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Radiation of a Hertzian dipole placed within a cylindrical cavity with narrow slots is investigated. Narrow axial and transverse slots are considered. Scattered fields are expanded in terms of eigenfunctions and boundary conditions are enforced to obtain a set of simultaneous equations. Computations are performed to check the validity of the formulation.
Hirokazu KAWABATA Hiroshi TANPO Yoshio KOBAYASHI
A rigorous analysis for a TM010 mode cylindrical cavity with insertion holes is presented on the basis of the Ritz-Galerkin method to realize accurate measurements of the complex permittivity of liquid. The effects of sample insertion holes, a dielectric tube, and air-gaps between a dielectric tube and sample insertion holes are taken into account in this analysis. The validity of this method is verified from measured results of some kinds of liquid.
Rangsan WONGSAN Chuwong PHONGCHAROENPANICH Monai KRAIRIKSH Jun-ichi TAKADA
This paper presents the analysis of the impedance characteristics of a sectoral cylindrical cavity-backed axial slot antenna excited by a probe. The integral equations are derived based on boundary conditions of the proposed structure and they are expressed in terms of dyadic Green functions and unknown current densities. The dyadic Green functions are obtained by using the eigenfunction expansion method together with application of scattering superposition techniques. The unknown current densities are solved by the Method of Moments. The input impedance is subsequently determined from the unknown electric current density at the probe. Numerical results of input impedance and return loss are demonstrated as functions of frequency for various parameters such as cavity length, cavity radius ratio, slot location in φ direction, slot length and probe length. Calculated results are validated by the measurements. At the operating frequency, it is found that the result is sufficiently accurate. The results from this study are very useful for the design of a sectoral cylindrical cavity-backed axial slot array antenna excited by a probe with omnidirectional beam radiation.