Optimisation of radiation efficiency for a transverse ground-plane slot in boxed-stripline

A stripline-excited cavity-backed transverse slot radiator is analysed using a moment method. The analysis solves a pair of simultaneous integral equations that describe the magnetic fields in the vicinity of the slot, in terms of the tangential electric fields of the upper and lower surfaces of the slot, and the Green´s functions for the neighbouring regions. A comprehensive dyadic Green´s function is developed to model the feedline structure for the practical case where the central conducting strip is located entirely under the radiating slot. Computed results for resonant length and resonant resistance are analysed and compared with measured results, while the computational efficiency of the analytical model is established by investigating its convergence properties. An examination of scattering as a function of the parameters, slot offset and strip impedance shows how the efficiency of the coupling between the feedline and the radiating slot can be optimised