Optimal Design of NRD Isolator Using Ni-Zn Ferrite Post for Millimeter-Wave Integrated Circuit Applications

This paper proposes an optimal design scheme of NRD isolator based on mosaic optimization concept. Binary harmony search algorithm is employed to optimize the pixel pattern in the design region. To reduce the computational cost, recently developed two-dimensional full vectorial finite element method is extended to be applicable to simulate NRD guide devices with magnetic material. In order to show the usefulness of this approach, NRD isolator with Ni-Zn ferrite post is designed at frequency of 26 GHz. The optimally designed NRD isolator has excellent forward transmission and backward rejection of −0.18 dB and −23 dB, respectively.