@conference {14_EuCAP_Leal-SevillanoRuiz-CruzMontejo-GaraiEtAl_NovelDual-BandSingle, title = {Novel Dual-Band Single Circular Polarization Antenna Feeding Network for Satellite Communications}, booktitle = {Proc. 2014 European Conference on Antennas and Propagation (EuCap)}, year = {2014}, month = {Apr.}, pages = {1-5}, abstract = {In this paper a novel dual-band single circular polarization antenna feeding network for satellite communications is presented. The novel antenna feed chain1 is composed of two elements or subsystems, namely a diplexer and a bi-phase polarizer. In comparison with the classic topology based on an orthomode transducer and a dual-band polarizer, the proposed feed chain presents several advantages, such as compactness, modular design of the different components, broadband operation and versatility in the subsystems interconnection. The design procedure of this new antenna feed configuration is explained. Different examples of antenna feeding networks at 20/30 GHz are presented. It is pointed out the excellent results obtained in terms of isolation and axial ratio.}, keywords = {antenna, Circular polarization, diplexer, dual-band, K/Ka band, multibeam, orthomode transducer, polarizer, satellite communications, waveguide}, author = {C A Leal-Sevillano and J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M} } @article {13_IEEETHz_Leal-SevillanoCooperRuiz-CruzEtAl_225GHzCircularPolDuplexer, title = {A 225 GHz Circular Polarization Waveguide Duplexer Based on a Septum Orthomode Transducer Polarizer}, journal = {IEEE Transactions on Terahertz Science and Technology}, volume = {3}, number = {5}, year = {2013}, month = {Sep.}, pages = {574-583}, abstract = {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.}, keywords = {Circular polarization, duplexer, orthomode transducer, terahertz}, issn = {2156-342X}, doi = {10.1109/TTHZ.2013.2264317}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=6525512}, author = {C A Leal-Sevillano and Cooper, K B and J A Ruiz-Cruz and Montejo-Garai, J R and Rebollar, J M} }