Experiment of a hybrid-type implementation of an adaptive array under directional constraint

The VHF 2-channel adaptive antenna system was constructed by means of the output minimization under directional constraint, and its performance was evaluated. In the field experiment, the preservation of the desired signal and elimination of the interference wave were confirmed. The system adopts a hybrid-type implementation of the analog processing part and digital processing part. The correlation between the input and output is calculated by the analog portion and the remaining computation is made by the digital portion. The time variation of the desired signal and the interference component, the frequency spectra of the output and the antenna directivity were measured in the laboratory. When the desired signal and the interference wave have the common frequency band, the interference wave can be suppressed sufficiently by this system if their incoming directions differ. The signal-to-interference ratio was above 30 dB. In the field experiment, we obtained 20 dB.