To All, We are working toward adding capability to perform Radiated Immunity Free Field Testing (Substitution Method), which is very similar to the IEC 61000-4-3 method. The main differences are the following:
1. We have a 15 position target area for uniformity instead of 16 2. Uniformity for 14 of the points is defined as being within +6/-0 dB with respect to the center position on the bottom row. (position 3 in the diagram below) ******************************************* 11 12 13 14 15 6 7 8 9 10 1 2 3 4 5 ******************************************* - position 3 must be higher in field strength than all 14 remaining points. My Questions: 1. Does anyone have experience with the physical placement of the transmitting antenna and its relative positioning to the target area? I'm looking for things like height between antenna/floor, distance between antenna/target, and antenna angle with respect to horizontal, etc. 2. Is there a need for absorbing material to be placed on the floor between the target and the antenna? If so, what areas, and how much is typically needed? 3. From experience, in general, how achievable is uniformity at low frequency (200MHz - 1GHz) vs. high frequency (1GHz - 4GHz). What hurdles, or obstacles are typical/need to be overcome? 4. Our experience has been that position 3, is generally lower in field strength when compared to other points in the grid. Is this normal? We have tried adjusting the antenna in several different positions/orientations etc. with not much success. Givens: 1. We are using a Double Ridged Wave Guide for 200MHz - 1GHz, and a high gain Horn antenna for 1GHz - 4GHz. 2. We are performing testing in a semi-anechoic chamber. Any help would be greatly appreciated. Regards, Scott Mee EMC Engineer Johnson Controls Inc. PH: 616.394.2565 EMAIL: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
