A Novel Multipactor Suppression Circulator Using Transformation Dielectrics

Due to the multipactor discharge breakdown, ferrite circulators have become the most susceptible component losing efficacy in high-power applications such as satellite payload systems. To date, effective suppression method of multipactor without affecting the electrical performance while keeping a high level of stability during in-orbit operation is still a technological challenge. In this article, a novel method based on the composite dielectric transformation is proposed for the considerable improvement of the multipactor breakdown threshold. The transformation medium is composed of dielectric rings of different permittivity, which could realize the uniform field transformation from the susceptibility region of multipactor to the dielectric/vacuum interface without acute change and discontinuity. In addition, the transformation medium is designed to guarantee little perturbance of the electrical performance and great convenience of fabrication and assembly. The experimental results of the S-band circulator using this method demonstrated that while keeping very low insertion loss and isolation level, this method has improved more than 9 dB (≥850%) of multipactor threshold, showing very promising application potentials in antimultipactor designs for the spacecraft payload system.