The efficiency of use of the parabolic reflector of a single offset reflector compact antenna test range (CATR) is affected largely by the illumination provided by the range feed and the reflector edge treatment. Thus, when these factors are taken together it is commonly found that the realized quiet zone (QZ) diameter is typically as little as 30% of the diameter of the reflector for the commonly encountered case of a single offset CATR. Furthermore, single offset CATR performance is known to degrade as the wavelength of the illuminating fields becomes more comparable with the physical dimensions of the reflector because the physical optics (PO) assumption needed for collimation of the reflected field becomes less effective. Different reflector edge treatments such as rolled or serrated edges are commonly employed to taper the intensity of the reflected fields at the reflector aperture boundary, seeking to minimize the level of diffracted fields in the quiet-zone (QZ). Such strategies mean that at higher frequencies the transverse dimensions of the QZ are unnecessarily reduced thereby decreasing the spatial efficiency of the CATR and limiting the effective bandwidth of the antenna test system. In this paper we report preliminary results that begin to investigate the alternative strategy for controlling the signal illuminating the CATR reflector by utilising a shaped beam feed antenna. Building on our previously reported work of efficient CATR computational electromagnetic simulation, we report the use of an array feed whose excitation is optimized to achieve maximum QZ size. We illustrate the concept by employing the technique with a sector-shaped, reflector single offset CATR having no edge treatment and then using the same reflector with an edge treatment and by examining the impact that this has on the amplitude taper and the amplitude and phase peak-to-peak ripple.
[1]
C. G. Parini,et al.
Computational electromagnetic modelling of compact antenna test range quiet zone probing: A comparison of simulation techniques
,
2016,
2016 10th European Conference on Antennas and Propagation (EuCAP).
[2]
M. Philippakis,et al.
Compact antenna range performance evaluation using simulated pattern measurements
,
1996
.
[3]
A W Rudge,et al.
Mathematical Modelling of the Radiation Fields from Microwave Primary-Feed Antennas
,
1977,
1977 7th European Microwave Conference.
[4]
C. G. Parini,et al.
CATR Quiet Zone Modelling and the Prediction of “ Measured ” Radiation Pattern Errors : Comparison using a Variety of Electromagnetic Simulation Methods
,
2015
.
[5]
Janse van Rensburg,et al.
Theory and Practice of Modern Antenna Range Measurements
,
2014
.
[6]
Graeme L. James,et al.
Geometrical Theory of Diffraction for Electromagnetic Waves
,
1980
.
[7]
Trevor S. Bird.
Improved solution for mode coupling in different-sized circular apertures and its application
,
1996
.
[8]
Clive Parini,et al.
Mutual coupling in a finite planar array of rectangular apertures
,
1987
.