A K-to-Ka Band Ultra Wideband Power Amplifier in 180-Nm SiGe Technology

This paper presents a power amplifier (PA) fabricated in a 180nm Huahong SiGe technology, which can fully cover the K- and Ka-band and delivers a saturated output power of about 18 dBm. The amplifier adopts Cascode structure to achieve higher output power, better reverse isolation and stability. The two-stage differential cascade structure, combined with the transformer for good circuit matching, improves the overall circuit gain. At the same time, the cross-coupling capacitor is used to neutralize the Miller effect, and the negative feedback is introduced to further improve the circuit stability. Measurements of the PA show a 3dB-bandwith of the output power from 18GHz to 40GHz. The maximum output power is 17.8dBm at 1dB-compression-point (P1dB) and 18.9dBm in saturation. Togeher with the peak gain of 20 dB high power added efficiencies (PAEs) of 10^% in saturation are achieved.