ANTENNA SWITCHING IN A COMMUNICATION CIRCUIT

• US 20160119016A1
• Filed: 10/01/2015
• Published: 04/28/2016
• Est. Priority Date: 10/28/2014
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Khlat, Nadim
• Granted Patent: US 10,374,652 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 7/0602 using antenna switching H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/0686 Hybrid systems, i.e. switching and simultaneous transmission
• CPC Class Codes: H04B 7/0871 using different reception schemes, at least one of them being a diversity reception scheme
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex

Abstract

Aspects disclosed in the detailed description include antenna switching for a communication circuit. A communication circuit includes an antenna switching circuit that couples the communication circuit to a first antenna and/or a second antenna for radio frequency (RF) signal transmission and reception. The antenna switching circuit is configured to include fewer antenna switches compared to a conventional antenna switching circuit to reduce the cost and footprint of the communication circuit. Furthermore, by reducing the number of antenna switches in the antenna switching circuit, it is possible to improve RF isolation between the first antenna and the second antenna, thus leading to improved RF performance of the communication circuit.

Claims

1. A communication circuit, comprising:

a first radio frequency (RF) signal path configured to transmit a first RF signal during an assigned transmit (TX) period and receive a second RF signal during an assigned receive (RX) period temporally distinct from the assigned TX period;

a second RF signal path configured to receive the second RF signal during the assigned RX period; and

an antenna switching circuit configured to;

couple the first RF signal path to one of a first antenna and a second antenna to transmit the first RF signal during the assigned TX period;

couple the first RF signal path to the first antenna to receive the second RF signal during the assigned RX period; and

couple the second RF signal path to the second antenna to receive the second RF signal during the assigned RX period.

2. The communication circuit of claim 1 wherein:

the first RF signal is a time-division duplex (TDD) TX signal;

the second RF signal is a TDD RX signal; and

the assigned TX period and the assigned RX period alternate according to a TDD schedule.

3. The communication circuit of claim 1 wherein:

the first RF signal path comprises a transmit and receive (TX/RX) circuit configured to;

transmit the first RF signal via one of the first antenna and the second antenna; and

receive the second RF signal via the first antenna; and

the second RF signal path comprises an RX circuit configured to receive the second RF signal via the second antenna.

4. The communication circuit of claim 3 wherein:

the TX/RX circuit and the RX circuit coupled to a signal switching circuit that comprises a first signal switch and a second signal switch; and

the signal switching circuit configured to;

close the first signal switch and open the second signal switch to provide the first RF signal to the TX/RX circuit to transmit during the assigned TX period; and

open the first signal switch and close the second signal switch to receive the second RF signal from the TX/RX circuit during the assigned RX period.

5. The communication circuit of claim 4 wherein:

the antenna switching circuit comprises a first antenna switch, a second antenna switch, and a third antenna switch; and

the antenna switching circuit configured to;

close the first antenna switch, open the second antenna switch, and open the third antenna switch to couple the TX/RX circuit to the first antenna to transmit the first RF signal during the assigned TX period in response to a first antenna selection signal; and

open the first antenna switch, close the second antenna switch, and open the third antenna switch to couple the TX/RX circuit to the second antenna to transmit the first RF signal during the assigned TX period in response to a second antenna selection signal; and

close the first antenna switch, open the second antenna switch, and close the third antenna switch to couple the TX/RX circuit and the RX circuit to the first antenna and the second antenna, respectively, to receive the second RF signal during the assigned RX period in response to a third antenna selection signal.

6. The communication circuit of claim 1 wherein:

the first RF signal path comprises a first transmit and receive (TX/RX) circuit configured to transmit the first RF signal and receive the second RF signal via the first antenna; and

the second RF signal path comprises a second TX/RX circuit configured to transmit the first RF signal and receive the second RF signal via the second antenna.

