Multi-band antenna with broadband function

Abstract

A multi-band antenna with the broadband function is based upon a planar inverted-F antenna with two conductive arms and a ground. The two conductive arms extend from the ground near the two opposite ends of the ground. Two radiation plates of the two conductive arms extend toward each other. The multi-band antenna has a sufficient large band at high frequencies. Since the conductive arms are disposed close to the two ends of the ground, operations of bending the two conductive arms or soldering a feed wires are simpler and have a higher yield.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a conventional multi-band antenna;

FIG. 2 is a perspective view showing an antenna according to a first embodiment of the invention;

FIG. 3 shows return loss of the antenna shown in FIG. 2;

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

FIG. 5 shows return loss of the antenna shown in FIG. 4.

Claims

1. A multi-band antenna comprising: a ground having a first end, a second end, a first elongated side and a second elongated side;a first conductive arm having a radiating plate and a connecting plate, the connecting plate of the first conductive arm connected to the first elongated side of the ground near the first end and extending toward the second end;a second conductive arm having a radiating plate and a connecting plate, the connecting plate of the second conductive arm connected to the second elongated side of the ground near the second end and extending toward the first end; anda coaxial feed wire having a central wire and an outer wire, the central wire electrically connected to the radiating plate of the first conductive arm, and the outer wire electrically connected to the ground;wherein the radiating plates of the first conductive arm and the second conductive arm are parallel to the ground.

2. The multi-band antenna as claimed in claim 1, wherein the positive signal wire of the feed wire is connected to the radiating plate of the first conductive arm at a connection point that divides the radiating plate into two segments with a length ratio of 1:4.

3. The multi-band antenna as claimed in claim 1, wherein the central wire of the feed wire is connected to the radiating plate of the first conductive arm at a connection point that divides the radiating plate into two segments with a length ratio between 1:1 and 1:1.5.

4. The multi-band antenna as claimed in claim 1, wherein the radiating plate of the first conductive arm is formed with a widening protruding plate extending toward a direction opposite to the connecting plate of the first conductive arm.

5. The multi-band antenna as claimed in claim 1, wherein the radiating plate of the second conductive arm is formed with a widening protruding plate extending toward a direction opposite to the connecting plate of the second conductive arm.

6. The multi-band antenna as claimed in claim 1, wherein the radiating plate of the first conductive arm is an elongated rectangular plate in the horizontal direction and the radiating plate of the second conductive arm is an elongated rectangular plate in the vertical direction.

7. The multi-band antenna as claimed in claim 1, wherein the radiating plate of the second conductive arm is an elongated rectangular plate in the horizontal direction and the radiating plate of the first conductive arm is an elongated rectangular plate in the vertical direction.

8. The multi-band antenna as claimed in claim 1, wherein the central wire is a positive signal wire and the outer wire is a negative signal wire.