Antenna

Abstract

An antenna which can be used in different communication standards with a simple structure is disclosed. The antenna includes an antenna section which receives/transmits radio waves, input/output ports to which a signal to be input to the antenna section is input and from which a signal output from the antenna section is output, and transmission lines each of which connects the antenna section to a corresponding input/output port.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 2 is a plan view of the antenna shown in FIG. 1;

FIG. 3 is a graph showing a VSWR (voltage standing wave ratio) of the antenna shown in FIG. 1;

FIG. 4 is a perspective view of an antenna according to a second embodiment of the present invention;

FIG. 5 is a plan view of the antenna shown in FIG. 4;

FIG. 6 is a perspective view of an antenna according to a third embodiment of the present invention;

FIG. 7 is a plan view of the antenna shown in FIG. 6;

FIG. 8 is a graph showing a frequency characteristic of a filter circuit shown in FIG. 6;

FIG. 9 is a perspective view of an antenna according to a fourth embodiment of the present invention;

FIG. 10 is a plan view of the antenna shown in FIG. 9;

FIG. 11 is a perspective view of an antenna according to a fifth embodiment of the present invention;

FIG. 12 is a plan view of the antenna shown in FIG. 11; and

FIG. 13 is a schematic diagram showing a structure of the antenna shown in FIG. 11.

Claims

1. An antenna, comprising: an antenna section which receives/transmits radio waves;input/output ports to which a signal to be input to the antenna section is input and from which a signal output from the antenna section is output; andtransmission lines each of which connects the antenna section to a corresponding input/output port.

2. The antenna as claimed in claim 1, wherein: the antenna section includes an element pattern and a ground pattern which patterns are conductive patterns formed on a dielectric material board.

3. The antenna as claimed in claim 2, wherein: the element pattern, the input/output ports, and the transmission lines are formed on one surface of the dielectric material board;the ground pattern is formed on the other surface of the dielectric material board; anda microstrip transmission line is formed of the transmission lines and the ground pattern.

4. The antenna as claimed in claim 2, wherein: the element pattern, the ground pattern, the input/output ports, and the transmission lines are formed on one surface of the dielectric material board; anda co-planar transmission line is formed of the transmission lines and the ground pattern.

5. The antenna as claimed in claim 1, wherein: a filter circuit is formed in the transmission line.

6. The antenna as claimed in claim 1, wherein: the antenna section is connected to the input/output ports via a coupler instead of the transmission lines.

7. The antenna as claimed in claim 6, wherein: the coupler is a 3 dB branch line or a power divider.

8. The antenna as claimed in claim 1, further comprising: a switching circuit which connects the antenna section to a suitable one of the transmission lines.

9. The antenna as claimed in claim 1, wherein: the antenna section is capable of communicating in at least a UWB frequency band and a wireless LAN frequency band.