Hello group This discussion list is worth reading and very helpful. I thought I might put a question that's been bothering me.
I want to measure EM field (H field) originating from GSM base station antenna (distances 5m-100m), using near field probes for magnetic field. They are commonly used for locating EM radiation sources on PCBs or leakage sources. I see a few problems concerning this measurement. 1. These probes are constructed for sources (PCB, enclosure leakage) that are very close to the probe tip. Power density of the source falls rapidly with distance, so the rest of the probe, including connection cable, is placed in the field that is much lower than close to the probe tip. That is not the case in the far field. Is the calibration still valid for the measurements in far field? 2. Also, measurements should be done outside and inside a room. That means lot of reflections. There must be some cable pick-up. Does this usually add more field or not? After all, I think the measurement will not be too accurate, but can provide the order of magnitude at least. I know I would be better off with the isotropic probe with optic link, but right now I am interested in near field probe. I would like some opinions please. Am I right or am I wrong? Am I missing something? Thanks a lot. Antonio Antonio Sarolic Faculty of Electrical Engineering and Computing Dept. of Radiocommunications and Microwave Engineering Unska 3, HR-10000 Zagreb CROATIA tel. +385 1 61 29 789, fax. +385 1 61 29 717 E-mail: [email protected] --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
