Parasitic element and PIFA antenna structure

• US 7,053,841 B2
• Filed: 07/31/2003
• Issued: 05/30/2006
• Est. Priority Date: 07/31/2003
• Status: Expired due to Fees

• Current Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kroegel, Robert A., Ponce de Leon, Lorenzo A.
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US10/631,233
• Publication Number:
  US 20050024272A1
• Time in Patent Office: 1,034 Days
• Field of Search: 343/700.MS, 343/702, 343/846
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/243 with built-in antennas
• 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 5/371 Branching current paths
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 9/0414 in a stacked or folded configuration
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

A Parasitic Element (202) for use in combination with a Planer Inverted “F” Antenna (PIFA) (100) that creates an additional band of efficient operation for the combined antenna structure (200). The parasitic element (202) is able to be made to conform to surfaces (704) that are near the PIFA, such as of a case (704) of a cellular telephone (706). The parasitic element (202) is positioned so as to radiantly couple with the PIFA (100) in order to create the additional band of efficient operation. A parasitic element (202) is used with a dual band PIFA that operates in two RF bands, such as in the region near 800 MHz and 1.9 GHz, and adds a third band such as in the region near 1.575 GHz to support reception of Global Positioning System signals. This parasitic element (202) can conform to a case (704) of the cellular telephone (706).

Claims

1. An antenna, comprising:

a PIFA for wireless operation within at least one frequency band; and

a parasitic element positioned to be operatively coupled to the PIFA, wherein the parasitic element is obmically isolated from ground, and wherein RF energy is radiantly coupled between the parasitic element and the PIFA, and the parasitic element is configured and positioned so as to further induce wireless operation of the PIFA within at least one additional frequency band;

wherein the PIFA is mounted above a ground plane, the PIFA having a first side facing a plane containing the ground plane and wherein the parasitic element is located above a second side of the PIFA that is opposite the first side.

2. The antenna of claim 1, wherein the parasitic element comprises three ohmically connected arms that join at substantially right angles and that radiantly couple to at least three arms of the PIFA.

3. The antenna of claim 1, wherein the parasitic element comprises three ohmically connected arms that are arranged in a shape that generally conforms to the shape of the PIFA.

4. The antenna of claim 1, wherein the parasitic element comprises a meandering section.

5. The antenna of claim 1, wherein the parasitic element conforms to a surface that is above the PIFA.

6. The antenna of claim 5, wherein the parasitic element is mounted on the surface, wherein the surface is between the PIFA and the parasitic element, the surface comprises at least a portion of a case of a wireless communications device.

7. The antenna according to claim 6, wherein the PIFA is in contact with a first side of the surface and the parasitic element is in contact with an opposite side of the surface, the opposite side being opposite the first side.

10. The method according to claim 7, wherein the parasitic element comprises three ohmically connected arms that are arranged in a shape that generally conforms to the shape of the PIFA antenna.

11. The method according to claim 7, wherein the parasitic element comprises a meandering section so as to further induce radiation characteristics of the PIFA antenna in an additional plurality of bands.

8. A parasitic element for use with a PIFA antenna that is for wireless operation within at least one frequency band, the parasitic element comprising:

at least two conductors arranged so as to radiantly couple RF energy between the parasitic element and the PIFA antenna,

wherein the parasitic element is configured and positioned relative to the PIFA antenna so as to further induce wireless operation of the PIFA antenna within at least one additional frequency band and wherein the parasitic element is ohmically isolated from ground;

wherein the parasitic element conforms to a surface that is above the PIFA and the parasitic element is mounted on the surface, wherein the surface is between the PIFA and the parasitic element, the surface comprises at least a portion of a case of a wireless communications device.

9. A method comprising:

parasitically inducing a radiation characteristic of a PIFA antenna, that wirelessly operates within at least one frequency band, resulting in wireless operation thereof within at least one additional frequency band by radiantly coupling RF energy from the PIFA antenna to a parasitic element that is ohmically isolated from ground;

wherein the parasitically inducing comprises positioning the parasitic element so as to be operatively coupled to the PIFA antenna so as to induce the radiant coupling of RF energy between the PIFA antenna and the parasitic element, wherein the positioning contributes to the parasitically inducing and wherein the parasitic element comprises a conductor ohmically isolated from around;

wherein the parasitic element conforms to a surface that is above the PIFA antenna and the parasitic element is mounted on the surface and the surface comprises at least a portion of a case of a wireless communications device.

12. A wireless communications device, comprising:

at least one of a receiver for wirelessly receiving transmitted signals and a transmitter for wirelessly transmitting signals;

a PIFA antenna, electrically coupled to the at least one of a receiver and a transmitter, for wireless operation within at least one frequency band; and

a parasitic element, positioned so as to be operatively coupled to the PIFA antenna, for radiantly coupling RF energy between the parasitic element and the PIFA antenna, the parasitic element being configured and positioned so as to further induce radiation of the PIFA antenna within at least one additional frequency band, wherein the parasitic element is ohmically isolated from ground;

wherein the parasitic element conforms to a surface that is above the PIFA and the surface comprises at least a portion of a case of the wireless communications device.

13. The wireless communications device of claim 12, wherein the parasitic element comprises three ohmically connected arms that are arranged in a shape that generally conforms to the shape of the PIFA antenna.