One approach to take for small apertures in solid sheets is to reverse the model. That is model the equivalent dipole, you will have far fewer elements and no meshing issues. Due to the duality between E and H known as Babinet's priciple, this is vaild method.
Check out slide 8 on this link: http://www-ece2.engr.ucf.edu/~tomwu/course/eel6492/notes00/emc9.pdf and pages 50 - 54 on this one: Example 5 is just what I mean. http://faculty.uml.edu/aakyurtlu/16.571/Aperture%20Antennas.pdf (these were the first to show up on Google that showed the points I wanted to make, another search might reveal more information) cheers, Colin.. From: [email protected] [mailto:[email protected]] Sent: Wednesday, July 16, 2003 11:23 AM To: [email protected]; [email protected] Subject: RE: apertures I thought a slot is driven with a potential across the closest sides. Radiation occurs due to current at the far ends. Like two short dipoles spaced a distance (1/2 wavelength with a resonant slot) apart. So at horizontal slot has the E-field vertical and the H-field horizontal. The polarization is vertical for a horizontal slot. I have fooled around with NEC simulations but the mesh that represents the sheet becomes huge and cumbersome when the grid size is kept small (like 1/16 wavelength). I have had some success using the automatic ground plane generation feature and sticking several planes together. Dave From: C N [mailto:[email protected]] Sent: Thursday, July 10, 2003 8:29 PM To: [email protected] Subject: RE: apertures I usually have a problem with these equations. They give no reference to the angle at which the wave is impinging upon the sheet. The way slots work is to put amaximum differential between the longest sides. If the impinging wave puts a circulating current laterally across the slot, the slot will radiate at a maximum. If the impinging wave puts a circulating current longitudinally along the slot, the slot will radiate at a minimum. It's just that there's a lot of other characteristics which define how a slot radiates. Or are we assuming that everything is perfectly lined up for maximum performance? Regards, Doug McKean _________________________________________________________________ STOP MORE SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail 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: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
