A 16.5–28 GHz 0.18- $\mu$ m BiCMOS Power Amplifier With Flat $19.4 \pm 1.2$ dBm Output Pow

A broadband fully integrated power amplifier (PA) with 3 dB bandwidth from 16.5 to 28 GHz was designed using a 0.18 μm SiGe BiCMOS process. The PA consists of a drive amplifier and two parallel main amplifiers. Lumped-element Wilkinson power divider and combiner are especially used to combine the main amplifiers as well as to provide suppression for the harmonics through their inherent low-pass filtering characteristic. The PA exhibits measured gain of more than 34.5 dB and very flat output power of 19.4±1.2 dBm across 16.5-28 GHz, and power added efficiency (PAE) higher than 20% and 17% between 16-24.5 GHz and up to 28 GHz, respectively. Specifically at 24 GHz, it achieves 19.4 dBm output power, 22.3% PAE, and 37.6 dB gain.