Abstract：The dual focus flat cavity (DFFC) is a novel device for shielding effectiveness test. In order to determine the size of dual focus flat cavity (DFFC) in the frequency range 1~18GHz, the resonance characteristics of the elliptical resonator is researched through analytical and numerical methods. It is proved that the height of the cavity which mainly determines the resonant frequencies of TMmr1 and TEmr1 modes is the main factor that affects the transmission coefficient from input port to output port. So, the upper limit of frequency is defined as 80% of the cutoff frequency of TMmr1 mode. Furthermore the newly designed DFFC is manufactured. Finally the Shielding effectiveness test technology involving time domain gate is researched.
[1] Hong Y K, Lee C Y, Jeong C K, et al. Method and apparatus to measure electromagnetic interference shielding efficiency and its shielding characteristics in broadband frequency ranges[J]. Review of Scientific Instruments, 2003, 74(2): 1098-1102. [2] Sarto M S, Tamburrano A. Innovative test method for the shielding effectiveness measurement of conductive thin films in a wide frequency range[J]. IEEE Transactions on Electromagnetic Compatibility, 2006, 48(2): 331-341. [3] Marvin A C, Dawson L, Flintoft I D, et al. A method for the measurement of shielding effectiveness of planar samples requiring no sample edge preparation or contact[J]. IEEE Transactions on Electromagnetic Compatibility, 2009, 51(2): 255-262. [4] Jacobs I S, Bean C P. Fine particles, thin films and exchange anisotropy[J]. in Magnetism, 1963, 3: 271- 350. [5] Catrysse J. Shielding effectiveness of flat samples and conductive gaskets: new measuring cell for the frequency range 1-18GHz[C]//IEEE International Symposium on Electromagnetic Compatibility, Detroit, MI, 2008: 1-6. [6] Kwon J H, Choi H D, Choi J I, et al. Development of apparatus for measuring electromagnetic shielding effectiveness at GHz frequency band[C]//IEEE International Symposium on Electromagnetic Comp- atibility, Honolulu, HI, 2007: 1-4. [7] Dvurechenskaya N, Zielinski R J. Advantages and disadvantages of the free-space arch method used for investigation of shielding materials at low gigahertz frequencies[C]//10th International Symposium on Electromagnetic Compatibility, York, 2011: 790-795. [8] Nishikata A, Tosaka T, Fukunaga K, et al. Shielding effectiveness measurement using dual-focus flat cavity at microwave frequency range[J]. Transactions of the Institute of Electronics Information & Com- munication Engineers B, 2008, 91: 88-94. [9] Tosaka T, Nishikata A, Fukunaga K, et al. Measurement of shielding effectiveness in the microwave frequency range using a dual focus flat cavity[C]//IEEE International Symposium on Elec- tromagnetic Compatibility, Honolulu, HI, 2007: 1-4. [10] Tosaka T, Nishiakta A, Fukunaga K, et al. Shielding effectiveness measurement for anisotropic materials using DFFC[C]//Proceedings of ISAP, Niigata, Japan, 2007: 93-96. [11] Tosaka T, Nishiakta A, Fukunaga K, et al. Method for estimating sheet resistance of thin shielding sheets using DFFC[C]//Proceedings of GA of URSI, CD Proceedings (BP10), Chicago, 2008. [12] Tosaka T, Nishiakta A, Fukunaga K, et al. Method for sheet resistance estimation up to 33GHz using DFFC[C]//International Symposium on Electromagnetic Compatibility-EMC Europe, Athens, 2009: 1-4. [13] Tosaka T, Nishiakta A, Fukunaga K, et al. Evaluation of system for estimating sheet resistance using DFFC[C]//URSI International Symposium on Electro- magnetic Theory, Berlin, 2010: 81-84. [14] Kretzschmar J G. Wave propagation in hollow conducting elliptical waveguides[J]. IEEE Transactions on Microwave Theory and Techniques, 1970, 18(9): 547-554.
2015, Vol. 30 
