An experimental high isolation ferrite substrate circulator magnetized by trigonally symmetric pole pieces

A distinct enhancement of the traditional circulator in both the isolation and operational bandwidths has been found to be realized by means of a trigonally symmetric magnetic system. Experiments utilizing the field probing scheme which the present author published previously have verified that the proposed magnet system significantly contributes to the simultaneous enhancement of both the bandwidth and the isolation, in that field concentration favoring isolation enhancement is realized, and that tapered field matching is established. The proposed new magnet system has enabled a compact C-band circulator to be implemented with isolation as high as 30 dB or more for a relative bandwidth of 27 percent while holding the insertion loss at less than 0.5 dB.