Method and apparatus for a tunable antenna

Patent metadata

Field	Value
Publication number	US-10122402-B2
Application number	US-201213732097-A
Country	US
Kind code	B2
Filing date	Dec 31, 2012
Priority date	Dec 31, 2012
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

A method for tuning an antenna comprising determining an operating frequency band of the antenna, and adjusting a capacitance of a tunable load according to the operating frequency band, wherein the tunable load is electromagnetically coupled to the antenna via a parasitic arm, and wherein the operating frequency band depends on the capacitance.

First claim

What is claimed is:

1. A method for tuning an antenna comprising:
determining an operating frequency band of the antenna, the antenna being a dual-arm antenna having arms of different lengths, the arms having ends that face each other without the arms overlapping; and
adjusting a capacitance of a tunable load according to the operating frequency band, the tunable load being electromagnetically coupled to the antenna via a loop-type parasitic arm disposed within a boundary of a keepout area laterally adjacent to a ground plane, the keepout area being a non-conductive region on a printed circuit board (PCB), and the operating frequency band depending on the capacitance.

2. The method of claim 1 , further comprising:
retrieving a capacitance value related to the operating frequency band of the antenna from a table stored in memory; and
wherein adjusting the capacitance further comprises adjusting the capacitance to the capacitance value retrieved from the table stored in memory.

3. The method of claim 2 , wherein the operating frequency band is one of a plurality of available operating frequency bands, and wherein the method further comprises:
determining a second operating frequency band of the antenna from among the plurality of available operating frequency bands; and
adjusting the capacitance of the tunable load according to the second operating frequency band.

4. The method of claim 1 , wherein the antenna resides on a housing and the loop-type parasitic arm resides on the PCB.

5. The method of claim 3 , wherein the tunable load comprises one of a variable capacitor, a digital tunable capacitor, a micro-electromechanical system (MEMS) capacitor array, and a varactor.

6. The method of claim 3 , wherein the capacitance of the tunable load is tunable in the range of about 1.8 picofarads (pF) to about 5 pF, wherein if the tunable load is about 1.8 pF an operating frequency low band is about 0.69 gigahertz (GHz) to about 0.75 GHz and an operating frequency high band is about 1.66 GHz to about 2.26 GHz, wherein if the tunable load is about 2.5 pF the operating frequency low band is about 0.81 GHz to about 0.89 GHz and the operating frequency high band is about 1.74 GHz to 2.27 GHz, and wherein if the tunable load is about 1.8 pF the operating frequency low band is about 0.87 GHz to about 0.96 GHz and the operating frequency high band is about 1.42 GHz to about 1.59 GHz.

7. An apparatus comprising:
a dual-arm antenna having arms of different lengths, the arms having ends that face each other without the arms overlapping;
a loop-type parasitic arm electromagnetically coupled to the dual-arm antenna, the loop-type parasitic arm disposed within a boundary of a keepout area laterally adjacent to a ground plane, the keepout area being a non-conductive region on a printed circuit board (PCB); and
a tunable load coupled to the loop-type parasitic arm, wherein a capacitance of the tunable load is variable and an operating frequency band of the dual-arm antenna depending on the capacitance.

8. The apparatus of claim 7 , wherein the tunable load is configured to receive a control signal and adjust the capacitance according to the control signal.

9. The apparatus of claim 8 , wherein the dual-arm antenna resides on the PCB and the loop-type parasitic arm resides on a housing that allows the dual-arm antenna to be physically separated from the PCB.

10. The apparatus of claim 8 , wherein the capacitance of the tunable load is tunable in the range of about 1.8 picofarads (pF) to about 5 picofarads, wherein if the tunable load is about 1.8 pF an operating frequency low band is about 0.69 gigahertz (GHz) to about 0.75 GHz and an operating frequency high band is about 1.66 GHz to about 2.26 GHz, wherein if the tunable load is about 2.5 pF the operating frequency low band is about 0.81 GHz to about 0.89 GHz and the operating frequency high band is about 1.74 GHz to 2.27 GHz, and wherein if the tunable load is about 1.8 pF the operating frequency low band is about 0.87 GHz to about 0.96 GHz and the operating frequency high band is about 1.42 GHz to about 1.59 GHz.

11. The apparatus of claim 10 , wherein the loop-type parasitic arm resides on the PCB and the dual-arm antenna resides on a housing that allows the dual-arm antenna to be physically separated from the PCB.

12. A wireless communication device comprising:
a dual-arm antenna having arms of different lengths, the arms having ends that face each other without the arms overlapping;
a loop-type parasitic arm electromagnetically coupled to the dual-arm antenna, the loop-type parasitic arm being disposed within a boundary of a keepout area laterally adjacent to a ground plane, the keepout area being a non-conductive region on a printed circuit board (PCB);
a tunable load coupled to the loop-type parasitic arm, a capacitance of the tunable load being variable and an operating frequency band of the dual-arm antenna depending on the capacitance; and
a processor coupled to the tunable load, the processor configured to select a first operating frequency band and set the capacitance to a value to achieve the first operating frequency band.

13. The wireless communication device of claim 12 , further comprising:
a memory coupled to the processor, the processor further configured to:
access a table stored in the memory, the table containing at least one capacitance value related to at least one operating frequency band; and
retrieve a capacitance value related to the first operating frequency band in the table,

wherein setting the capacitance to the value to achieve the first operating frequency band further comprises sending a control signal to the tunable load to set the capacitance to the capacitance value related to the first operating frequency band in the table.

14. The wireless communication device of claim 13 , wherein the first operating frequency band is selected from among a plurality of available operating frequency bands, and wherein the processor is further configured to:
select a second operating frequency band different from the first operating frequency band from among the plurality of available operating frequency bands; and
set the capacitance to a second value to achieve the second operating frequency band.

15. The wireless communication device of claim 13 , wherein the tunable load comprises one of a variable capacitor, a digital tunable capacitor, a micro-electromechanical system (MEMS) capacitor array, or a varactor.

16. The wireless communication device of claim 13 , wherein the loop-type parasitic arm and the tunable load reside on the PCB, and the dual-arm antenna does not reside on the PCB.

17. The wireless communication device of claim 13 , further comprising a proximity sensor coupled to the processor, the processor further configured to receive a proximity sensor measurement and take the proximity sensor measurement into account in selecting the first operating frequency band.

18. The wireless communication device of claim 13 , wherein the parasitic arm and the dual-arm antenna reside on one side of the PCB, and the loop-type parasitic arm couples to a ground plane on an opposing side of the PCB using a via.

19. A method for tuning an antenna comprising:
determining an operating frequency band of the antenna, the antenna being a dual-arm antenna having two arms of different lengths, the two arms having ends that face each other without the two arms overlapping; and
adjusting a capacitance of a tunable load according to the operating frequency band, the tunable load bein

Assignees

• Futurewei Technologies Inc

Inventors

• Yang Shing Lung Steven
• Shi Ping
• Kim Daejoung
• Toh Wee Kian
• Nader Navid
• Jiang Guangdong

Classifications

• H01Q5/392

  the parasitic elements having dual-band or multi-band characteristics · CPC title

• H01Q1/243

  with built-in antennas · CPC title

• H01Q9/06

  Details · CPC title

• H04B1/40 Primary

  Circuits · CPC title

• H01Q9/42 Primary

  with folded element, the folded parts being spaced apart a small fraction of the operating wavelength · CPC title