Uncertainties in the Estimation of the Gain of a Standard Gain Horn in the Frequency Range of 90 GHz to 140 GHz

This paper examines the validity of employing the Naval Research Laboratory's (NRL) on-axis gain calibration curves as a standard reference, as specified in the commercial Standard Gain Horn (SGH) antenna datasheets, for the frequency range of 90 GHz to 140 GHz for antenna gain measurements. We present a comprehensive analysis of the on-axis gain calibration curve characteristics and the dimensions of the SGH antenna by employing three different dimensional measurement techniques and quantifying the discrepancies in comparison to the on-axis calibration curve found in datasheets. Additionally, we demonstrate that inaccuracies in the dimensional data provided in the commercial SGH antenna datasheet can lead to a gain deviation of ±1 dB from the anticipated gain. We validate the on-axis gain curves obtained from simulation by conducting measurements in a spherical anechoic chamber.