ANALYSIS OF A 170-GHZ FREQUENCY DOUBLER WITH AN ARRAY OF PLANAR DIODES

Analysis of a planar diode multiplier from 85-170 GHz is described, Th e doubler uses a waveguide mount with two series pairs of diodes in a balanced structure, Because of the difficulties in conventional scale model measurements, numerical electromagnetic simulation based on the finite element method was chosen for the analysis, using a commercia! program, To optimize the diode design, the de-embedded diode terminal impedance was studied, as well as the power balance between the diodes , The analysis showed that the matching of the diode impedance to that of the waveguide is quite sensitive to the diode substrate thickness, Thicknesses from 25-100 mu m in GaAs were studied as well as 100-mu m -thick quartz, The accuracy of the theoretical analysis was verified b y careful measurements using a slotted line to determine the diode ter minal impedance under large signal pump, for frequencies between 80 an d 90 GHz, Good agreement between the measured and simulated diode term inal impedance was observed, although full agreement requires the addi tion of an empirical loss term, Several options are considered for the source of this loss.