Parallel hybrid acoustic passive filter
Aspects of this disclosure relate to a parallel hybrid acoustic passive filter. The parallel hybrid acoustic passive filter includes a first sub-filter and a second sub-filter. The first sub-filter includes a first acoustic resonator and a first non-acoustic passive component. The second sub-filter includes a second acoustic resonator and second first non-acoustic passive component. The first sub-filter and the second sub-filter are together arranged to filter a radio frequency signal. The parallel hybrid acoustic filter can be a band pass filter or a band stop filter, for example. Related multiplexers, wireless communication devices, and methods are disclosed.
1. A multiplexer with a parallel hybrid acoustic passive filter, the multiplexer comprising:
A first filter configured to filter a radio frequency signal, the first filter including a first sub-filter in parallel with a second sub-filter at an input common node and an output common node, the first sub-filter including at least a first shunt circuit and a second shunt circuit connected in parallel with each other, the first shunt circuit having at least a first shunt acoustic resonator in series with a first shunt inductor, the second shunt circuit having only a second shunt inductor, the second shunt inductor in parallel with the first shunt acoustic resonator and the first shunt inductor, and the second sub-filter including a third shunt circuit and a fourth shunt circuit in parallel with each other, and at least one capacitor in parallel with the third and fourth shunt circuits, the third shunt circuit having at least a second shunt acoustic resonator in series with a third shunt inductor, the fourth shunt circuit having only a fourth shunt inductor, the fourth shunt inductor in parallel with the second shunt acoustic resonator and the third shunt inductor;
a first series inductor connected to the input common node such that the first series inductor is in series with the first and second sub-filters;
a fifth shunt inductor connected to the input common node and a sixth shunt inductor connected to the output common node; and
a second filter coupled to the first and second common nodes.
2. The multiplexer of claim 1 wherein the first filter is a band pass filter.
3. The multiplexer of claim 2 wherein a frequency response of the first filter has a first sub-passband corresponding to the first sub-filter, a second sub-passband corresponding to the second sub-filter, and a notch at a notch frequency between the first sub-passband and a second sub-passband.
4. The multiplexer of claim 2 wherein the second filter is a band stop filter.
5. The multiplexer of claim 1 wherein the first sub-filter includes a series acoustic resonator in series with the first shunt acoustic resonator, the series acoustic resonator in parallel with an inductor.
6. The multiplexer of claim 5 wherein the second filter is a high pass filter.
7. The multiplexer of claim 1 wherein the second sub-filter includes a third shunt acoustic resonator.
8. The multiplexer of claim 1 wherein the first filter has a first passband, the second filter has a second passband, the first passband having a lower edge that is at a higher frequency than an upper edge of the second passband.
9. The multiplexer of claim 1 further comprising a third filter coupled to at least one of the first and second common nodes.
10. A parallel hybrid acoustic passive filter comprising:
a first sub-filter including at least a first shunt circuit and a second shunt circuit connected in parallel with each other, the first shunt circuit having at least a first shunt acoustic resonator in series with a first shunt inductor, the second shunt circuit having only a second shunt inductor, the second shunt inductor in parallel with the first shunt acoustic resonator and the first shunt inductor;
a second sub-filter coupled in parallel with the first sub-filter at in input common node and an output common node, the second sub-filter including a third shunt circuit and a fourth shunt circuit in parallel with each other, and at least one capacitor in parallel with the third and fourth shunt circuits, the third shunt circuit having at least a second shunt acoustic resonator in series with a third shunt inductor, the fourth shunt circuit having only a fourth shunt inductor the fourth shunt inductor in parallel with the second shunt acoustic resonator and the third shunt inductor;
a first series inductor connected to the input common node such that the first series inductor is in series with the first and second sub-filters;
a fifth shunt inductor connected to the input common node and a sixth shunt inductor connected to the output common node; and
the first sub-filter and the second sub-filter are arranged to filter a radio frequency signal.
11. The parallel hybrid acoustic passive filter of claim 10 wherein the first sub-filter and the second sub-filter are together arranged as a band pass filter having a passband.
12. The parallel hybrid acoustic passive filter of claim 10 wherein a frequency response of the parallel hybrid acoustic passive filter has a first sub-passband corresponding to the first sub-filter, a second sub-passband corresponding to the second sub-filter, and at least one notch at a notch frequency between the first sub-passband and a second sub-passband.
13. The parallel hybrid acoustic passive filter of claim 10 wherein the first sub-filter and the second sub-filter are together arranged as a band stop filter having a stop band.
14. The parallel hybrid acoustic passive filter of claim 10 wherein the first sub-filter includes bulk acoustic wave resonators that include the first shunt acoustic resonator.
15. The parallel hybrid acoustic passive filter of claim 10 wherein the first sub-filter includes a series acoustic resonator in series with the first shunt acoustic resonator, the series acoustic resonator in parallel with an inductor.
16. The parallel hybrid acoustic passive filter of claim 10 wherein the first sub-filter further includes a third shunt acoustic resonator.
17. The parallel hybrid acoustic passive filter of claim 10 wherein the second shunt inductor is part of an integrated passive device.
18. The parallel hybrid acoustic passive filter of claim 10 wherein the first sub-filter and the second sub-filter have different passbands.
19. The parallel hybrid acoustic passive filter of claim 10 wherein a lower bound of a passband of the parallel hybrid acoustic passive filter is at least 2 gigahertz.
20. A wireless communication device comprising:
A radio frequency front end including a filter configured to filter a radio frequency signal, the filter including a first sub-filter in parallel with a second sub-filter an input common node and an output common node, the first sub-filter including at least a first shunt circuit and a second shunt circuit connected in parallel with each other, the first shunt circuit having at least a first shunt acoustic resonator in series with a first shunt inductor, the second shunt circuit having only a second shunt inductor, the second shunt inductor in parallel with have the first shunt acoustic resonator and the first shunt inductor, and the second sub-filter including a third shunt circuit and a fourth shunt circuit in parallel with each other, and at least one capacitor in parallel with the third and fourth shunt circuits, the third shunt circuit having at least a second shunt acoustic resonator in series with a third shunt inductor, the fourth shunt circuit having only a fourth shunt inductor, the fourth shunt inductor in parallel with the second shunt acoustic resonator and the third shunt inductor;
a first series inductor connected to the input common node such that the first series inductor is in series with the first and second sub-filters;
a fifth shunt inductor connected to the input common node and a sixth shunt inductor connected to the output common node; and
an antenna in communication with the radio frequency front end.