Recently, a new technology process for manufacturing packaged millimeter-wave silicon IMPATT diodes has been introduced [I, 21. Detailed measurement and simulation results for these devices operating in the D-band frequency range are compared here. Results are obtained in rectangular, reduced height waveguide resonators. CW RFoutput power of more than 100 mW at 135 GHz and 50 mW at 150 GHz are reported.