# US 6,297,784 B1 · Bi-frequency cellular telephone antenna

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- Number: US 6,297,784 B1
- Document ID: US6297784B1
- Status: Granted
- Kind: B1
- Application number: 09/184,260
- Filed: 1998-11-02
- Granted: 2001-10-02
- Earliest claimed: 1998-11-02
- Assignees: Auden Techno Corp.
- Inventors: Daniel Chang
- Web page: https://patentgrep.com/patent/US6297784B1

## CPC

- H01Q 11/08: Helical antennas
- H01Q 1/242: {specially adapted for hand-held use}
- H01Q 1/36: Structural form of radiating elements, e.g. cone, spiral, umbrella; {Particular materials used therewith}(H01Q1/08, H01Q1/14 take precedence)
- H01Q 5/371: Branching current paths
- H01Q 9/32: Vertical arrangement of element (H01Q9/40 takes precedence)
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

A bi-frequency cellular telephone antenna includes a shaft fastened to a cellular telephone, an insulative barrel fastened to the shaft at a top side, a first coil for a first frequency mounted inside the insulative barrel, and a second coil for a second frequency mounted around the periphery of the insulative barrel.

## Claims

### Claim 1

A bi-frequency cellular telephone antenna comprising:
a) a shaft configured to be fastened to a cellular telephone, the shaft having a stepped upper section formed by an upper smaller diameter portion and a lower, larger diameter portion, and an outward flange located below the stepped upper section;
b) a hollow, tubular insulative barrel fixedly mounted on the lower, larger diameter portion and extending therefrom so as to surround and be spaced from the upper, smaller diameter portion;
c) a first coil of metal wire for a first frequency mounted on the upper smaller diameter portion and located completely within the hollow insulative barrel; and,
d) a second coil of metal wire for a second frequency mounted on the outward flange and extending around a periphery of the insulative barrel.

### Claim 2 (depends on 1)

The bi-frequency cellular telephone antenna of claim 1 wherein the first and second coils have a match frequency f0 selected according to the formula: f 0 = 1 2 ⁢ π ⁢ LC
where:
L=inductance value
C=capacitance value

### Claim 3 (depends on 1)

The bi-frequency cellular telephone antenna of claim 1 wherein said first coil has a bottom end inserted into an annular space between said upper smaller diameter portion and said insulative barrel, and is supported on said lower larger portion.