Stephen:
I will have to defer to someone who knows what 2D & 3D means, because I don’t. I have also not heard of “maximum” gain. Gain is usually defined along the radial of maximum emission, and despite most antennas being rather obvious which direction that is, the best way is actual measurement. Perhaps you know this already, but you can visualize radiation as the power radiating through an imaginary transparent sphere enclosing the antenna. An antenna will usually create a main lobe and many lesser sidelobes. Identifying the axis of the main lobe can be time intensive, especially if you have a complex antenna structure and no initial idea of how it will perform. The antenna gain will be a combination of antenna efficiency and directional gain (think of how a flashlight may have internal losses and a very narrow emission beamwidth). If you have a high directional gain, the beamwidth may be only a half-degree in both the azimuth and altitude axes, and finding the center of this invisible beam may take hours of scanning (as you have to scan every radial around the sphere). Accurate jigging is a must, followed by methodical investigation. Ed Price WB6WSN Chula Vista, CA USA From: Stephen Whalen [mailto:[email protected]] Sent: Friday, July 01, 2016 12:17 PM To: [email protected] Subject: Re: [PSES] Antenna gain measurement standard Ed, Thanks for the response. I am looking to measure the gain of an antenna in order to calculate EIRP of a product. As far as the 2D vs. 3D, I don't have any values. I was hoping some one who has made measurements using both 2D and 3D would be able to comment how much better 3D is over 2D when considering peak gain. I appreciate your feedback, thanks. Stephen On Friday, July 1, 2016 3:00 PM, Ed Price <[email protected]> wrote: Stephen: There are a number of ways to measure gain, with the basic one being a comparison to a theoretical isotropic radiator (yielding a gain number in dBi). However, the antennas used for EMI and compliance testing are usually used in the near field, where the standard you are testing to defines the acceptable measurement distance and styles of antennas. Thus, there is often a preferred gain measurement technique defined by the standard you are working to. In regard to what you told us, what is 2D & 3D (dimension) gain? And what is peak gain? What standard is defining these terms? Ed Price WB6WSN Chula Vista, CA USA From: Stephen Whalen [mailto:[email protected]] Sent: Friday, July 01, 2016 8:01 AM To: [email protected] Subject: [PSES] Antenna gain measurement standard Greetings, Does anyone know which standard is used for measuring antenna gain? Are 3D antenna gain measurements typically different than 2D with regards to peak gain? If so, what's typical delta, 0.5dB or less? Regards, Stephen - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> On Friday, July 1, 2016 3:00 PM, Ed Price <[email protected]> wrote: Stephen: There are a number of ways to measure gain, with the basic one being a comparison to a theoretical isotropic radiator (yielding a gain number in dBi). However, the antennas used for EMI and compliance testing are usually used in the near field, where the standard you are testing to defines the acceptable measurement distance and styles of antennas. Thus, there is often a preferred gain measurement technique defined by the standard you are working to. In regard to what you told us, what is 2D & 3D (dimension) gain? And what is peak gain? What standard is defining these terms? Ed Price WB6WSN Chula Vista, CA USA From: Stephen Whalen [mailto:[email protected]] Sent: Friday, July 01, 2016 8:01 AM To: [email protected] Subject: [PSES] Antenna gain measurement standard Greetings, Does anyone know which standard is used for measuring antenna gain? Are 3D antenna gain measurements typically different than 2D with regards to peak gain? If so, what's typical delta, 0.5dB or less? Regards, Stephen - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
