Extraction algorithm of reflection coefficient for antenna VSWR meter based on directional coupler and integrated amplitude phase detector

For the reflection coefficient testing, and then the VSWR or Return Loss of antenna, a simple testing circuit based on a directional couplers and an integrated detection chip AD8302 is introduced, which is respectively used for the sampling of forwards incident and backwards reflected wave and then the amplitude & phase detections. But due to the limited directionality of directional coupler and the input ports mismatch of integrated detector, it is difficult to sample a pure forwards incident and backwards reflected wave. To bypass the sampling difficult of a pure incident and reflected wave, an extraction algorithm of reflection coefficient is proposed. The experimental test result shows that the reflection coefficient testing circuit with the extraction algorithm is effective, a portable antenna VSWR meter based on it can be used for the maintenance of base-station antenna & cable system.