Low-voltage and low-power Ku-band CMOS LNA using capacitive feedback

An ultra-wideband (12–18 GHz) low-noise amplifier (LNA) using a 65 nm CMOS technology is proposed, in which a common-source cascode structure with capacitive feedback technique is employed, leading to the excellent gain flatness. In order to provide the unconditional stability at all frequencies, a notch filter is placed in the input matching network. The post-layout simulation results confirm the S21 of 11.33 ± 0.33 dB, the input/output return loss of −7.5 to −32.7 dB and −10 to −17 dB, respectively. Moreover, reverse isolation (S12) better than 27 dB, noise figure (NF) of 4.6–5.47 dB and third-order input intercept point (IIP3) of −5.39 to −12.32 dB are obtained over the 12–18 GHz band of interest. The LNA power consumption, excluding the output buffer stage, is only 2.2 mW from a 0.8 V power supply. The LNA layout area is 0.255 mm2.