30-GHz CMOS VOLTAGE-CONTROLLED OSCILLATOR USING DRAIN-GATE COUPLED TRANSFORMER TO MINIMIZE THE INFLUENCE OF PARASITIC COMPONENTS

Abstract

In this study, we propose a magnetically coupled drain-gate technique for mm-wave CMOS voltage-controlled oscillator (VCO) applications. To implement the proposed technique, we use a transmission line transformer. Using the proposed technique, it was possible to easily isolate the gate bias of the transistor from the drain bias of the transistor. The gate bias can then be independent of the DC bias of the drain. Accordingly, the frequency can be tuned using the gate bias, whereas the typical VCO obtains the tuning range of the operating frequency using an additional varactor. Consequently, the number of required devices for the proposed VCO decreases and, hence, the chip size is reduced compared to that of the typical VCO. To verify the feasibility of the proposed structure, we designed the VCO using 110 nm RFCMOS technology. From the measured results, we successfully obtained the required tuning range and reduced chip size of the proposed VCO. (C) 2015 Wiley Periodicals, Inc.