A Highly Sensitive Sub-THz Slot Disk Resonator for Permittivity Sensing Applications

This letter presents the design and implementation of a highly sensitive slot disk resonator (SDR)-based sensor for permittivity sensing applications at sub-THz frequencies. The sensor utilizes a silicon waveguide (SiWG) on a quartz substrate. The slot within the disk enhances the horizontal electric field, thereby increasing the sensitivity of the sensor by promoting stronger interactions with the material under test (MUT). The measurement results demonstrate the sensitivity of 3.9 GHz/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon _{r}$</tex-math> </inline-formula> for 1-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula>L liquid MUTs.