A Canonical Scatterer for Transient ScatteringRange Calibration

We describe here a simple process for calibrating a transient scattering range. The process uses a paraboloidal scatterer to transform an axially incident plane wave into a spherical wave. Since the magnitude of the scattered field is known analytically, one can simply calibrate a measurement system. In order to calculate the scattered field, we use a stereographic projection that has previously been called the reflector transform. This technique provides three advantages over traditional calibration with a sphere. First, it is potentially more accurate, since the scattering characteristics of a paraboloid are independent of frequency. There is no need to convert the measured time domain data to the frequency domain in order to deconvolve the characteristics of the scattere~ the entire process takes place in the time domain. Second, this technique is simpler to implement. Finally, this technique is appropriate for certain anechoic chambers built of two-wire and four-wire transmission lines, where the incident field is not quite uniform.