Improved Cylindrical Cavity With Symmetric Double Ridges for High-Sensitivity Detection

In this letter, an improved cylindrical cavity for high-sensitivity detection is proposed. The cylindrical cavity is characterized by symmetric double ridges inside. The double-ridged cavity realizes the electric field compression of TE
$_{\mathbf {01}{n}}$
modes by loading two symmetric metal ridges and further greatly improves the detection sensitivity. The parameters of the ridge are optimized and determined by considering the compromise between frequency detection sensitivity, quality factor, and the current fabrication technique. Several fiber monofilaments with diameters of only a dozen micros are separately inserted into the cavity and detected. To illustrate more clearly the advantage of the proposed cavity for the detection of slim materials, the sensitivity per unit of volume (0.32%) is compared and the value is higher than the related research works.