UC Berkeley

Precision measurements play crucial roles in science, biology, and engineering. In

particular, current trends in high-frequency circuit and system designs put extraordinary

demands on accurate device characterization and modeling. On the other hand, the need

for better point-of-care requires substantial innovation in developing miniaturized sensors

and medical devices that ease the biological analysis without sacrificing the accuracy.

This research presents two advanced measurement techniques for electrical and

biological characterization applications.

In the first part, a novel single-element on-wafer VNA calibration algorithm is

presented dedicated for device characterization at mm-Waves. Conventional calibration

approaches such as thru-reflect-line (TRL) require at least three precisely-machined and

well-characterized standards. The necessity of probe re-positioning leads to significant

measurement errors due to mechanical uncertainty as the measurement frequency

approaches sub-THz. By exploiting on-chip impedance modulation, such an electronic

calibration (E-Cal) algorithm can work with single element without any prior knowledge

of the impedance behavior. This CMOS-based approach opens a new direction in the

field of VNA calibration.

In the second part, the implementation of a dielectric spectroscopy biosensor aiming

for single-cell analysis is presented. Most present day clinical flow cytometers use

fluorescence-activated cell sorting (FACS), which requires bulky optical detection system

as well as complex sample-labeling process, limiting the assay time and the wide-spread

adoption in the point-of-care (POC) setting. To address these issues, this research

presents the design and the implementation of a sensor-on-CMOS spectrometer that

measures the microwave signature of single cell as a potentially label-free analytic tool.

The sensor covers four frequency bands across 6.5 – 30 GHz, offering sub-aF noise

sensitivity at 100-kHz bandwidth. Such performance is enabled with injection-locked

oscillator sensors in interferometry architecture. With microfluidic integration,

experiments on flow cytometry and molecular sensing are demonstrated.