Radio-Frequency and Millimeter-Wave Integrated Circuits

Radio-frequency integrated circuits have made a profound impact on the lives of people around the world through  the introduction of low-cost wireless communication and internet. As radio-frequency communication proliferates,  new systems and circuits are require to operate over multiple standards and bands.

As RF bands become crowded, millimeter-wave bands offer new spectrum that promises much higher data rates. Millimeter-wave circuits and systems realized on silicon integrated circuits could open new markets for high-speed wireless communication, imaging, and radar sensors. Our group invents new circuits to push the performance of integrated circuits operating at RF and millimeter-wave bands. These inventions are demonstrated  using low-cost silicon integrated circuit processes.

A Low-power, Q-band Modulator

An 12-bit, Q-band Direct-conversion Modulator with <2.5% EVM at 48 Mbps

A 34% PAE, 18 dBm Power Amplifier at 45 GHz

Millimeter-wave Constructive Wave Amplifiers

First introduced at International Solid-State Circuits Conference (ISSCC) 2009, the cascaded constructive-wave amplifier combines features of traveling-wave and cascaded amplifiers for millimeter-wave application.  The proposed technique amplifiers forward traveling waves while attenuating backward traveling waves through a cascade of stages that share a single transmission line.

Wireline Communication Circuits and Systems

Wireline communication is a rapidly evolving part of the modern network infrastructure. High-speed data must be transmitted between chips using electrical or optical communication over wires to reach the lowest power requirements. We are inventing new circuits and systems to communicate at high data rates and requiring low-power consumption through the integration of optical components into silicon integrated circuit processes.

High-speed Baseband Circuits and Systems

As demands on communication networks increase, the interface between the digital and analog world becomes severely constrained.  We are looking a broad range of circuit solutions to meet these challenges. Our research is studying how to use CMOS scaling to improve the speed of mixed-signal interfaces and also how to use optical techniques - in collaboration with other research groups - to leap past CMOS scaling for future the high-speed sampling.

The first 100 GHz bandwidth amplifier implemented in a Silicon/Silicon-Germanium process

A 25-Gb/s Fully-integrated Optical Transceiver implemented in Silicon-on-insulator (SOI) CMOS

Cascaded Constructive Wave Amplification

Prof. Buckwalter explains the principle of the constructive wave amplifier. This new amplifier invention has been recognized as a US patent.

A low-power 40-Gb/s Transmitter capable of 3 Vpp single-ended swing and Receiver operating at under 9 mW.

A 9-bit 2-GS/s Master-Slave Track and Hold Amplifier

Demonstrating the need for optical sampling for high-speeds and high-resolution quantization.