Wideband Microwave Photonic Circulator Using Two Asymmetric Partial-Height Triangle Ferrites

Broadband 5G communication requires the operation of nonreciprocal devices in the Ku band. A wideband photonic crystal circulator is implemented by introducing two partial-height triangular Ni-Zn ferrites into the Al₂O₃ ceramic rod-arrays. The asymmetric sizes of the two equilateral triangles paired with self-matching effectively extend the bandwidth of the circulator eight times over that of the symmetric scheme. Numerical simulations demonstrate that the photonic crystal circulator can obtain a bandwidth of 1.00 GHz with an isolation 25.75 dB and an insertion loss 0.381 dB through optimized matched triangle size ratio, suitable for applications in future communication systems.