Theoretical and experimental modeling of longitudinal characteristics of TEM cells

Longitudinal characteristics of transverse electromagnetic (TEM) cells include longitudinal variations of electric field and impedance. These characteristics have only been observed in an in-depth experimental investigation reported by Crawford et al. (1974,1977). A theoretical approach to model these characteristics is presented. Their relations with voltage standing wave ratio (VSWR), loss, terminal load impedance, characteristic impedance, and cell dimensions are reflected in expressions derived. Numerical results agree well with reported experimental data at some frequencies at which full information about the longitudinal variations was obtained with electric field probes. Concepts concerning longitudinal nonuniformity of both field and impedance are proposed and are useful in the evaluation of the longitudinal characteristics of TEM cells in use.<
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