US 12,316,284 B2
Multi-frequency low noise amplifier
Minjun He, Guangzhou (CN); and Yaohua Zheng, Guangzhou (CN)
Assigned to SMARTER MICROELECTRONICS (GUANG ZHOU) CO., LTD., Guangzhou (CN)
Filed by SMARTER MICROELECTRONICS (GUANG ZHOU) CO., LTD., Guangzhou (CN)
Filed on Sep. 4, 2022, as Appl. No. 17/929,708.
Application 17/929,708 is a continuation of application No. PCT/CN2021/131169, filed on Nov. 17, 2021.
Claims priority of application No. 202110187442.1 (CN), filed on Feb. 18, 2021.
Prior Publication US 2022/0416732 A1, Dec. 29, 2022
Int. Cl. H03F 3/191 (2006.01); H03F 1/26 (2006.01); H03F 1/56 (2006.01); H03F 3/195 (2006.01)
CPC H03F 1/565 (2013.01) [H03F 1/26 (2013.01); H03F 3/195 (2013.01); H03F 2200/111 (2013.01); H03F 2200/294 (2013.01); H03F 2200/451 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A multi-frequency low noise amplifier, comprising an input matching network, an amplifying circuit, and an output matching network, wherein
the input matching network comprises a first out-of-band rejection circuit and a first frequency band selection circuit; and the output matching network comprises a second out-of-band rejection circuit and a second frequency band selection circuit;
an input end of the first out-of-band rejection circuit is connected with a radio frequency input end, and an output end of the first out-of-band rejection circuit is connected with an input end of the first frequency band selection circuit;
an output end of the first frequency band selection circuit is connected with an input end of the amplifying circuit;
an output end of the amplifying circuit is connected with an input end of the second frequency band selection circuit, and an output end of the second frequency band selection circuit is connected with a radio frequency output end;
one end of the second out-of-band rejection circuit is connected with the second frequency band selection circuit, and another end of the second out-of-band rejection circuit is connected with a grounded junction;
the first out-of-band rejection circuit comprises a plurality of first branches arranged in parallel, and each of the first branches comprises a first variable capacitor and a first inductor arranged in series;
the first frequency band selection circuit comprises a plurality of second branches arranged in series, and each of the second branches comprises a second variable capacitor and a second inductor arranged in parallel;
the second frequency band selection circuit comprises a third inductor, a third variable capacitor and a fourth variable capacitor which are arranged in series;
the second out-of-band rejection circuit comprises a fourth inductor and a fifth variable capacitor which are arranged in series;
the first out-of-band rejection circuit is configured to reject signal of any frequency band in radio frequency signals such that signals of remaining frequency bands are enabled to pass through;
the first frequency band selection circuit is configured to screen out signals of reference frequency spots from the remaining frequency bands;
the second frequency band selection circuit is configured to screen out signals of partial frequency spots from the amplified signals of the reference frequency spots; and
the second out-of-band rejection circuit is configured to reject the signal of any frequency spot in the signals of the partial frequency spots, such that the multi-frequency low noise amplifier is enabled to output a signal of target frequency spot.