Novel folding technique for planar ferrite-coupled-line circulators

A novel folding technique for a longitudinally magnetized ferrite-coupled-line (FCL) section is reported in this paper. The results from Ansoft HFSS simulations of a single-folded structure are presented for a 17-GHz folded stripline FCL section and the measurements on the 17-GHz folded stripline three-port FCL circulator confirm the folding concept and demonstrate that nonreciprocal behavior is retained.