0.3-THz SiGe-Based High-Efficiency Push–Push VCOs With > 1-mW Peak Output Power Employing Common-Mode Impedance Enhancement

We present a novel method of maximizing the output power and efficiency of millimeter-wave and terahertz signal sources, which are based on the push-push topology. In this method, the common-mode impedance of a differential Colpitts oscillator operating in the odd mode is maximized by introducing a fixed-valued capacitor (Cr) at the common-base node. This capacitor is designed to introduce a commo...