SYSTEMS AND METHODS FOR REDUCING FILTER INSERTION LOSS WHILE MAINTAINING OUT-OF-BAND ATTENUATION

• US 20130273860A1
• Filed: 04/12/2013
• Published: 10/17/2013
• Est. Priority Date: 04/12/2012
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Pehlke, David Richard
• Granted Patent: US 9,397,721 B2
• Time in Patent Office: Days
• US Class Current: 455/78
• CPC Class Codes: H04B 1/1638 Special circuits to enhance selectivity of receivers not otherwise provided for resonant circuits H03H
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H
• CPC Class Codes: H04B 1/44 Transmit/receive switching
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

Disclosed are systems and methods for reducing filter insertion loss while maintaining out-of-band attenuation. In some embodiments, a system can be configured for processing of radio-frequency (RF) signals. The system can include a plurality of signal paths configured to accommodate multiple frequency bands, with each of the multiple bands having a passband. The system can further include a filter circuit disposed along each of the signal paths. At least one of the filter circuits can be segmented into two or more segments that substantially cover the passband corresponding to the filter circuit. The segmented filter circuit can be configured to provide a desired attenuation of out-of-band interferers and a desired insertion loss level. In some embodiments, the signal paths can include receive (Rx) paths.

Claims

1. A system for processing radio-frequency (RF) signals, the system comprising:

a plurality of signal paths configured to accommodate multiple frequency bands, each of the multiple bands having a passband; and

a filter circuit disposed along each of the signal paths, at least one of the filter circuits segmented into two or more segments that substantially cover the passband corresponding to the filter circuit, the at least one segmented filter circuit configured to provide a desired attenuation of out-of-band interferers and a desired insertion loss level.

2. The system of claim 1 wherein the signal paths include receive (Rx) paths.

3. The system of claim 2 wherein the Rx paths include Rx-only paths.

4. The system of claim 3 wherein the at least one segmented filter circuit includes a first segmented filter circuit and a second segmented filter circuit arranged in a receive-only duplexer configuration to provide improved out-of-band attenuation.

5. The system of claim 4 wherein the first and second segmented filter circuits are configured to provide frequency coverage for substantially the entire corresponding passband.

6. The system of claim 5 wherein the first and second segmented filter circuits are further configured so that a maximum channel bandwidth associated with the passband is within the separate passbands associated with the first and second segmented filter circuits.

7. The system of claim 4 wherein the receive-only duplexer configuration includes a diversity receive circuit of a front end system.

8. The system of claim 7 wherein the diversity receive circuit is configured to operate with a strong transmit (Tx) carrier suppression property.

9. The system of claim 4 wherein the segments of the at least one segmented filter circuit share a common Rx port and a duplex shared port.

10. The system of claim 4 further comprising a switch configured to allow selection of a band.

11. The system of claim 4 further comprising a duplexer configured to duplex outputs of the first and second segmented filter circuits and provide further frequency dependent selective combining to yield a common output.

12. The system of claim 4 wherein the receive-only duplexer configuration includes a duplex function that is substantially symmetric with respect to placement of a half-wave element at a shared antenna port, or placed entirely on one or the other Rx side.

13. The system of claim 1 wherein the multiple frequency bands include bands B1, B2, B3 and B4 associated with a 3GPP communication standard.

14. The system of claim 13 wherein transmit and receive passbands associated with the bands B1, B3 and B4 are consolidated with four passbands.

15. The system of claim 13 wherein the bands B3 and B4 are partitioned in a selected manner to yield a Tx-Rx duplexing configuration having a decreased passband bandwidth and an increased duplex gap to yield a decreased insertion loss and an improved out-of-band attenuation.

16. The system of claim 13 wherein the bands B1, B2, B3 and B4 are partitioned such that the Rx bands are broken up and covered in pieces.

17. The system of claim 16 wherein the pieces of frequency segments are consolidated based on overlap bands and possible location of simultaneous Tx carrier frequencies to improve isolation from Tx carrier desense nonlinear effects.

18. The system of claim 1 wherein the signal paths include at least one transmit (Tx) path.

19. A radio-frequency (RF) module comprising:

a packaging substrate configured to receive a plurality of components;

a filter system disposed on the packaging substrate and having a plurality of filter circuits configured to accommodate multiple frequency bands, at least one of the filter circuits segmented into two or more segments that substantially cover a passband associated with the segmented filter circuit to provide a desired attenuation of out-of-band interferers and a desired insertion loss level; and

a plurality of connectors configured to provide electrical connections between the filter system and the packaging substrate.

20. A radio-frequency (RF) device comprising:

a transceiver configured to process RF signals in multiple frequency bands;

one or more antennas in communication with the transceiver to facilitate transmission and reception of the RF signals; and

a filter system connectable to the transceiver and the one or more antennas, the filter system having a plurality of filter circuits configured to accommodate the multiple frequency bands, at least one of the filter circuits segmented into two or more segments that substantially cover a passband associated with the segmented filter circuit to provide a desired attenuation of out-of-band interferers and a desired insertion loss level.