Yang Lin

Date of Award


Level of Access Assigned by Author

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)


Electrical and Computer Engineering


David E. Kotecki

Second Committee Member

Donald M. Hummels

Third Committee Member

Nuri W. Emanetoglu


Voltage-controlled oscillators (VCOs) and phase-locked loops (PLLs) are widely used in modern communication, remote sensing and imaging systems. At present, designing VCOs and PLLs in high-GHz and terahertz (THz) is challenging. Wide- working-range VCOs and PLLs, which are attractive in ultra-wideband (UWB) and multiple-channel communications, can be limited by their architectures.

This dissertation first reviews state-of-the-art VCO and PLL applications and describes challenges in the radio frequency (RF) circuit design and measurements. It then introduces VCO and PLL basics, reports previous work on VCOs and PLLs, as well as explores tradeoffs in high-frequency and wide-working-range VCO and PLL designs. Three methods to improve the VCO and PLL operation frequency as well as their tuning and locking range are proposed. To verify these methods, five VCOs and one PLL were designed in a 130nm SiGe BiCMOS process. These designs either achieve high-GHz or THz frequencies or work over a wide operating range.