Self-Biased Ku-Band Circulators

A self-biased Ku-band circulator has been designed and measured. A pre-oriented substituted strontium hexaferrite SrM with a strong anisotropy field and high remanent magnetization was used for the component design. A minimum insertion loss of 0.95 dB with more than 15 dB isolation has been measured. However, a frequency shift of 1.5 GHz has been observed between the simulation and the measurement. Retro-simulation, taking into account the metallization dimensions, led us to believe the anisotropy field and the permittivity considered to be inaccurately evaluated. Nonetheless, these experimental results demonstrate the high potential of hexaferrites for the realization of Ku-band circulators.