ESA measurements using the Hybrid Fibre-Optic Reflection Measurement System

Since the introduction of the wheeler cap method to measure the radiation efficiency of an electrically small antenna (ESA), there have been several techniques presented in literature that have either enhanced on the method or provided an alternative technique. This paper presents measurements of the radiation efficiency of an electrically small monopole using the hybrid fibre-optic RF reflection measurement system (HRS) integrated into the wheeler cap. The HRS isolates the ESA from the measurement system. The ESA´s reflection coefficient can then be measured with the isolated ESA inside the wheeler cap and in freespace to determine its efficiency. The HRS has also been demonstrated in a far-field measurement range to measure the isolated far-field radiation pattern of the ESA.