A 170 GHz GaN-Based Frequency Doubler With Over 500 mW Output Power

This paper reports a 170 GHz frequency doubler with high output power based on GaN planar Schottky barrier diode (SBD) technology. The frequency doubler realizes satisfactory power handling capabilities by utilizing a GaN SBD chip featuring twelve anodes. To improve doubler performance, the circuits included are designed in suspended microstrip that has low attenuation at the expected terahertz frequencies, and a suspended microstrip-to-waveguide transition with bias circuit employing a compact microstrip resonating cell is developed. For demonstration, a prototype of the frequency doubler is fabricated and tested in pulsed mode, delivering over 430 mW from 167 to 173 GHz with a conversion efficiency of 12.5%–15%. An output power of 520 mW and 508 mW is obtained at 169 GHz and 170 GHz respectively.