Ferrite Isolator based on Dual Non-Reciprocal Mode Converting in Rectangular Waveguide

Passive millimeter components play an important role in all future communication systems. Among the most significant devices are isolators, which are considered as essential protection elements in high power applications. It prevents the RF signal from reflecting to the source, and provide the required protection. It depends mainly on the non-reciprocity to allow the power flow in one direction only. In this work, we have designed an isolator based on the non-reciprocal mode conversion in the mm-wave band. This isolator is realized using rectangular waveguide loaded with horizontal ferrite slab in one path. As a result the wave maintain dominant mode operation in one direction, while the mode is converted to the higher order one on the other direction. Afterwards, the second order mode is collected and terminated to a load to protect the source and realize isolation. The proposed design is modeled and simulated to show the objective performance in the operating bandwidth 27-32 GHz. The proposed waveguide isolator achieved an insertion loss below 0.5 dB with an isolation level above 15 dB over the operating bandwidth.