EFFECTS OF SELF-HEATING ON PLANAR HETEROSTRUCTURE BARRIER VARACTOR DIODES

The conversion efficiency for planar Al0.7GaAs/ GaAs heterostructure b arrier varactor triplers is shown to be reduced from a theoretical eff iciency of 10% to 3% due to self-heating. The reduction is in accordan ce with measurements on planar Al0.7GaAs/GaAs heterostructure barrier varactor (HBV) triplers to 261 GHz at room temperature and with low te mperature tripler measurements to 255 GHz. The delivered maximum outpu t power at 261 GHz is 2.0 mW, Future HBV designs should carefully cons ider and reduce the device thermal resistance and parasitic series res istance. Optimization of the RF circuit for a 10-mu m diameter device yielded a delivered output power of 3.6 mW (2.5% conversion efficiency ) at 234 GHz.