EXACT ELECTROMAGNETIC FIELD THEORY FOR BROADBAND H-PLANE WAVEGUIDE JUNCTION CIRCULATORS

<正> This paper analyses the broadband H-plane waveguide junction circulators with the metal step and partial-height ferrite post. Using the field match method, the eigenmodes are given to expand the electromagnetic field in ferrite. The eigenmodes include not only the volume modes in literatures, but also the surface modes derived in this paper. Two sets of modes are used in analysis. The match between junction and waveguides is simplified, using a synthetic method, combining the electromagnetic field theory with the eigenvalue theory of the symmetric network scattering matrix and the transmission line theory. In an 8-mm band, the calculated bandwidth is 19％ with 20-dBisolatioa. Computation and experiments are in good agreement. The calculated results display n=2 Chebyshev response characteristics.