A 60-GHz Frequency Tripler With Gain and Dynamic-Range Enhancement

In this paper, a single-stage 60-GHz frequency tripler is presented with -1.1 -dB conversion gain in a 0.15-μm pseudomorphic HEMT process. When the input power backs off, unlike most of its counterparts, the conversion gain of the proposed tripler degrades very little. This feature is achieved by adjusting load impedances independently for the first and third harmonic. Besides the enhancement of the third harmonic power, substantial fundamental power is also generated without additional power consumption and is further used to drive an auxiliary diode tripler. The third harmonic power from the original field-effect transistor (FET) and the auxiliary diode tripler are combined with the conversion gain further enhanced, and the power dynamic range is also extended due to the power contributed from the auxiliary tripler. Quantitative analysis for the harmonic loading effect of the FET tripler and the bias selection for the diode tripler are conducted by using the equivalent-circuit models. The theories are verified by computer-aided design simulations and experimental results.