The problem of electromagnetic waves radiation into a space outside a perfectly conducting sphere through a narrow slot, cut in an end-wall of a semi-infinite rectangular waveguide, excited by a fundamental wave of H10 type is solved using a rigorous self-consistent formulation. The starting point for the analysis is the one-dimensional integral equation for the equivalent magnetic current in the slot, obtained by using the effective thickness of the slot. The asymptotic solution of the equation was found by the generalized method of induced magnetomotive forces (MMF). The physical adequacy of the constructed mathematical model to the real physical process is confirmed by experimental data. Influence of the sphere radius upon energy characteristics of the slot radiator was investigated numerically. It was shown that at any frequency of waveguide single-mode range, the radiation coefficient of a spherical antenna can be made close to one by choosing the slot length, the sphere radius and the waveguide height. Conditions for correct application of infinite screen approximation for spherical scatterers with sufficiently large radii are formulated.
2. Reznikov, G. B., Antennas of Flying Vehicles, Soviet Radio, Moscow, 1967 (in Russian).
3. Schantz, H., "Nanoantennas: A concept for efficient electrically small UWB devices," IEEE International Conference ICU, 264-268, Sept. 2005.
4. Ramo, S., J. R. Whinnery, and T. Van Duzer, Fields and Waves n Communication Electronics, 3rd Ed., Wiley, 1994.
5. Karr, P. R., "Radiation properties of spherical antennas as a function of the location of the driving force," J. Res. Nat. Bur. Stand., Vol. 46, 422-436, 1951.
doi:10.6028/jres.046.045
6. Mushiake, Y. and R. E. Webster, "Radiation characteristics with power gain for slots on a sphere," IRE Trans. Antennas and Propagat., Vol. 5, 47-55, 1957.
doi:10.1109/TAP.1957.1144465
7. Liepa, V. V. and T. B. A. Senior, "Modification to the scattering behavior of a sphere by reactive loading," Proc. IEEE, 1004-1011, 1965.
doi:10.1109/PROC.1965.4080
8. Lin, , C. C. and K. M. Chen, "Improved radiation from a spherical antenna by overdense plasma coating," IEEE Trans. Antennas and Propagat., Vol. 17, 675-678, 1969.
doi:10.1109/TAP.1969.1139506
9. Lin, C. C. and K. M. Chen, "Radiation from a spherical antenna covered by a layer of lossy hot plasma," Proc. IEEE, Vol. 118, 36-42, 1971.
10. Towaij, S. J. and M. A. K. Hamid, "Diffraction by a multilayered dielectric-coated sphere with an azimuthal slot," Proc. IEEE, Vol. 119, 1209-1214, 1971.
11. Penkin, Y. M., "Conductivity of impedance spherical slot antenna," Radio Physics and Radio Astronomy, Vol. 3, 341-347, 1998 (in Russian).
12. Jang, S. O. and J. E. Hyo, "Radiation of a hertzian dipole in a slotted conducting sphere," IEEE Trans. Antennas and Propagat., Vol. 57, 3847-3851, 2009.
doi:10.1109/TAP.2009.2026065
13. Penkin, Y. M. and V. A. Katrich, "Excitation of Electromagnetic Waves in the Volumes with Coordinate Boundaries,", Fact, Kharkov, 2003 (in Russian).
14. Gavris, B., "Plane wave diffraction by a sphere loaded with a circular slot," Radiophys. Quant. Electron., Vol. 35, 126-130, 1992.
doi:10.1007/BF01038894
15. Rothwell, E. and M. Cloud, "Natural frequencies of a conducting sphere with a circular aperture," Journal of Electromagnetic Waves and Applications, Vol. 13, No. 6, 729-755, 1999.
doi:10.1163/156939399X01302
16. Leung, K. W., "Theory and experiment of a rectangular slot on a sphere," IEEE Trans. Microwave Theory Tech., Vol. 46, 2117-2123, 1998.
doi:10.1109/22.739292
17. Kwok, W. L., "Rectangular and zonal slots on a sphere with a backing shell: Theory and experiment," IEEE Trans. Antennas and Propagat., Vol. 51, 1434-1442, 2003.
doi:10.1109/TAP.2003.813639
18. Penkin, Y. M. and R. I. Klimovich, "Characteristic and reciprocal conductivities of slit radiators on a perfectly conducting sphere," Telecommunications and Radio Engineering, Vol. 55, No. 9, 9-16, 2001.
19. Nesterenko, M. V., V. A. Katrich, Y. M. Penkin, and S. L. Berdnik, "Analytical and Hybrid Methods in Theory of Slot-Hole Coupling of Electrodynamic Volumes,", Springer Science+Business Media, New York, 2008.
20. Garb, H. L., I. B. Levinson, and P. Sh. Fredberg, "Effect of wall thickness in slot problems of electrodynamics," Radio Eng. Electron Phys., Vol. 13, 1888-1896, 1968 (in Russian).
21. Nesterenko, M. V. and V. A. Katrich, "The asymptotic solution of an integral equation for magnetic current in a problem of waveguides coupling through narrow slots," Progress In Electromagnetics Research, Vol. 57, 101-129, 2006.
doi:10.2528/PIER05060902
22. Nesterenko, M. V., V. A. Katrich, Y. M. Penkin, V. M. Dakhov, and S. L. Berdnik, Thin Impedance Vibrators. Theory and Applications, Springer Science+Business Media, New York, 2011.
doi:10.1007/978-1-4419-7850-9
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