High conversion gain broadband frequency doubler design

This paper focuses on the design of frequency doublers operating in the RF and microwave frequency ranges. To reject the fundamental and third harmonic signal over a broadband frequency range, an active balun was employed in the broadband frequency doubler which has resulted in fundamental signal and third harmonics signal rejection better than 12 dB from 12 to 30 GHz input frequency. More than 9.5dBm output power was achieved over the 24-60GHz doubled frequency band for 2dBm input power. The circuit was designed with a 0.15um gate-length InGaAs based on Pseudomorphic High Electron Mobility Transistor (pHEMT) Microwave and Millimeter IC (MMlC) technology.