US 11,916,529 B2
Matching circuit
Yusuke Tanaka, Kyoto (JP); and Hiroki Shounai, Kyoto (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed on Oct. 11, 2017, as Appl. No. 15/730,128.
Claims priority of application No. 2016-201146 (JP), filed on Oct. 12, 2016; and application No. 2017-000664 (JP), filed on Jan. 5, 2017.
Prior Publication US 2018/0102754 A1, Apr. 12, 2018
Int. Cl. H03H 7/38 (2006.01)
CPC H03H 7/38 (2013.01) 6 Claims
OG exemplary drawing
 
1. A matching circuit that performs output impedance matching for an amplifier, the matching circuit comprising:
a low pass filter comprising a shared ground and a plurality of parallel-connected capacitors, the plurality of parallel-connected capacitors being connected from a common node on a signal line to the shared ground in order to attenuate a second harmonic component of an amplified signal;
a high pass filter connected to the low pass filter, the high pass filter configured to cancel out a change of an impedance of the low pass filter; and
a parallel resonant circuit connected to the high pass filter to receive the amplified signal with the second harmonic component attenuated, the parallel resonant circuit configured to attenuate a third harmonic component of the received amplified signal,
wherein the shared ground of the plurality of parallel-connected capacitors of the low pass filter and a ground of the high pass filter are isolated from each other in order to prevent the third harmonic component of the amplified signal attenuated by the low pass filter from entering the high pass filter, and
wherein the shared ground of the low pass filter and a ground of the amplifier are isolated from each other, the low pass filter comprising the plurality of parallel-connected capacitors connected from the common node.