A 8-GHz SiGe HBT VCO Design on a Low Resistive Silicon Substrate Using GSML

A practical layout method called ground shield microstrip lines (GSML) is investigated for the reliable design of high frequency interconnection lines on a low resistive silicon substrate. GSML facilitates the prediction of parasitic networks at the expense of introducing negligible loss. The microwave performance of a GSML line structure is compared to that of a conventional metal line on the same standard silicon substrate (20 Omegamiddotcm). Then, the GSML structure is applied to an 8-GHz SiGe heterojunction bipolar transistor (HBT) voltage-controlled oscillator (VCO) circuit. The GSML method replaces the post layout simulation and reduces iteration time, increasing design efficiency. A fully integrated differential tuning SiGe HBT 8-GHz VCO is designed and tested. The measured phase noise for the VCO is dBc/Hz at 1-MHz offset with an output power of dBm.