Layout of MOS Varactor with Improved Quality Factor for Cross-Coupled Differential Voltage-Controlled Oscillator Applications

In this study, we designed an MOS varactor for application in the differential voltage-controlled oscillator (VCO). To improve quality factor of varactor, proposed a symmetric layout technique with reduced parasitic components. Compared typical layout, metal line interconnection varactors that is inevitable cross-coupled VCO was minimized to reduce resistance. addition, line, overall size also compared one. verify feasibility structure, and were using 180 nm RFCMOS process. measured improved by approximately 32% at operating frequency 5.0 GHz. Additionally, successfully verified capacitance induced lossy silicon substrate structure.