Magnitude and phase calibration of microwave sensors

Current network analyzer technology allows both magnitude and phase to be accurately recorded in antenna measurements, raising the possibility of fully characterizing microwave sensors. These calibrated sensors can then take data which may be convolved with arbitrary inputs as well as transformed into the time domain. Such measurements require, however, some standard calibration to measure against: a ''standard phase horn'' so to speak. This paper first extends the definitions of several commonplace antenna parameters and equations to include phase. Given these necessary tools, a number of methods are used to derive a phase calibration and the results are presented. While every method used yields the proper results, only a few are easily applicable to phase measurements. Using these results, a calibration curve is derived for the Lawrence Livermore National Laboratory EMPEROR monocone. Comparison with low-frequency D probes shows the calibration to be accurate to within 1 dB and 5 degrees. EMPEROR is then found to be a nearly perfect, ''flat'' transmitter from 50 Mhz to 18 GHz. This allows it to be used as magnitude and phase calibration range. In concert with an HP 8510 based measurement system, this allows engineers to quickly and accurately measure the complete response ofmore » antennas and other EM systems.« less