Systems and methods that employ a balanced duplexer

• US 20050070232A1
• Filed: 09/26/2003
• Published: 03/31/2005
• Est. Priority Date: 09/26/2003
• Status: Active Grant

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Mages, Phil
• Granted Patent: US 7,123,883 B2
• Time in Patent Office: Days
• US Class Current: 455/78
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence
• CPC Class Codes: H04B 1/52 Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa

Abstract

The present invention relates to systems and methods that employ a novel balanced duplexer that can be utilized to facilitate concurrent signal transmission and reception. The systems and methods can be employed within mobile devices such as cell phones and utilize two-filters (e.g., acoustic) with substantially similar input/output impedances interfaced with two couplers (e.g., 3 dB hybrid), which provide isolation and maintain the duplexer'"'"'s input/output impedance. The couplers interface the filters to front/back ends such as signal processors, transmitters and receivers. The novel aspects of the present invention mitigate the need to employ external directional couplers between the duplexer and front/back ends. In addition, the two-filter topology enables employment of lower powered rated filters. The systems and methods further provide for separation and isolation of transmitters and receivers, which reduces noise coupling and enables the transmitter and receiver to be placed within close proximity.

Claims

1. A system that facilitates signal transmission and reception, comprising:

a first component configured to convey signals within a transmission and reception frequency band; and

a second component that interfaces the first component to a front-end and a back-end, the second component providing isolation between the first component and the front and back ends.

2. The system of claim 1, the first component provides concurrent signal transmission and reception.

3. The system of claim 1, the first component comprising two or more filters.

4. The system of claim 3, the two or more filters configured to determine the transmission and reception frequency band.

5. The system of claim 1, the second component comprising two 3 db hybrid couplers.

6. The system of claim 5, the 3 db hybrid couplers comprising at least one of a Lange coupler and a discrete coupler.

7. The system of claim 6, the Lange coupler comprising gold traces on a substrate.

8. The system of claim 1 employed within at least one of a mobile phone, a web phone, a personal data assistant (PDA), a hand-held PC, a pocket PC, a palm-pilot, a laptop, a tablet PC, a Notepad, a GPS, a pager, a personal computer, a mainframe, and a workstation.

9. A balanced duplexer, comprising:

a first filter;

a second filter, the first and second filters have a substantially similar input and output impedance;

a first coupler that interfaces the first and second filters to a processing unit of a device and a first termination; and

a second coupler that interfaces the first and second filters to an antenna, a detector and a second termination, the balanced duplexer is employed to facilitate transmitting and receiving signals through the first and second filters.

10. The system of claim 9, the first and second filters are employed such that a portion of the signal power is directed through one of the filters and the remaining signal power is directed through the other filter.

11. The system of claim 10, the portion of signal power directed to respective filters is determined by a power ratio.

12. The system of claim 10, the portion of signal power directed through respective filters is about one half the total power.

13. The system of claim 10, the first and second filters configured such that if one filter becomes inoperable, the other filter can be utilized to process the full signal power.

14. The system of claim 9, the balanced duplexer buffers an input and an output stage.

15. The system of claim 9, the first and second couplers being 3 dB hybrid couplers comprising one of a Lange coupler and a discrete coupler.

16. The system of claim 15, the Lange coupler providing isolation between the first and second filters and the processing unit and the first and second filters and the antenna and detector.

17. The system of claim 9, the first and second terminations is about 50Ω

.

18. The system of claim 9, the first and second filters comprising acoustic filters comprising SAW and BAW filters.

19. The system of claim 9 employed within at least one of a mobile phone, a web phone, a personal data assistant (PDA), a hand-held PC, a pocket PC, a palm-pilot, a laptop, a tablet PC, a Notepad, a GPS, a pager, a personal computer, a mainframe, and a workstation.

20. The system of claim 9, the first and second couplers divert reflected power into the first and second terminations, respectively.

21. The system of claim 9, the first and second couplers reduce reflected energy by combining reflected energy that is 180 degrees out of phase.

22. The system of claim 9, the first and second filters employed in the reception of a signal to improve LNA and antenna matching.

23. A methodology for transmitting signals, comprising:

conveying a generated signal to a balanced duplexer, the signal divided into two portions, a first portion with a first signal power transmitted through a first filter of the balanced duplexer and a remaining portion transmitted through a second filter, the remaining portion associated with a remaining signal power;

combining the first portion and second signal portions, and

transmitting the signal.

24. The method of claim 23, further comprising employing 3 dB hybrid couplers to divide and combine the generated signal.

25. The method of claim 24, further comprising providing isolation between the 3 dB hybrid couplers and a signal generating and a transmitting component.

26. A methodology for receiving signals, comprising:

accepting a signal;

conveying the signal to a balanced duplexer, the signal conveyed through at least one filter of the balanced duplexer, and

isolating the signal from a transmitted signal.

27. A system that facilitates concurrent signal transmission and reception via a balanced duplexer, comprising:

means for coupling a generated signal with the balanced duplexer;

means for coupling a received signal with the balanced duplexer;

means for isolating the generated signal from the received signal;

means for filtering the generated and received signals, and

means for diverting power reflections associated with the generated and received signals to terminations.