrode, non-contact excitation can be achieved by capacitive coupling, and matching can be easily achieved by adjusting the gap.

Further, the gap between the power supply electrode and the ground electrode is formed to be larger than the gap between the power supply electrode and the radiation electrode, or the width of one main surface side of the power supply electrode is opposed to the radiation electrode. The stray capacitance between the power supply electrode and the ground electrode is reduced by making it narrower than the width on the side on which it is formed and by making it a length that approximates the width, or by providing a groove between the power supply electrode and the ground electrode. The input can be easily matched, and the fractional bandwidth can be widened.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a surface mount antenna according to the present invention, in which (a) is a perspective view seen from a radiation electrode side;
(B) is the figure seen from the ground electrode side.

FIG. 2 is a circuit diagram showing an equivalent circuit of the surface mount antenna of FIG.

FIG. 3 is a diagram showing the relationship between the shortest distance of the gap between the feed electrode and the ground electrode and the antenna characteristics of the surface mount antenna of the present invention.

4A and 4B are perspective views of another embodiment of the surface mount antenna according to the present invention, in which FIG. 4A is a view from the radiation electrode side, and FIG. 4B is a view from the ground electrode side.

FIG. 5 is a perspective view of still another embodiment of the surface mount antenna according to the present invention, wherein FIG.
(B) is the figure seen from the ground electrode side.

FIG. 6 is a perspective view of a conventional surface mount antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base 2 ... Ground electrode 3 ... Radiation electrode 4 ... Feeding electrode 5, 6 ... Gap 6 ... High frequency signal source 10 ... Surface mount antenna

Claims (3)

[Claims] 1. A ground electrode is formed on one main surface of a rectangular parallelepiped base made of a dielectric or a magnetic material, and a strip-shaped radiation electrode is formed on at least the other main surface of the base. A surface mount antenna having an open end formed on the other main surface or any end surface of the base, the other end connected to the ground electrode, and one end of a feed electrode formed at the open end of the radiation electrode via a gap. Wherein the power supply electrode is formed continuously from the surface of the base on which the open end of the radiation electrode is formed to one main surface of the base such that the other end faces the ground electrode; A surface mount antenna wherein a gap between the other end of the electrode and the ground electrode is larger than a gap between one end of the feed electrode and an open end of the radiation electrode. 2. A ground electrode is formed on one main surface of a rectangular parallelepiped base made of a dielectric or a magnetic material, and a strip-shaped radiation electrode is formed on at least the other main surface of the base. A surface mount antenna having an open end formed on the other main surface or any end surface of the base, the other end connected to the ground electrode, and one end of a feed electrode formed at the open end of the radiation electrode via a gap. Wherein the power supply electrode is formed continuously from a surface of the base on which the open end of the radiation electrode is formed to one main surface of the base such that the other end faces the ground electrode; A surface-mounted antenna characterized in that the shape of the power supply electrode on one main surface is narrower than one end side and has a length approximate to the width. 3. A ground electrode is formed on one main surface of a rectangular parallelepiped base made of a dielectric or magnetic material, and a strip-shaped radiation electrode is formed on at least the other main surface of the base. A surface mount antenna having an open end formed on the other main surface or any end surface of the base, the other end connected to the ground electrode, and one end of a feed electrode formed at the open end of the radiation electrode via a gap. Wherein the power supply electrode is formed continuously from the surface on which the open end of the radiation electrode is formed to one main surface of the base, and between the power supply electrode and the ground electrode on one main surface of the base. A surface-mounted antenna characterized in that a groove is provided in the surface mount antenna.