Method and apparatus to control mutual coupling and correlation for multi-antenna applications

Patent metadata

Field	Value
Publication number	US-9722324-B2
Application number	US-201114005214-A
Country	US
Kind code	B2
Filing date	May 31, 2011
Priority date	Mar 15, 2011
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

The present invention provides a method and apparatus to manipulate the mutual coupling and the correlation between the antennas ( 502, 504 ) on the handset ( 202 ) without the need to change the physical distance between them or to change their orientation. The manipulation in the mutual coupling and in the correlation is achieved using a circuit that is connected between the antennas' terminals ( 506, 508 ) and the terminals ( 510, 512 ) of the RF front end/power amplifier ( 514 ). This circuit can be fixed or tunable. The coupling control takes place between two transmitting antennas ( 502, 504 ) or two receiving antennas ( 502, 504 ).

First claim

What is claimed is:

1. A communication device comprising:
a first antenna and a second antenna, having corresponding first antenna port and second antenna port respectively, the antenna ports operably coupled to respective first input/output (I/O) port and second I/O port;
a coupling compensation circuit comprised of independently configurable sections, the coupling compensation circuit coupled between the antenna ports and the I/O ports, wherein the sections are configured before operation to comprise:
first, second, third, fourth, fifth and sixth sections, each said section having a first end and a second end,
the respective first ends of the first section and the second section coupled to the respective first antenna port and second antenna port;
the second end of the first section coupled to the first end of the fifth section and the first end of the third section;
the second end of the second section coupled to the second end of the fifth section and the second end of the sixth section and the second end of the second section further coupled to the first end of the fourth section;
the second end of the sixth section being terminated to ground;
the respective second ends of the third and fourth sections being coupled to the respective first I/O port and second I/O port;
the first section and the second section each being configured to control a mutual coupling level and envelope correlation between the antenna ports;
the fifth and the sixth sections configured to optimize the mutual coupling of said configured first section and configured second section; and
the third section and the fourth section each being configured to provide an impedance match between the optimized fifth and sixth sections and the I/O ports, wherein adjustment of the sixth section provides an extra degree of freedom in controlling coupling currents in the antenna ports.

2. The communication device of claim 1 , further including switch elements for switching respective parts of one or more of the sections in or out of the compensation circuit to control tuning of the compensation circuit in operation of the antennas.

3. The communication device of claim 1 , wherein at least one of said first and second sections is tunable.

4. The communication device of claim 1 , wherein said coupling compensation circuit uses a hybrid combination of transmission lines and lumped elements.

5. The communication device of claim 1 , wherein said sixth section comprises an inductive and capacitive (LC) circuit.

6. The communication device of claim 1 , wherein said coupling compensation circuit uses only lumped elements.

7. The communication device of claim 6 , wherein said lumped elements comprises inductive and capacitive elements.

8. The communication device of claim 4 , wherein at least one of said sections comprises printed transmission traces.

9. The communication device of claim 8 , wherein said printed transmission traces are printed on an enhanced substrate.

10. The communication device of claim 8 , wherein said transmission traces have a variable impedance.

11. The communication device of claim 8 , wherein the impedance of said transmission traces is varied by changing the length of said traces.

12. The communication device of claim 8 , wherein the impedance of said printed traces is varied by changing the dielectric constant of an enhanced substrate.

13. The communication device of claim 1 , including a controller coupled to said compensation circuit for tuning at least one of said sections.

14. The communication device of claim 1 , wherein said fifth section is coupled between a series connection formed of said first and third sections and said second and fourth sections.

Assignees

• Ali Shirook M
• Warden James Paul
• Blackberry Ltd

Inventors

• Ali Shirook M
• Warden James Paul

Classifications

• H01Q21/28 Primary

  Combinations of substantially independent non-interacting antenna units or systems {(multiple beam H01Q25/00)} · CPC title

• H01Q1/523 Primary

  between antennas of an array · CPC title