Verification of ultra-broadband calculable dipole antennas & applications

Abstract

Ultra broadband calculable dipole antennas developed by the authors are verified by a slightly modified near-field method, and applications in validating NIM's large metrological open-area test site are provided. Usually, the bandwidth of dipole antennas are quite narrow, and at least three pairs of dipoles with different length are required to cover 30 MHz to 1 GHz. Here we demonstrated that only two pairs of dipoles can cover 10 MHz to 1020 MHz. The accuracy of calculable dipole antennas (CDA) are verified by a slightly modified near-field method by setting up the dipole antennas above a ground plane with quite short separation between transmit and receive antennas. The site insertion loss between a pair of dipoles resonated at 60 MHz agrees with prediction to better than 0.3 dB over 10 MHz to 340 MHz, and better than 0.4 dB over 300 MHz to 1020 MHz for the dipole resonated at 500 MHz. The phase performance of the CDA is also provided. The accuracy of the calculated results for CDAs will not deteriorate even for a very large separation between Tx and Rx, which make CDAs very useful in some applications, e.g., in the validation of open area test site validation (OATS) at 10 m and 20 m separation; both amplitude and phase performance are investigated.