Abstract: An F-band broadband power detector is developed based on a commercial detector diode and quartz substrate. The three-dimensional electromagnetic model of the detector diode is built for fully consideration of parasitic effects of diode passive structure under high-frequency conditions. The quartz-based probe transition, direct current and radio frequency grounding circuits involved in the power detector are designed respectively. Based on optimized results, a prototype is fabricated, assembled and measured. In the 90 GHz~140 GHz frequency range covered by the full F-band, the measured voltage sensitivity is about 700 mV/mW with about -15 dBm drive power, while the peak sensitivity is 1 100 mV/mW at 123 GHz, the typical tangential sensitivity is about -30 dBm. Measured results agree well with simulated performances.