A Blocker-Tolerant K-Band LNA with 52-dB Ka-Band TX Rejection for Satellite Communications

This paper presents a blocker-tolerant K-band low-noise amplifier (LNA) in a 55-nm SOI CMOS process. A gain-flattening notch amplification unit is proposed to simultaneously enhance interference immunity and improve in-band gain flatness by exploiting parasitic effects. Furthermore, a hybrid passive filtering technique is introduced to realize comprehensive suppression of Ka-band transmitter (TX) leakage. Measurement results demonstrate a 3-dB bandwidth of 16.8–21.7 GHz with a peak gain of 29.5 dB and a minimum noise figure (NF) of 1.7 dB. Notably, an out-of-band (OOB) rejection of >52 dB is achieved. Drawing 10 mA from a 2.4-V supply, the LNA exhibits an in-band input 1-dB compression point (IP1dB) of better than -30 dBm, while the blocker IP1dB in the TX band (27.5–31 GHz) exceeds 0 dBm. The demonstrated superior blocker resilience makes the design highly suitable for compact multi-channel phased-array receivers in satellite communications.