Ku Band SiGe Power Amplifier With High Output Power and SWR Robustness Up to 120 °C

This paper presents a highly compact Ku band 130nm SiGe power amplifier (PA) in a double balanced architecture. A highly compact low-loss 4 to 1 combiner is associated with a cascode topology to provide a power combination up to 1W and a high resilience to the standing wave ratio (SWR) from 2:1 to 4:1. A high thermal stability up to 120°C is ensured by an advanced configuration of transistors. A choices innovative set on the cascode stage design and layout improves the control of the impact ionization and selfheating. A driver stage allows the circuit to achieve over 20 dB of linear gain. At 30°C, 18 GHz and a supply voltage ( $\text{V}_{\mathrm {SUPPLY}}$ ) of 4.2V, this power amplifier achieves a measured saturated power ( $\text{P}_{\mathrm {sat}}$ ) of 30 dBm for an output power at the 1dB compression point (OCP $_{\mathrm {1dB}}$ ) of 28.8 dBm, a maximum power added efficiency (PAE) of 23.5% and a linear gain of 21.4 dB. The gain difference across 2:1 SWR phase variations is only 0.8 dB. The active area of the die chip is only 1.13 mm ² .