Transversely-excited film bulk acoustic resonator matrix filters with switches in parallel with sub-filter shunt capacitors

Patent metadata

Field	Value
Publication number	US-11955951-B2
Application number	US-202217948170-A
Country	US
Kind code	B2
Filing date	Sep 19, 2022
Priority date	Oct 5, 2020
Publication date	Apr 9, 2024
Grant date	Apr 9, 2024

Abstract

There are disclosed matrix filters having an input port and sub-filters connected between the input port and respective output ports. Each of the sub-filters includes a ladder circuit with n transversely-excited film bulk acoustic resonator (XBAR) series elements and n−1 capacitor shunt elements, where n, the order of the sub-filter, is an integer greater than 2. Each sub-filter further has a first switch in parallel with a first capacitor shunt element and a second switch in parallel with a last capacitor shunt element.

First claim

It is claimed:

1. A matrix filter, comprising:
a filter input port; and
two or more sub-filters connected between the filter input port and respective filter output ports, each sub-filter comprising n transversely-excited film bulk acoustic resonator (XBAR) series elements and at least one capacitor shunt element,
wherein n is an integer greater than 2, and
wherein each sub-filter further comprises at least one switch in parallel with the at least one capacitor shunt element.

2. The filter of claim 1 , wherein the two or more sub-filters have noncontiguous passbands[HL and wherein each of the noncontiguous passbands is a passband of only one sub-filter of the two or more sub-filters.

3. The filter of claim 2 , wherein the two or more sub-filters have contiguous passbands.

4. The filter of claim 1 , wherein only one sub-filter of the two or more sub-filters is selected to be connected between the filter input port and at least one filter output port of the respective filter output ports, and wherein no single sub-filter of the two or more sub-filters has an input-output transfer function that crosses an input-output transfer function of any other single sub-filter of the two or more sub-filters at a frequency where both respective input-output transfer functions are above −20 dB.

5. The filter of claim 1 , wherein each of the two or more sub-filters have noncontiguous passbands separated by a stop band that exists where an input-output transfer function of the matrix filter is less than −20 dB; and wherein sub-filter connections between the filter input port and the respective filter output ports is configured to be switched to select one or more of the noncontiguous passbands.

6. The filter of claim 1 , wherein the at least one capacitor shunt element is between one of:
a) an XBAR series element of the n XBAR series elements that is immediately adjacent to the filter input port and an XBAR series element of the n XBAR series elements that is farther from the filter input port; or
b) an XBAR series element of the n XBAR series elements that is immediately adjacent to a filter output port of the respective filter output ports and an XBAR series element of the n XBAR series elements that is farther from the filter output port of the respective filter output ports.

7. The filter of claim 6 , wherein the n XBAR series elements include a first end XBAR connected to a first sub-filter port, a second end XBAR connected to a second sub-filter port, and one or more middle XBARs connected between the first end XBAR and the second end XBAR.

8. The filter of claim 1 , wherein each of the respective filter output ports is connected to a common output port.

9. The filter of claim 1 , wherein:
each of the XBAR series elements is connected in series between a first sub-filter port and a second sub-filter port;
each of the at least one capacitor shunt element is connected between ground and a node between a respective pair of XBAR series elements of the n XBAR series elements; and
each of the at least one switches is connected between ground and the node between the respective pair of XBAR series elements of then XBAR series elements.

10. A filter, comprising:
a first filter port and a second filter port; and
n sub-filters, where n is an integer greater than one, each of the n sub-filters having a first sub-filter port connected to the first filter port and a second sub-filter port connected to the second filter port;
wherein each sub-filter comprises at least three transversely-excited film bulk acoustic resonator (XBAR) series elements and at least one capacitor shunt element;
wherein each of the n sub-filters further comprise at least one switch in parallel with the at least one capacitor shunt element.

11. The filter of claim 10 , wherein the n sub-filters have noncontiguous passbands, and wherein each of the noncontiguous passbands is the passband of only one sub-filter of the n sub-filters.

12. The filter of claim 10 , wherein each of the n sub-filters has a noncontiguous passband separated from the passband of all of the other n sub-filters by a stop band that exists where an input-output transfer function of the filter is less than −20 dB.

13. The filter of claim 10 , wherein only one sub-filter of the n sub-filters is selected to be connected between the first filter port and the second filter port, and wherein no single sub-filter of the n sub-filters has an input-output transfer function that crosses an input-output transfer function of any other single sub-filter of the n sub-filters at a frequency where both respective input-output transfer functions are above −20 dB.

14. The filter of claim 10 , wherein the passband of the filter is selected to be equal to only one of the noncontiguous passbands of the n sub-filters.

15. The filter of claim 10 , wherein:
each of the XBAR series elements is connected in series between the first sub-filter port and the second sub-filter port;
each of the at least one capacitor shunt element is connected between ground and a node between a respective pair of XBAR series elements of the at least three XBAR series elements; and
each of the at least one switches is connected between ground and the node between the respective pair of XBAR series elements of the at least three XBAR series elements.

16. The filter of claim 15 , wherein:
the XBAR series elements each include a first end XBAR connected to the first sub-filter port, a second end XBAR connected to the second sub-filter port, and one or more middle XBARs connected between the first end XBAR and the second end XBAR, and
the at least one capacitor shunt element is between one of:
a) an XBAR series element of the XBAR series elements that is immediately adjacent to the first sub-filter port and an XBAR series element of the XBAR series elements that is farther from the first sub-filter port; or
b) an XBAR series element of the XBAR series elements that is immediately adjacent to the second sub-filter port and an XBAR series element of the XBAR series elements that is farther from the second sub-filter port.

17. A three-band diversity receiver, comprising:
a matrix triplexer coupled between an antenna and three receivers, the triplexer comprising;
a first sub-filter coupled between a first filter port and a second filter port coupled to a first receiver of the three receivers;
a second sub-filter coupled between the first filter port and a third filter port coupled to a second receiver of the three receivers;
a third sub-filter coupled between the first filter port and a fourth filter port coupled to a third receiver of the three receivers;
wherein each sub-filter comprises at least three transversely-excited film bulk acoustic resonator (XBAR) series elements and at least one capacitor shunt element;

wherein each sub-filter further comprises at least one switch in parallel with the at least one capacitor shunt element.

18. The filter of claim 17 , wherein the first, second and third sub-filters each have a noncontiguous passband separated from the passband of all of the others of the first, second and third sub-filters by a stop band that exists where an input-output transfer function of the matrix triplexer is less than −20 dB.

19. The filter of claim 17 , wherein:
each of the XBAR series elements is connected in series between the first sub-filter port and the second sub-filter port;
each of the at least one capacitor shunt element is connected between ground and a node between a respective pair of XBAR series elements of

Assignees

• Murata Manufacturing Co

Inventors

• Guyette Andrew
• Fenzi Neal
• Eddy Michael
• Garcia Bryant

Classifications

• H03H9/568 Primary

  consisting of a ladder configuration · CPC title

• H03H9/17

  having a single resonator (crystal tuning forks H03H9/21) · CPC title

• H03H9/542

  including passive elements (H03H9/545 takes precedence) · CPC title

• H03H9/02228 Primary

  Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer · CPC title

• H03H9/564

  implemented with thin-film techniques · CPC title