7. The communication circuit of claim 6 wherein:

the first TX/RX circuit and the second TX/RX circuit further coupled to a signal switching circuit that comprises a first signal switch, a second signal switch, a third signal switch, and a fourth signal switch; and

the signal switching circuit configured to;

close the first signal switch, open the second signal switch, open the third signal switch, and open the fourth signal switch to provide the first RF signal to the first TX/RX circuit during the assigned TX period;

open the first signal switch, open the second signal switch, close the third signal switch, and open the fourth signal switch to provide the first RF signal to the second TX/RX circuit during the assigned TX period; and

open the first signal switch, close the second signal switch, open the third signal switch, and close the fourth signal switch to receive concurrently the second RF signal from the first TX/RX circuit and the second TX/RX circuit during the assigned RX period.

8. The communication circuit of claim 7 wherein:

the antenna switching circuit comprises a first antenna switch and a second antenna switch; and

the antenna switching circuit configured to;

close the first antenna switch and open the second antenna switch to couple the first TX/RX circuit to the first antenna to transmit the first RF signal during the assigned TX period in response to a first antenna selection signal;

open the first antenna switch and close the second antenna switch to couple the second TX/RX circuit to the second antenna to transmit the first RF signal during the assigned TX period in response to a second antenna selection signal; and

close the first antenna switch and close the second antenna switch to couple the first TX/RX circuit and the second TX/RX circuit to the first antenna and the second antenna, respectively, to receive the second RF signal during the assigned RX period in response to a third antenna selection signal.

9. The communication circuit of claim 1 wherein:

the first RF signal path comprises;

a first transmit and receive (TX/RX) circuit configured to;

transmit the first RF signal in a first RF band via one of the first antenna and the second antenna; and

receive the second RF signal in the first RF band via the first antenna; and

a second TX/RX circuit configured to;

transmit the first RF signal in a second RF band different from the first RF band via one of the first antenna and the second antenna; and

receive the second RF signal in the second RF band via the first antenna; and

the second RF signal path comprises;

a first RX circuit configured to receive the second RF signal in the first RF band via the second antenna; and

a second RX circuit configured to receive the second RF signal in the second RF band via the second antenna.

10. The communication circuit of claim 9 wherein:

the first TX/RX circuit, the second TX/RX circuit, the first RX circuit, and the second RX circuit coupled to a signal switching circuit that comprises a first signal switch, a second signal switch, a third signal switch, and a fourth signal switch; and

the signal switching circuit configured to;

close the first signal switch, open the second signal switch, open the third signal switch, and open the fourth signal switch to provide the first RF signal to the first TX/RX circuit to transmit in the first RF band during the assigned TX period;

open the first signal switch, open the second signal switch, close the third signal switch, and open the fourth signal switch to provide the first RF signal to the second TX/RX circuit to transmit in the second RF band during the assigned TX period; and

open the first signal switch, close the second signal switch, open the third signal switch, and close the fourth signal switch to receive concurrently the second RF signal in the first RF band from the first TX/RX circuit and the second RF signal in the second RF band from the second TX/RX circuit during the assigned RX period.

11. The communication circuit of claim 10 wherein:

the antenna switching circuit comprises a first antenna switch, a second antenna switch, and a third antenna switch; and

the antenna switching circuit configured to;

close the first antenna switch, open the second antenna switch, and open the third antenna switch to couple the first TX/RX circuit to the first antenna to transmit the first RF signal in the first RF band during the assigned TX period in response to a first antenna selection signal;

close the first antenna switch, open the second antenna switch, and open the third antenna switch to couple the second TX/RX circuit to the first antenna to transmit the first RF signal in the second RF band during the assigned TX period in response to a second antenna selection signal;

open the first antenna switch, close the second antenna switch, and open the third antenna switch to couple the first TX/RX circuit to the second antenna to transmit the first RF signal in the first RF band during the assigned TX period in response to a third antenna selection signal;

open the first antenna switch, close the second antenna switch, and open the third antenna switch to couple the second TX/RX circuit to the second antenna to transmit the first RF signal in the second RF band during the assigned TX period in response to a fourth antenna selection signal;

close the first antenna switch to couple the first TX/RX circuit and the second TX/RX circuit to the first antenna to receive concurrently the second RF signal in the first RF band and the second RF band during the assigned RX period in response to a fifth antenna selection signal; and

close the third antenna switch to couple the first RX circuit and the second RX circuit to the second antenna to receive concurrently the second RF signal in the first RF band and the second RF band during the assigned RX period in response to the fifth antenna selection signal.

