Traceable calibration of a horizontally polarised reference antenna with omnidirectional pattern at VHF frequencies for ILS field strength validation

[摘要] We present a traceable calibration of a specially designed horizontallypolarised reference antenna with an omnidirectional pattern in the E-planefor the frequency range between 105 MHz and 120 MHz. This antenna is used asa validation tool for absolute field strength measurements at the localizertransmitter of an instrument landing system (ILS) at airports and iscarried by a helicopter. We investigate whether we can treat it as adipole-like antenna in the calibration setup despite its disk-shape body. Wealso investigate the suitability of an anechoic chamber for antennacalibration though it was not designed for that purpose. The measurementsare based on scattering parameters (S-parameters) which we apply in the3-antenna-method (TAM or 3-AM) to obtain the antenna gain and the antenna factor,respectively. An uncertainty budget for the antenna gain calibration isderived. We also report on the first practical application of the calibratedreference antenna.

[学科分类] 电子、光学、磁材料