Multi-channel digital antenna pattern measurement for DF system calibration

The calibration of a broadband, dual-polarized direction finding system requires the measurement of an enormous quantity of accurate antenna pattern data, and the processing of that data into a digital format compatible with the system calibration algorithms. A high-speed multiplexing architecture has been implemented which permits interleaved measurements of 16 independent channels. The particular antenna system under consideration is a multi-element array consisting of four 2 to 18 GHz sinuous antennas. Phase and amplitude response must be measured for both vertical and horizontal polarizations on each output port at 201 frequencies. To fully characterize the antenna, azimuth patterns are measured at 9 different elevation angles. The data is collected in 1.0 degree increments over ±90 degrees, and processed by a proprietary Antenna Measurement System and HP8530 Receiver operating in `Turbo´ mode