Building an anechoic chamber involves a substantial investment both financially and in physical space. Hence, there is much interest in trying to reduce the required investment while still maintaining adequate performance. The performance of an anechoic chamber depends on the type, size, and array configuration of the absorber elements as well as the geometry of the screened room on which the inner surfaces are covered with RF absorbers. If the room geometry is designed such that an electromagnetic ray from the transmitter will only reach the receiver antenna after a few reflections, the wave energy may be sufficiently damped after a few bounces off the absorbing walls and ceiling. Hence, lower cost RF absorbers can be used to make the anechoic chamber design more economical. In this paper, a variant of beam-tracing technique is used for modeling of anechoic chamber to study the normalized site attenuation (NSA) performance of the anechoic chamber. This allows the chamber performance to be predicted prior to the actual construction. The ma jor advantage of beam-tracing over ray tracing is the path loss information at multiple receiver locations can be determined simultaneously as opposed to running a ray tracing simulation for each receiver location one at a time. As a result, the computing time is greatly reduced. This feature is particularly useful in calculating the field strength at different heights of the receiving antenna in EMC site calibration procedure. The efficient modeling tool has given rise to the successful design and construction of an asymmetrical shape anechoic chamber that supports various measurement needs including EMC tests at the Multimedia University, Malaysia.
Chin Hui Teh,
"Modeling of Anechoic Chamber Using a Beam-Tracing Technique," ,
Vol. 49, 23-38, 2004. doi:10.2528/PIER04020601
1. Garn, H., E. Zink, and R. Kremser, "Problems with radiated emission testing at 3 m distance according to CISPR 11 and CISPR 22," Proceedings of the 1993 IEEE EMC Symposium, 216-221, 1993.
2. Hansen D., D. Ristau, and P. Lilienkamp, "Correcting OATS antenna factors for small fully anechoic chambers," IEEE International Symposium on EMC, 219-223, 2000.
3. Holloway, C. L., R. R. DeLyser, R. F. German, P. McKenna, and M. Kanda, "Comparison of electromagnetic absorber used in anechoic and semi-anechoic chambers for emission and immunity testing of digital devices," IEEE Transactions on EMC, Vol. 39, No. 1, 33-47, 1997.
4. Yang, C. F., B. C. Wu, and C. J. Ko, "A ray-tracing method for modelling indoor wave propagation and penetration," IEEE Transactions on Antennas and Propagation, Vol. 46, No. 6, 907-919, 1998. doi:10.1109/8.686780
5. Kimpe, M., H. Leib, O. Maquelin, and T. H. Szymanski, "Fast computational techniques for indoor radio channel estimation," Computing in Science & Engineering, Vol. 1, No. 1, 31-41, 1999. doi:10.1109/5992.743620
6. Chen, S. H. and S. K. Jeng, "An SBR/Image approach for radio wave propagation in indoor environments with metallic furniture," IEEE Transactions on Antennas and Propagation, Vol. 45, No. 1, 98-106, 1997. doi:10.1109/8.554246
7. Fortune, S., "Efficient algorithms for prediction of indoor radio propagation," 48th IEEE Vehicular Technology Conference, Vol. 1, 572-576, 1998.
8. Teh, C. H. and H. T. Chuah, "An improved image-based propagation model for indoor and outdoor communication channels," Journal of Electromagnetic Waves and Applications, Vol. 17, No. 1, 31-50, 2003. doi:10.1163/156939303766975335
9. Foley, J. D., A. V. Dam, S. K. Feiner, and J. F. Hughes, Computer Graphics: Principles and Practice, 2nd ed., Addison-Wesley, New York, 1996.
10. Murta, A., "A generic polygon clipping algorithm," Avail- able online at http://www.cs.man.ac.uk/aig/staff/alan/software/ index.html, No. 4, 1999.
11. Holloway, C. L. and E. F. Kuester, "Modeling semi-anechoic electromagnetic measurement chambers," IEEE Transactions on EMC, Vol. 38, No. 1, 79-84, 1996.
12. Fante, R. L. and M. T. McCormack, "Reflection properties of the salisbury screen," IEEE Transactions on Antennas & Propagation, Vol. 36, No. 10, 1443-1454, 1988. doi:10.1109/8.8632
13. Kuester, E. F. and C. L. Holloway, "Improved low-frequency performance of pyramidal-cone absorbers for application in semi- anechoic chambers," 1989 IEEE International Symposium on EMC, 394-398, 1989.
14. Janaswamy, R., "Oblique scattering from lossy periodic surfaces with application to anechoic chamber absorbers," IEEE Transac- tions on Antennas & Propagation, Vol. 40, 162-169, 1992. doi:10.1109/8.127400
15. Chung, B. K. and H. T. Chuah, "Modeling of RF absorber for application in the design of anechoic chamber," Progress in Electromagnetics Research, Vol. 43, 273-285, 2003.