A Lumped Model of the Rod Antenna Setup Adopted for Military and Automotive Testing

A lumped model of the rod antenna measurement setup adopted in the automotive (CISPR 25 ALSE test method) and military testing (MIL-STD 461 RE102 test method) is derived here. The model permits to get immediate physical insight into the different behavior observed when the counterpoise of the rod antenna is connected to the shielded enclosure or floated, as recently suggested by some authors for the purpose of improving measurement reproducibility. A new test configuration is also investigated here for the same purpose. The model is valid up to a few megahertz, where the lumped element approximation is effective. Several experimental results confirming the lumped model predictions and extending the investigated frequency range up to 30 MHz are offered.