Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Chemical and Biological Engineering


Chemical Engineering

First Advisor

Nigel F Reuel


Contact-free sensing systems have gained interest in recent years for various medical, environmental, agricultural, petrochemical, and food safety applications. The major limitation associated with the existing approaches, is the need to include a local power source, which affects the price, durability, and safety of the system. Herein, we present a novel, low-cost, flexible, and passive resonant sensors for contact-less measurement of physical, chemical, and biological parameters. The primary method used for fabricating resonant sensors was designing Archimedean spirals with varying dimensions adjusted based on the application, and chemical etching copper-coated polyimide masked with the desired senor design. The significant feature of this development was the elimination of on-board power and contact-less data acquisition, for which an external reader antenna was designed and 3D-printed. To do so, a two-port vector network analyzer was used to excite the external reader to generate a local electromagnetic field for sensor interrogation. The principle of the sensor response was based on variations in the dielectric properties (e.g. relative permittivity and conductivity) of the sensor surrounding environment, which led to changes in the resonant frequency and peak-to-peak amplitude of the sensor scattering parameter signal. The sensor response was automatically recorded and then further analyzed via custom MATLAB scripts.


Copyright Owner

Sadaf Charkhabi



File Format


File Size

216 pages

Available for download on Saturday, August 28, 2021