A study on the coaxial aperture electromagnetic sensor and its application in material characterization

A full-wave analysis of the aperture fields of a coaxial electromagnetic sensor is presented. The authors use a full-wave formulation of the problem and develop an integral equation to evaluate the aperture fields under various conditions. The effects of a finite-size flange and the presence of higher-order modes are studied. The aperture admittances are evaluated and compared with the corresponding results obtained by G. Roussy et al. (1992). These results are also compared with previous ones obtained under the quasi-static approximation and with measured data. This study is expected to facilitate in situ material characterization in the millimeter-wave frequency range.<>