A K-Band High Interference-Rejection GaAs Low-Noise Amplifier Using Multizero Control Method for Satellite Communication

This letter presents a 17.5-22.5-GHz low-noise amplifier (LNA) with the high out-of-band rejection in the range of 27.5-32.5 GHz and 4-10 GHz by using 90-nm GaAs p-HEMT technology. The multizero control method is proposed to produce multiple zeros for generating the high out-of-band rejection and expanding the rejection bandwidth. The multizero control is realized by bypass capacitor notch filters at the drain of transistors and shunt capacitor notch filters at the interstage matching circuits. By using this approach, the high rejection can be achieved at unwanted frequencies without additional devices. Also, the multizero control is mainly implemented in the transistor's bypass branch, which can achieve the low noise figure (NF) well within the whole operating band. The cost and integration of the front end can also be improved. The measured maximum gain is 23.9 dB at 19 GHz, and the 3-dB bandwidth is 17.5-22.5 GHz. The good interference rejection of the proposed LNA is from 57 to 73 dB and 61 to 72 dB in the range of 4-10 GHz and 27.5-32.5 GHz, respectively. The measured NF is 1.1-1.3 dB. The LNA area is 2 mm × 1.3 mm including pads.