A Tripler to 220 GHz Using a Back-to-Back Barrier-N-N+ Varactor DiodeThe 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, the performance of a 220 GHz tripler using integrated planar bbBNN devices is presented.