Reduced-height Waveguide Y-Junction Circulator Based on Two Asymmetrical Gyromagnetic Posts

In this paper, a patent pending reduced-height waveguide Y-junction circulator structure based on two asymmetrical gyromagnetic posts is presented. This new reduced-height topology is of high interest for implementation in waveguide microwave systems requiring size and weight reduction. Furthermore, the proposed structure is not based on any metal post impedance transformer used in most waveguide Y-junction circulator topologies found in the literature. This particularity results in a simpler design increasing ease of manufacturing. In addition, this arrangement is well suited for implementation in the emerging multilayer printed circuit board (PCB) air-filled substrate integrate waveguide (AFSIW) technology expected to enable the integration of high-performance systems on substrate. The design of the proposed circulator is detailed with the introduction of a theoretical model. A quarter-height WR51 demonstrator operating in the 17.3 to 21.2 GHz frequency range, used for downlink Ka-band satellite communication applications, is designed and fabricated for experimental validation. In the operational frequency range, the prototype achieves a return loss, transmission loss and isolation better than 20 dB, 0.2 dB and 24 dB, respectively.