The non reciprocal effect of such devices as microstrip and coplanar isolators can be based on the field displacement phenomenon induced by a magnetized ferrite material. The structure under study is made from a ferrite thin-film deposited on a alumina substrate. A non symmetrical coplanar line is put on the ferrite film and the absorber is made from either a graphite film or a Tantalum Nitride film or a copper slab. In order to work in millimeter wave range the barium ferrite was selected. Moreover, the size of the component could be less than the circulator one. The small size and simple shape are the principal advantages of a coplanar isolator structure.
1. Capraro, S., T. Rouiller, M. Le Berre, J. P. Chatelon, B. Bayard, D. Barbier, and J. J. Rousseau, "Feasability of a self biased coplanar isolator with barium ferrite films," IEEE Transactions on Components and Packaging Technologie, Vol. 3, No. 3, 411-415, September 2007. doi:10.1109/TCAPT.2007.898747
2. Capraro, S., T. Rouiller, M. Le Berre, J. P. Chatelon, B. Bayard, D. Barbier, and J. J. Rousseau, "Exploration of the integration of passive coplanar isolator based on thin magnetic films," Microwave and Optical Technology Letters, Vol. 46, No. 5, 435-437, September 2005. doi:10.1002/mop.21009
3. Zuo, X. and C. Vittoria, "Self-biased circulator/isolator at millimeter wavelengths using magnetically oriented polycrystalline strontium M-type hexaferrite ," IEEE Trans. Microwave Theory Tech., Vol. 39, No. 5, 3160-3162, September 2003.
4. Pardavi-Horvath, M., "Microwave applications of soft ferrites," Journal of Magnetism and Magnetic Materials, Vol. 215–216, 171-183, June 2000. doi:10.1016/S0304-8853(00)00106-2
5. Courtois, L. and M. De Vecchis, "A new class of nonreciprocal components using slotlines," IEEE Trans. Microwave Theory Tech., 511-516, June 1975. doi:10.1109/TMTT.1975.1128612
6. Hines, M. E., "Reciprocal and nonreciprocal modes of propagation in ferrite stripline and microstrip devices," IEEE Trans. Microwave Theory Tech., Vol. 19, No. 5, 442-451, 1971. doi:10.1109/TMTT.1971.1127545
7. Wen, C. P., "Coplanar waveguide: A surface strip transmission line suitable for nonreciprocal gyromagnetic device application," IEEE Trans. Microwave Theory Tech., Vol. 17, No. 12, 1087-1090, 1969. doi:10.1109/TMTT.1969.1127105
8. Hanna, V. F. and D. Thebault, "Theoretical and experiment investigation of asymmetric coplanar waveguides," IEEE Trans. Microwave Theory Tech., Vol. 32, No. 12, 1649-1651, December 1984. doi:10.1109/TMTT.1984.1132906
9. Heinrich, W., "Quasi-TEM description of MMIC coplanar lines including conductor-loss effects," IEEE Trans. Microwave Theory Tech., Vol. 41, No. 1, 45-52, January . doi:10.1109/22.210228
10. Stancil, D., Theory of Magnetostatic Waves, 101-107, Springer, 1993.
11. Tsutsumi, M., K. Kikui, and T. Ueda, "Characteristics of slot line with yttrium iron garnet substrate and its application," Proceedings of APMC 2001, 1219-1221, 2001.
12. Tao, H., Landy, C. Bingham, X. Zhong, R. Averitt, and W. Padilla, "A metamaterial absorber for tera-hertz regime design, fabrication and characterization," Optical Society of America, Vol. 16, No. 10, 12, May 2008.