12. The communication circuit of claim 1 wherein:

the first RF signal path comprises;

a first transmit and receive (TX/RX) circuit configured to transmit the first RF signal and receive the second RF signal in a first RF band via the first antenna; and

a second TX/RX circuit configured to transmit the first RF signal and receive the second RF signal in a second RF band different from the first RF band via the first antenna; and

the second RF signal path comprises;

a third TX/RX circuit configured to transmit the first RF signal and receive the second RF signal in the first RF band via the second antenna; and

a fourth TX/RX circuit configured to transmit the first RF signal and receive the second RF signal in the second RF band via the second antenna.

13. The communication circuit of claim 12 wherein:

the first TX/RX circuit, the second TX/RX circuit, the third TX/RX circuit, and the fourth TX/RX circuit coupled to a signal switching circuit that comprises a first signal switch, a second signal switch, a third signal switch, a fourth signal switch, a fifth signal switch, a sixth signal switch, a seventh signal switch, and an eighth signal switch; and

the signal switching circuit configured to;

close the first signal switch, close the fifth signal switch, and open all other signal switches to respectively provide the first RF signal to the first TX/RX circuit and the third TX/RX circuit to transmit concurrently in the first RF band during the assigned TX period;

close the third signal switch, close the seventh signal switch, and open all other signal switches to respectively provide the first RF signal to the second TX/RX circuit and the fourth TX/RX circuit to transmit concurrently in the second RF band during the assigned TX period;

close the second signal switch, close the fourth signal switch, close the sixth signal switch, close the eighth signal switch, and open all other signal switches to receive concurrently the second RF signal in the first RF band and the second RF band during the assigned RX period.

14. The communication circuit of claim 13 wherein:

the antenna switching circuit comprises a first antenna switch and a second antenna switch; and

the antenna switching circuit configured to;

close the first antenna switch and close the second antenna switch to transmit concurrently the first RF signal in the first RF band via the first antenna and the second antenna in response to a first antenna selection signal;

close the first antenna switch and close the second antenna switch to transmit concurrently the first RF signal in the second RF band via the first antenna and the second antenna in response to a second antenna selection signal; and

close the first antenna switch and close the second antenna switch to receive concurrently the second RF signal in the first RF band and the second RF band via the first antenna and the second antenna, respectively, in response to a third antenna selection signal.

15. A method for antenna switching, comprising:

transmitting a first radio frequency (RF) signal via one of a first antenna and a second antenna during an assigned transmit (TX) period; and

receiving a second RF signal concurrently from the first antenna and the second antenna during an assigned receive (RX) period temporally distinct from the assigned TX period.

16. The method of claim 15 further comprising:

transmitting the first RF signal in a first RF band via one of the first antenna and the second antenna during the assigned TX period;

transmitting the first RF signal in a second RF band different from the first RF band via one of the first antenna and the second antenna during the assigned TX period; and

receiving concurrently the second RF signal in the first RF band and the second RF band during the assigned RX period.

17. The method of claim 15 further comprising:

transmitting concurrently the first RF signal in a first RF band via the first antenna and the second antenna during the assigned TX period;

transmitting concurrently the first RF signal in a second RF band different from the first RF band via the first antenna and the second antenna during the assigned TX period; and

receiving concurrently the second RF signal in the first RF band and the second RF band during the assigned RX period.

18. The method of claim 15 further comprising alternating the assigned TX period and the assigned RX period according to a time-division duplex (TDD) schedule.