US 11,817,893 B2
Hybridized wideband notch filter topologies and methods
William Richard Smith, Jr., Lake in the Hills, IL (US); Muhammed Ibrahim Sezan, Carlsbad, CA (US); and Dan William Nobbe, Crystal Lake, IL (US)
Assigned to pSemi Corporation, San Diego, CA (US)
Filed by pSemi Corporation, San Diego, CA (US)
Filed on Mar. 29, 2021, as Appl. No. 17/216,457.
Prior Publication US 2022/0311464 A1, Sep. 29, 2022
Int. Cl. H04B 1/10 (2006.01); H04B 1/04 (2006.01)
CPC H04B 1/1036 (2013.01) [H04B 1/0483 (2013.01); H04B 2001/1063 (2013.01); H04B 2001/1072 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A radio frequency filter circuit based on a plurality of acoustic wave resonators (AWR) and having a specified notch band and a specified passband, the radio frequency filter circuit and including:
(a) at least one series-arm each including:
(1) a series-arm AWR having an electrostatic capacitance CO and selected to have a resonance frequency and an anti-resonance frequency associated with the series- arm AWR, wherein the anti-resonance frequency is within the specified notch band, and the resonance frequency and the anti-resonance frequency are both spaced apart in frequency from the specified passband; and
(2) a series-arm matching inductor coupled in series with the series-arm AWR to form a first inductor-capacitor circuit and having an inductance value that resonates with the electrostatic capacitance C0 of the series-arm AWR within the specified passband; and
(b) at least one parallel-arm coupled to the at least one series-arm and including:
(1) a parallel-arm AWR having an electrostatic capacitance C0 and selected to have a resonance frequency and an anti-resonance frequency associated with the parallel-arm AWR, wherein the resonance frequency is within the specified notch band, and the resonance frequency and the anti-resonance frequency are both spaced apart in frequency from the specified passband; and
(2) a parallel-arm matching inductor coupled in parallel with the parallel-arm AWR to form a second inductor-capacitor circuit and having an inductance value that resonates with the electrostatic capacitance CO of the parallel-arm AWR within the specified passband;
wherein the anti-resonance frequency of the at least one series-arm and the anti-resonance frequency of the coupled at least one parallel-arm are selected to form a notch filter;
wherein the first inductor-capacitor circuit and the selection of the resonance and anti-resonance frequencies of the at least one series-arm AWR spaced apart from the specified passband makes the at least one series-arm AWR behave like a short-circuit within the specified passband;
wherein the second inductor-capacitor circuit and the selection of the resonance and anti-resonance frequencies of the at least one parallel-arm AWR spaced apart from the specified passband makes the at least one parallel-arm AWR behave like an open circuit within the specified passband.