Microwave Transmission Line Based Sensing and Activation Platform in Modern Engineered Energy System
Date of Award
12-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Electrical and Computer Engineering (Holcomb Dept. of)
Committee Chair/Advisor
Hai Xiao
Committee Member
Tao Wei
Committee Member
Lianfeng Zhao
Committee Member
Huijuan Zhao
Abstract
Modern energy systems face growing demands for higher efficiency, reduced emissions, and flexible operation. These needs motivate sensing and control approaches that are non-intrusive, robust, and compatible with industrial environments. Microwave transmission-line structures provide such capabilities by guiding electromagnetic waves along simple conductors to sense material states and deliver localized energy. This dissertation investigates how coaxial transmission lines can be configured to achieve both sensing and activation functions.
The first platform is a stainless-steel-quartz coaxial cable sensor designed for distributed high-temperature measurement. Stainless-steel conductors and a quartz insulator provide mechanical strength and thermal resilience, while CNC-machined and laser-resurfaced girdle reflectors enable time-domain tracking of the temperature-dependent electromagnetic length. A 3D-printed retaining collar secures the connection between the sensor and signal cable. Prototype tests demonstrated measurements up to 600 °C, and sensor performance metrics such as sensitivity and stability were evaluated.
The second platform is a non-contact liquid-level sensor based on a cylindrical coplanar waveguide (CCPW). Conductive paint is sprayed onto a glass cylinder to form the CCPW, and the air-liquid interface is detected from time-domain reflections. Experiments show a 29.8 µm resolution over a 210 mm range within a 500 MHz–4 GHz bandwidth.
The final platform is a coaxial microwave reactor incorporating a limestone–charcoal packed bed. An electromagnetic-thermal model links electric field distribution, power dissipation, heat transfer, and effective permittivity. Experiments validate the model and show how geometric scaling controls power density, hot-spot location, and temperature uniformity.
Collectively, the results demonstrate that microwave transmission lines can be engineered as versatile platforms for integrated sensing and activation in demanding energy systems.
Recommended Citation
Jiao, Xinyu, "Microwave Transmission Line Based Sensing and Activation Platform in Modern Engineered Energy System" (2025). All Dissertations. 4104.
https://open.clemson.edu/all_dissertations/4104
Author ORCID Identifier
0009-0004-4209-169X