CPC H03H 9/205 (2013.01) [H03H 9/54 (2013.01); H03H 9/542 (2013.01); H03H 9/706 (2013.01); H04B 1/0057 (2013.01)] | 15 Claims |
1. A multiplexer, comprising:
a first filter port, a second filter port, a third filter port and a fourth filter port;
a first sub-filter having a first sub-filter port connected to the first filter port and a second sub-filter port connected to the second filter port;
a second sub-filter having a first sub-filter port connected to the first filter port and a second sub-filter port connected to the third filter port;
a third sub-filter having a first sub-filter port connected to the first filter port and a second sub-filter port connected to the fourth filter port;
a first acoustic resonator connected between the first filter port and ground; and
a second acoustic resonator connected between the second filter port and ground,
wherein the first, second and third sub-filters have contiguous passbands, with a bandwidth of one of the first, second or third sub-filters being equal to a bandwidth of the multiplexer,
wherein the first and second acoustic resonators are transversely-excited film bulk acoustic resonators (XBARs) that are configured to create respective transmission zeros adjacent to a lower edge of the bandwidth of the multiplexer.
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