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A 225 GHz Circular Polarization Waveguide Duplexer Based on a Septum Orthomode Transducer Polarizer

2013; IEEE Microwave Theory and Techniques Society; Volume: 3; Issue: 5 Linguagem: Inglês

10.1109/tthz.2013.2264317

2156-3446

Carlos A. Leal‐Sevillano, Ken B. Cooper, Jorge A. Ruiz‐Cruz, José R. Montejo‐Garai, Jesús M. Rebollar,

Electromagnetic Simulation and Numerical Methods

In this paper, we present the modeling and experimental validation of an efficient, compact, and high-isolation waveguide duplexer operating at 225 GHz. While duplexers based on ferrite circulators are key components of many monostatic radar systems, at W-band frequencies and above the performance of waveguide circulators rapidly deteriorates. The design presented here uses a ferrite-free duplexing concept based on transmitting and receiving in orthogonal circular polarizations. The circular polarization is efficiently generated in waveguide using a septum orthomode transducer polarizer, leading to a compact device with a single horn antenna. The complete duplexer is designed using efficient numerical algorithms, resulting in a fabricated device with a measured 10% fractional bandwidth, a return loss better than 20 dB, isolation of 30 dB, and insertion loss below 1 dB.