  The real-time power monitoring of gyrotron is one of the key issues in the
operation of electron cyclotron resonance heating system. The detector can be
used for real-time power monitoring. We analyzed the principle of diode
detection and designed a D-band wideband detector based on Schottky diode in
this paper. The detector includes a waveguide-to-microstrip transition, a
matching circuit, a diode, and a low pass filter. A novel
waveguide-to-microstrip transition was developed based on probe coupling. A
wideband lossy matching circuit was developed based on tapered-line and series
matching resistor. The simulation results show that when the input power is
-30dBm at 140 GHz, the detection sensitivity is about 1600V/W.
