TRL-based measurement of active antennas and other more complex microwave structures

Abstract

A common approach to active antenna design consists of a passive radiator (intrinsic antenna) and an output or input amplifier; all situated on a single microwave board. Such designs show higher radiated power or lower noise floor resulting from low interconnecting line losses. However, since more microwave circuits are connected directly together on a single board, their testing is more difficult. In the given case, this concerns measurement of reflection coefficient of the passive radiator. Methods developed in frames of this work employ the VNA measurement and TRL cahbration, and enable one to evaluate radiator input reflection coefficient in a complete structure without need of any disconnecting or switching. Performed practical measurements show that results can be satisfactorily precise. Generally, the method can be applied for measurement of individual microwave circuits embedded in more complex system PCBs.