AUTOMATED SWEPT-ANGLE BISTATIC SCATTERING MEASUREMENTS USING CONTINUOUS WAVE RADAR

The establishment of the IEEE Electromagnetic Modeling Software Committee [12] and the Department of Defense sponsored Electromagnetic Code Consortium [13] indicates the electromagnetics community is interested in validating general electromagnetic modeling software. An important part of this validation is obtaining reliable bistatic scattering measurements on canonical scatterers. This paper describes a simple system well suited for such measurements. The system is capable of measuring bistatic scattering from near backscatter through forward scatter. At X-band frequencies, scattering levels of -50 dBsm in the backscattering region and -20 dBsm near forward scatter can be measured to an accuracy of +/- 1 dB. This fully automated indoor system fixes the target and direction of illumination and sweeps the receive antenna to collect data as a direct function of bistatic angle. A broad band, coherent, continuous wave radar is used to obtain both amplitude and phase of the component of the total field aligned with the receive antenna polarization. Target scattered fields are derived from the phasor subtraction of target and background measurement runs. We consider the system design, calibration procedures, and measurement accuracy. Example measurements on metal cubes and spheres are presented to demonstrate the system performance [6], [9].