An electromagnetic analysis of a coaxial cavity cell

An electromagnetic analysis of a coaxially-excited coaxial cavity is presented. Equations are derived for the fields inside the cavity, the currents on the conducting walls, and for the cavity admittance. An accurate approximate method for calculating the losses in the cavity walls and the effect on the admittance is also reported. Experimental results are presented which demonstrate the accuracy of the theory. This work represents the first step in the development of a technique to employ the coaxially excited coaxial cavity as a cell for the measurement of the permittivity of homogeneous materials over a wide frequency range.