Characteristics of a thin-wire circular loop antenna in a parallel-plate waveguide

An electrically thin-wire circular loop antenna located inside a parallel-plate waveguide is analyzed by a truncated complex Fourier expansion method. A set of Pocklington type integral equations is derived and transformed using the method of moments into a set of simultaneous linear equations in terms of the unknown current coefficients. The input current and impedance are computed as a function of loop size, plate-to-plate and loop-to-plate separations, for several lumped impedance loads. The interaction of loop and parallel-plate guide resonant modes is discussed. Finally, the effect of the parallel plates on near fields in the vicinity of the loop is computed in terms of shielding effectiveness. This is useful in assessing the loop EMI interference with neighboring elements in an array structure