Broadband isolation low-loss ISM/MB-HB tunable diplexer

Patent metadata

Field	Value
Publication number	US-9985682-B2
Application number	US-201414523065-A
Country	US
Kind code	B2
Filing date	Oct 24, 2014
Priority date	Oct 24, 2013
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

Embodiments of a tunable radio frequency (RF) diplexer and methods of duplexing transmission and receive signals are disclosed. In one embodiment, the RF diplexer includes a first hybrid coupler, a second hybrid coupler, and an RF filter circuit, and a phase inversion component. Both the RF filter circuit and the phase inversion component are connected between the first hybrid coupler and the second hybrid coupler. In some embodiments, the phase inversion component is provided by the RF filter circuit, while in other embodiments, the phase inversion component is provided separately. The phase inversion component is configured to provide a differential phase shift. The benefit of introducing the differential phase shift is that it provides increased isolation and broadband isolation between the different frequency bands being diplexed by the RF diplexer.

First claim

What is claimed is:

1. A radio frequency (RF) diplexer comprising:
a first hybrid coupler;
a second hybrid coupler; and
an RF filter circuit connected between the first hybrid coupler and the second hybrid coupler, wherein the RF filter circuit comprises a phase inversion component, which comprises a first resonator having a first inductor, and a second resonator having a second inductor, wherein the first inductor and the second inductor are magnetically coupled and configured to provide approximately a differential phase shift between the first hybrid coupler and the second hybrid coupler.

2. The RF diplexer of claim 1 wherein:
the first hybrid coupler comprises:
a first port configured to be coupled to an antenna;
a second port configured to be coupled to external circuitry;
a third port coupled to the RF filter circuit; and
a fourth port coupled to the RF filter circuit; and

the second hybrid coupler comprises:
a fifth port coupled to the RF filter circuit;
a sixth port coupled to the RF filter circuit;
a seventh port coupled to other external circuitry; and
an eighth port configured to be coupled to an impedance termination.

3. The RF diplexer of claim 2 wherein the phase inversion component is connected between the fourth port of the first hybrid coupler and the sixth port of the second hybrid coupler.

4. The RF diplexer of claim 3 wherein:
a first S parameter is defined between the second port and the third port of the first hybrid coupler;
a second S parameter is defined between the second port and the fourth port of the first hybrid coupler;
a third S parameter is defined between the fifth port and the seventh port of the second hybrid coupler;
a fourth S parameter is defined between the sixth port and the seventh port of the second hybrid coupler; and
wherein the first S parameter multiplied by the third S parameter is substantially equal to the second S parameter multiplied by the fourth S parameter.

5. The RF diplexer of claim 4 wherein:
the first hybrid coupler is configured to:
provide no phase shift between the first port and the third port;
provide a quadrature phase shift between the first port and the fourth port; and
provide no phase shift between the second port and the fourth port; and

the second hybrid coupler is configured to:
provide no phase shift between the fifth port and the seventh port;
provide a quadrature phase shift between the fifth port and the eighth port;
provide a quadrature phase shift between the sixth port and the seventh port; and
provide no phase shift between the sixth port and the eighth port.

6. The RF diplexer of claim 1 wherein:
the RF filter circuit comprises a first RF filter and a second RF filter;
the first RF filter is connected between the first hybrid coupler and the second hybrid coupler; and
the second RF filter is connected between the first hybrid coupler and the second hybrid coupler wherein the second RF filter comprises the phase inversion component.

7. The RF diplexer of claim 6 wherein:
the first hybrid coupler comprises:
a first port configured to be coupled to an antenna;
a second port configured to be coupled to external circuitry;
a third port coupled to the RF filter circuit; and
a fourth port coupled to the RF filter circuit; and

the second hybrid coupler comprises:
a fifth port coupled to the RF filter circuit;
a sixth port coupled to the RF filter circuit;
a seventh port coupled to other external circuitry; and
an eighth port configured to be coupled to an impedance termination;

wherein the first RF filter is connected between the third port of the first hybrid coupler and the fifth port of the second hybrid coupler and the second RF filter is connected between the fourth port of the first hybrid coupler and the sixth port of the second hybrid coupler.

8. The RF diplexer of claim 6 wherein the second RF filter comprises an RF filter path having the first resonator and the second resonator.

9. The RF diplexer of claim 8 wherein the first RF filter comprises an other RF filter path having a third resonator and a fourth resonator, wherein the third resonator and the fourth resonator are weakly coupled such that an energy transfer factor between the third resonator and the fourth resonator is less than 10%.

10. The RF diplexer of claim 6 wherein the second RF filter comprises:
a first resonator having the first inductor; and
a second resonator having the second inductor, wherein the second inductor is magnetically coupled to the first inductor such that the first inductor and the second inductor form a first single-ended transformer, the first inductor and the second inductor being magnetically coupled to provide approximately the differential phase shift such that the first single-ended transformer is the phase inversion component.

11. The RF diplexer of claim 10 wherein the first RF filter comprises:
a third resonator having a third inductor; and
a fourth resonator having a fourth inductor, wherein the fourth inductor is magnetically coupled to the third inductor such that the third inductor and the fourth inductor form a second single-ended transformer.

12. The RF diplexer of claim 6 wherein the second RF filter comprises:
a first resonator having the first inductor configured to have a first inductor portion and a second inductor portion; and
a second resonator having the second inductor configured to have a third inductor portion and a fourth inductor portion; the second inductor is magnetically coupled to the first inductor so as to provide a first differential transformer, wherein the first differential transformer has the first inductor portion magnetically coupled to the fourth inductor portion and the second inductor portion magnetically coupled to the third inductor portion so as to provide approximately the differential phase shift such that the first differential transformer is the phase inversion component.

13. The RF diplexer of claim 12 wherein the first RF filter comprises:
a third resonator having a third inductor configured to have a fifth inductor portion and a sixth inductor portion; and
a fourth resonator having a fourth inductor configured to have a seventh inductor portion and an eighth inductor portion, the fourth inductor is magnetically coupled to the third inductor so as to provide a second differential transformer, wherein the second differential transformer has the fifth inductor portion magnetically coupled to the seventh inductor portion and the sixth inductor portion magnetically coupled to the eighth inductor portion.

14. The RF diplexer of claim 6 wherein the second RF filter comprises:
a first resonator having the first inductor configured to have a first inductor portion and a second inductor portion;
a second resonator having the second inductor configured to have a third inductor portion and a fourth inductor portion; the second inductor is magnetically coupled to the first inductor so as to provide a first differential transformer, wherein the first differential transformer has the first inductor portion magnetically coupled to the third inductor portion and the second inductor portion magnetically coupled to the fourth inductor portion; and
a third inductor magnetically coupled to the second inductor such that the third inductor and the second inductor form a first single-ended to differential transformer that is configured to provide approximately the differential phase shift so that the first single-ended to differential transformer is the phase inversion component.

15. The RF diplexer of claim 14 wherein

Assignees

• Qorvo Us Inc

Inventors

• Khlat Nadim
• Granger-Jones Marcus

Classifications

• H04B1/50 Primary

  using different frequencies for the two directions of communication · CPC title

• H04B1/0057

  using diplexing or multiplexing filters for selecting the desired band · CPC title

• H04L27/2085

  with more than one phase shift per symbol period · CPC title

• H04L5/08

  each combination of signals in different channels being represented by a fixed frequency · CPC title

• H04B10/556

  Digital modulation, e.g. differential phase shift keying [DPSK] or frequency shift keying [FSK] · CPC title