Dual radio antenna

• US 5,995,065 A
• Filed: 09/24/1997
• Issued: 11/30/1999
• Est. Priority Date: 09/24/1997
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Corporation
• Inventors: Kitchener, Dean, Robson, Julius George
• Primary Examiner(s): Le, Hoanganh
• Assistant Examiner(s): Malos, Jennifer H.
• Application Number:
  US08/936,314
• Time in Patent Office: 797 Days
• Field of Search: 343/725, 343/729, 343/745, 343/752, 343/895, 343/790, 343/791, 343/792
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 5/321 within a radiating element or between connected radiating elements
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence
• CPC Class Codes: H01Q 9/32 Vertical arrangement of element H01Q9/40 takes precedence
• CPC Class Codes: H01Q 9/36 with top loading

Abstract

This invention relates to an antenna operable in a multi-mode radio transceiver. One aspect of the present invention, provides a radio antenna having resonant frequencies operable to receive and transmit radio signals in different frequency bands according to two operating protocols.

Claims

1. A dual resonance radio antenna operable at two wavelengths λ

₁, and λ

₂, where λ

₁ and λ

₂ correspond to a higher operating frequency and a lower operating frequency respectively, comprising a single feed input, a monopole element having a length corresponding to λ

₂ /4 and a cylindrical element comprising a coaxial stub which surrounds a length of the monopole element having an electrical length corresponding to λ

₁ /4, the cylindrical element being electrically connected at the top of the monopole, providing the monopole with an exposed λ

₁ /4 length between the coaxial stub and the single feed input to the antenna;

wherein at the lower operating frequency, current is induced on the outer surface of the coaxial stub which is in phase with the exposed λ

₁ /4 section and the antenna performs as a quarter wave monopole; and

wherein at the higher operating frequency the coaxial stub presents a high impedance at the top of the monopole whereby the effective length of the monopole is λ

₁ /4, as measured from the single feed input to the antenna.

2. A dual resonance radio antenna according to claim 1 wherein the coaxial region of the stub is partially filled with a dielectric solid.

3. A dual resonance radio antenna according to claim 1 wherein the coaxial region of the stub is filled with a dielectric solid.

4. A method of operating a dual resonance radio antenna operable at two wavelengths λ

₁ and λ

₂, where λ

₁ and λ

₂ correspond to a higher operating frequency and a lower operating frequency respectively,

the antenna comprising a single feed input, a monopole element having a length corresponding to λ

₂ /4 and a cylindrical element comprising a coaxial stub which surrounds a length of the monopole element having an electrical length corresponding to λ

₁ /4, the cylindrical element being electrically connected at the top of the monopole, providing the monopole with an exposed λ

₁ /4 length between the coaxial stub and the single feed input of the antenna;

wherein at the lower operating frequency, current is induced on the outer surface of the coaxial stub which is in phase with the exposed λ

₁ /4 section and the antenna performs as a quarter wave monopole; and

wherein at the higher operating frequency the coaxial stub presents a high impedance at the top of the monopole whereby the effective length of the monopole is λ

₁ /4, as measured from the single feed input to the antenna.