A High-Sensitive Resonant Cavity for Measuring Concentration of Aqueous Solutions

This paper presents a small size cylinder resonant cavity with metal posts embedded for detecting the concentration of aqueous solutions. Compared with a regular cylinder cavity operating in the same mode TM011, the electrical field is more focused on near the tube containing materials under test (MUT), hence, the sensitivity of the cavity is enhanced. Three types of solutions are simulated including glucose, NaCl, and ethanol, varying in concentration from 0 to 5%, the results show that sensitivity is generally improved compared to the regular cavity, with glucose/water from 14 MHz/1% to 46.5 MHz/1%, NaCl/water from 36 MHz/1% to 162.5 MHz/1%, and ethanol/water from 20 MHz/1% to 66 MHz/1%.