This paper reports design and development of an innovative compact Stepped Truncated-Circular Waveguide Branching Ortho-Mode Transducer (STCWB-OMT) operating at 4.5-4.8 GHz for horizontal and vertical polarizations. STCWB-OMT is derived by introducing branch waveguide via coupling slot on a stepped truncated-circular waveguide. This configuration possesses inbuilt rectangular-to-circular transition; therefore it does not require any additional square-to-circular transition to combine it with horn antenna. The challenge in the design incorporated is to obtain a mechanically compact design with low mass while compliant with the specified electrical performances; since this device is developed for space-borne application. Achieved return losses at both direct and coupled ports are >17 dB, insertion losses <0.08 dB for both polarizations, isolation is <-60 dB and cross-polarization discrimination >40 dB with the OMT length = 1.98λ atcenter frequency and weight = 250 gm The agreement between measured and computed results provides a validation of the proposed OMT configuration.
2. Tribak , A., A. Mediavilla, A. Casanueva, and K. Cepero, "A dual linear polarization feed antenna system for satellite communications," PIERS Proceedings, 1324-1328, Marrakesh, Morocco, March 20-23, 2011.
3. San-Blas , A. A., F. J. Perez, J. Gil, F. Mira, V. E. Boria, and B. Gimeno, "Full-wave analysis and design of broadband turnstile junctions," Progress In Electromagnetics Research Letters, Vol. 24, 149-158, 2011.
4. Uher, J. , J. Bornemann, and U. Rosenberg, Waveguide Components for Antenna Feed Systems: Theory and CAD, Artech House , Norwood, MA, 1993.
5. Kisuregawa , T., Advanced Technology in Satellite Communication Antennas: Electrical and Mechanical Design, Artech House, Norwood, MA, 1990.
6. Bφifot, A. M., E. Lier, and T. Schaug-Pettersen, "Simple and broadband ortho-mode transducers," IEE Proceedings, Pt.-H, Vol. 157, No. 6, 396-400, 1990.
7. Bathker, D. A., "A stepped mode transducer using homogeneous waveguides," IEEE Trans. Microwave Theory and Techniques, Vol. 15, No. 2, 128-130, 1967.
doi:10.1109/TMTT.1967.1126392
8. Stuchly, S., "Wide-band rectangular to circular waveguide mode and impedance transformer," IEEE Trans. Microwave Theory and Techniques, Vol. 13, No. 5, 379-380, 1965.
doi:10.1109/TMTT.1965.1126003
9. Tomiyasu , K., "Four-port scattering matrix for dual-polarized wave transmission and reflection network," IEEE Trans. Microwave Theory and Techniques, Vol. 45, No. 3, 354-358, 1997.
doi:10.1109/22.563333
Submit
