RF DUPLEXING DEVICE

• US 20130176912A1
• Filed: 12/26/2012
• Published: 07/11/2013
• Est. Priority Date: 01/10/2012
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Khlat, Nadim
• Granted Patent: US 9,319,208 B2
• Time in Patent Office: Days
• US Class Current: 370/277
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex

Abstract

Radio frequency (RF) duplexing devices and methods of operating the same are disclosed. In one embodiment, an RF duplexing device includes a transmission port, a receive port, a first duplexer, and a second duplexer. The first duplexer is coupled to the transmission port and the receive port, and is configured to provide a first phase shift from the transmission port to the receive port. The second duplexer is also coupled to the transmission port and the receive port. However, the second duplexer is configured to provide a second phase shift that is differential to the first phase shift from the transmission port to the receive port. By providing the second phase shift so that the second phase shift is differential to the first phase shift, the RF duplexing device can provide isolation through cancellation without needing to introduce significant insertion losses.

Claims

1. A radio frequency (RF) duplexing device comprising:

a transmission port;

a receive port;

a first antenna port;

a second antenna port;

a first duplexer coupled to the transmission port, the receive port, the first antenna port, and the second antenna port, wherein the first duplexer is configured to provide a first phase shift from the transmission port to the receive port; and

a second duplexer coupled to the transmission port and the receive port, wherein the second duplexer is configured to provide a second phase shift that is differential to the first phase shift from the transmission port to the receive port.

2. The RF duplexing device of claim 1 wherein:

the transmission port is operable to input an RF transmission signal;

the first antenna port is operable to output the RF transmission signal;

the second antenna port is operable to input an RF receive signal; and

the receive port is operable to output the RF receive signal.

3. The RF duplexing device of claim 1 wherein the first antenna port and the second antenna port are operably associated so that electromagnetic isolation between the first antenna port and the second antenna port is above an electromagnetic isolation level.

4. The RF duplexing device of claim 3 wherein the electromagnetic isolation level is greater than approximately 6 decibels.

5. The RF duplexing device of claim 1 wherein the first antenna port and the second antenna port are operably associated so that mutual coupling between the first antenna port and the second antenna port presents a mutual impedance between the first antenna port and the second antenna port.

6. The RF duplexing device of claim 5 further comprising:

a first tuning port;

a second tuning port, wherein the second duplexer is further coupled to the first tuning port and the second tuning port; and

a tuner having a tuner impedance and coupled between the first tuning port and the second tuning port, wherein the tuner is tunable to provide the tuner impedance so that the tuner impedance matches the mutual impedance presented between the first antenna port and the second antenna port.

7. The RF duplexing device of claim 6 further comprising:

a second tuner having a second tuner impedance and coupled to the first tuning port wherein the second tuner is tunable to provide the second tuner impedance so that the second tuner impedance matches a first antenna impedance presented at the first antenna port; and

a third tuner having a third tuner impedance and coupled to the second tuning port wherein the third tuner is tunable to provide the third tuner impedance so that the third tuner impedance matches a second antenna impedance presented at the second antenna port.

8. The RF duplexing device of claim 7 further comprising:

a first bidirectional coupler configured to couple the first antenna port and the first tuning port; and

a second bidirectional coupler configured to couple the second antenna port and the second tuning port.

9. The RF duplexing device of claim 7 further comprising:

a first single-pole antenna configured to emit an RF transmission signal within an RF transmission band that is output from the first antenna port, wherein the first single-pole antenna is configured to present the first antenna impedance at the first antenna port; and

a second single-pole antenna configured for reception of an RF receive signal within an RF receive band that is input into the second antenna port, wherein the second single-pole antenna is configured to present the second antenna impedance at the second antenna port.

10. The RF duplexing device of claim 7 further comprising:

a dual-pole antenna having a first feed port coupled to the first antenna port and a second feed port coupled to the second antenna port, wherein the dual-pole antenna is configured to;

emit an RF transmission signal within an RF transmission band that is received at the first feed port from the first antenna port;

present the first antenna impedance at the first antenna port from the first feed port;

provide reception for an RF receive signal within an RF receive band and transmit the RF receive signal to the second feed port so that the RF receive signal is input into the second antenna port; and

present the second antenna impedance at the second antenna port from the second feed port.

11. The RF duplexing device of claim 6 wherein:

the first duplexer and the second duplexer are configured to provide a third phase shift from the first antenna port to the first tuning port in a first signal direction; and

the first duplexer and the second duplexer are configured to provide a fourth phase shift from the second antenna port to the second tuning port in a second signal direction, wherein the fourth phase shift is differential to the third phase shift.

