Integrated Back-to-Back Barrier-N-N+ Varactor Diode Tripler Using a Split-waveguide Block

The back-to-back barrier-N-N+ (bbBNN) varactor is a nonlinear device being developed for frequency multiplier applications above 100 GHz. Its symmetrical C-V characteristic, low series resistance and suitability to planarization make it ideal choice for high frequency, low power, odd harmonic generation. In this paper, development of an integrated planar multiplier device and its performance as a 220 GHz tripler is presented. A new split-waveguide block design has been used to provide the proper embedding impedances to the device. The performance over 200-240 GHz has been measured and the integrated bbBNN device is shown to provide as much as 734 microwatts output power. A flange-to-flange tripling efficiency of 7% has been obtained. This is believed to be the highest conversion efficiency yet reported for all planar tripler at this frequency. The performance is expected to be improved further with minor changes to the device and circuit parameters.