Antenna operating in two frequency ranges

• US 6,054,966 A
• Filed: 06/05/1996
• Issued: 04/25/2000
• Est. Priority Date: 06/06/1995
• Status: Expired due to Fees

• Current Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Haapala, Paivi
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): PHAN, THO GIA
• Application Number:
  US08/658,620
• Time in Patent Office: 1,420 Days
• Field of Search: 343/702, 343/895, 343/866, 343/867, 343/722, 343/725, 343/749
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H01Q 5/40 Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence

Abstract

The invention relates to an antenna structure D with at least two resonance frequency bands. It comprises a first antenna element (P2; P3) which is preferably a straight conductor, and a second antenna element (HX3; HX4) which is preferably a conductor wound into a cylindrical coil, the antenna elements having different resonance frequencies. A rod element (P2; P3) is partly inside a helical element (HX3; HX4) and they can comprise the same feed point (A4) or separate feed points (A5; A6). The antenna can comprise a third antenna element (HX5) which is preferably a conductor wound into a cylindrical coil comprising a different resonance frequency from the other two antenna elements. The antenna according to the invention is well-adapted to be used in a mobile phone operating in at least two cellular telephone systems using different frequencies.

Claims

1. An antenna for transmitting and receiving radio frequency oscillations by using a radio transceiver, said antenna comprising:

a first antenna element which has a first input impedance and a first resonance frequency; and

a second antenna element which is a cylindrical coil conductor and has a second input impedance and a second resonance frequency that is different than said first resonance frequency,

wherein a part of said first antenna element is located inside said cylindrical coil conductor, and wherein the first and second antenna elements provide two respective different, separate and spaced operating frequency ranges, wherein the two different operating frequency ranges are separated from each other by at least about 400 MHz.

2. An antenna according to claim 1, characterized in that said first antenna element (P2;

P3) is a straight conductor.

3. An antenna according to claim 1, characterized in that the feed point (A4) of said first antenna element is the same as the feed point (A4) of said second antenna element.

4. An antenna according to claim 1, characterized in that the feed point (A5) of said first antenna element is not the same as the feed point (A6) of said second antenna element.

5. An antenna according to claim 4, characterized in that the feed point (A5) of said first antenna element is essentially on its longitudinal axis, and the feed point (A6) of said second antenna element is essentially on its cylindrical envelope.

6. An antenna according to claim 1, characterized in that it further comprises a third antenna element (HX5) whose resonance frequency is different to the resonance frequency of said first antenna element (P2;

P3) and different to the resonance frequency of said second antenna element (HX3;

HX4).

7. An antenna according to claim 6, characterized in that said third antenna element (HX5) is a cylindrical coil conductor.

8. An antenna according to claim 1, characterized in that it comprises a connecting part (L1) for connecting it mechanically and electrically to the radio set.

9. An antenna according to claim 1, characterized in that it comprises a protective cover (S1) of a dielectric material for protecting the said antenna elements (P2;

P3;

HX3;

HX4;

HX5).

10. An antenna according to claim 1, characterized in that at least one antenna element (P2;

P3;

HX3;

HX4;

HX5) is retractable within said radio set.

11. A radio telephone antenna assembly comprising:

a first antenna having a rod antenna element; and

a second antenna having a helical antenna element;

wherein the rod antenna element has a different resonance frequency than a resonance frequency of the helical antenna element, wherein the two resonance frequencies are spaced from each other;

wherein the rod antenna element extends along a center axis of the helical antenna element along the entire height of the helical antenna element;

wherein the first and second antennas are adapted to separately communicate with different types of radio telephone systems having different operating frequency ranges which are spaced from each other, wherein the different operating frequency ranges are spaced from each other by at least about 400 MHz, and wherein there is no significant alteration in a radiation pattern of the rod antenna element by the helical antenna element and there is no considerable change in a radiation pattern of the helical antenna element by the rod antenna element.

12. A method of communicating by a radio telephone with two different types of radio telephone systems having different operating frequency ranges, the method comprising steps of:

providing the radio telephone with an antenna assembly having a rod antenna element and a helical antenna element, the rod antenna element having a different resonance frequency than a resonance frequency of the helical antenna element, wherein the two resonance frequencies are spaced from each other by at least about 400 MHz, the rod antenna element extending along a center axis inside of the helical antenna element, and both the rod antenna element and helical antenna element are always electrically connected to at least one feed point for the antenna assembly; and

transmitting and receiving radio frequency signals at the rod antenna element with the first one of the different types of radio telephone systems;

wherein there is no considerable change in radiation patterns of the rod antenna element and the helical antenna element, due to their relative positioning, even though both antenna elements are always electrically connected to the same at least one feed point.