DUPLEXER

• US 20150222300A1
• Filed: 07/29/2013
• Published: 08/06/2015
• Est. Priority Date: 08/27/2012
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Epcos AG (TDK Corporation)
• Inventors: Schmidhammer, Edgar, Ellae, Juha
• Granted Patent: US 9,571,133 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 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
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex

Abstract

A duplexer having good insulation, small geometric dimensions and good decoupling of the transmit signal path from an antenna which may have poor matching is specified. To that end, the duplexer comprises two transmit filters, a receive filter and two 90° hybrids.

Claims

1. A duplexer comprising

an antenna terminal, a transmit terminal and a receive terminal,

two transmit filters and one receive filter and,

a first and a second 90°

hybrid, each hybrid having a first, second, third and fourth terminal,

the antenna terminal being interconnected with the first terminal of the first hybrid,

the receive filter being interconnected between the third terminal of the first hybrid and the receive terminal,

one of the transmit filters being interconnected between the fourth terminal of the first hybrid and the second terminal of the second hybrid,

the other one of the transmit filters being interconnected between the second terminal of the first hybrid and the fourth terminal of the second hybrid,

the transmit terminal being interconnected with the first terminal of the second hybrid.

2. The duplexer of claim 1,

the first terminals of the hybrids being input terminals and, between output signals of the second and fourth terminal of the hybrids, a phase difference of about 90°

being present.

3. The duplexer of claim 1, furthermore comprising an impedance element which interconnects the third terminal of the second hybrid with ground.

4. The duplexer of claim 1, wherein each of the hybrids outputs an RF power present at the first terminal in equal parts at terminals two and four.

5. The duplexer of claim 1, wherein the two hybrids have the same configuration and/or the two transmit filters have the same configuration.

6. The duplexer of claim 1, wherein receive signals

are conveyed from terminals two and four of the first hybrid to the transmit filters,

are reflected by the transmit filters and

are conveyed to the receive filter via the third terminal of the first hybrid.

7. The duplexer of claim 1, wherein transmit signals at the third terminal of the first duplexer cancel one another.

8. The duplexer of claim 1, wherein the standing wave ratio on the transmit path is subject to lower fluctuations in a transmit frequency band than on the receive path in a receive frequency band.

9. The duplexer of claim 1, wherein the transmit power is controlled by the envelope of the transmit signal in a control loop.

10. The duplexer of claim 1, further comprising

a first power amplifier, an in-phase power amplifier and a quadrature power amplifier,

a third and a fourth hybrid and

a switch arrangement, wherein

the in-phase power amplifier and the quadrature power amplifier are interconnected on parallel signal paths between the terminals two and four of the hybrids three and four and the switch arrangement interconnects the second terminals of the hybrids three and four either in each case with ground or with one another.

11. The duplexer of claim 1, wherein the center frequency of the second hybrid is moved towards the center frequency of a transmit frequency band.

12. The duplexer of claim 1, wherein at least one of the hybrids comprises coupled transformers.