12. The RF duplexing device of claim 11 wherein the third phase shift is substantially equal to the first phase shift, and the fourth phase shift is substantially equal to the second phase shift.

13. The RF duplexing device of claim 6 wherein:

the first duplexer comprises;

a first RF filter coupled between the second antenna port and the receive port, wherein the first RF filter has a first frequency response defining a first stopband that blocks an RF transmission band; and

a second RF filter coupled between the transmission port and the first antenna port, wherein the second RF filter has a second frequency response defining a second stopband that blocks an RF receive band; and

the second duplexer comprises;

a third RF filter coupled between the second tuning port and the receive port, wherein the third RF filter has a third frequency response defining a third stopband that blocks the RF receive band; and

a fourth RF filter coupled between the transmission port and the first tuning port, wherein the fourth RF filter has a fourth frequency response defining a fourth stopband that blocks the RF transmission band.

14. The RF duplexing device of claim 13 wherein:

the first duplexer includes a non-inverting transformer coupled between the first RF filter and the transmission port; and

the second duplexer includes an inverting transformer coupled between the fourth RF filter and the transmission port, wherein the inverting transformer is configured to provide a polarity inversion such that the second phase shift is differential to the first phase shift.

15. The RF duplexing device of claim 1 wherein the second duplexer is transposed with respect to the first duplexer.

16. The RF duplexing device of claim 1 wherein:

the first duplexer includes a non-inverting transformer coupled to the transmission port; and

the second duplexer includes an inverting transformer coupled to the transmission port wherein the inverting transformer is configured to provide a polarity inversion such that the second phase shift is differential to the first phase shift.

17. The RF duplexing device of claim 16 further comprising a first RF filter having a first frequency response defining a first stopband that blocks an RF receive band, and a second RF filter having a second frequency response defining a second stopband that blocks an RF transmission band, wherein:

the non-inverting transformer comprises;

a first primary winding coupled to the transmission port; and

a first secondary winding coupled to the first RF filter; and

the inverting transformer comprises;

a second primary winding coupled to the transmission port; and

a second secondary winding coupled to the second RF filter.

18. The RF duplexing device of claim 1 further comprising a tuning port coupled to the second duplexer, and wherein:

the transmission port is operable to input an RF transmission signal that operates within an RF transmission band and to input spurious transmission noise emissions outside of both the RF transmission band and an RF receive band;

the receive port is operable to output an RF receive signal that operates within the RF receive band;

the first duplexer is configured to pass the RF transmission signal from the transmission port to the first antenna port; and

the first duplexer and the second duplexer are operably associated so as to split the spurious transmission noise emissions into a first hybrid noise signal that propagates from the transmission port to the receive port through the first duplexer, a second hybrid noise signal that propagates from the transmission port to the receive port through the second duplexer, and a third hybrid noise signal that propagates from the transmission port to the tuning port through the second duplexer, wherein the first hybrid noise signal is outside both the RF transmission band and the RF receive band, the second hybrid noise signal is outside both the RF transmission band and the RF receive band, and the third hybrid noise signal is within the RF receive band;

wherein the first phase shift provided by the first duplexer to the first hybrid noise signal from the transmission port to the receive port and the second phase shift provided by the second duplexer to the second hybrid noise signal from the transmission port to the receive port result in the first hybrid noise signal and the second hybrid noise signal substantially cancelling at the receive port.

19. The RF duplexing device of claim 1 wherein the first duplexer and the second duplexer are formed in one or more semiconductor substrates.

20. A method of duplexing, comprising:

inputting an RF receive signal at a first antenna port of a first duplexer;

inputting an RF transmission signal at a transmission port, wherein the transmission port is coupled to the first duplexer and to a second duplexer;

while inputting the RF receive signal at the first antenna port, outputting the RF transmission signal at a second antenna port of the first duplexer;

outputting the RF receive signal from a receive port, wherein the receive port is coupled to the first duplexer and the second duplexer;

providing a first phase shift from the transmission port to the receive port through the first duplexer while the RF transmission signal is being input at the transmission port and while the RF receive signal is being output from the receive port; and

providing a second phase shift from the transmission port to the receive port through the second duplexer while the RF transmission signal is being input at the transmission port and while the RF receive signal is being output from the receive port, wherein the second phase shift is differential to the first phase shift from the transmission port to the receive port.