?
Range Distance Requirements for Large Antenna Measurements for Square Aperture With Uniform Field Distribution
Frequency dependences of the field for constant angle
of observation measured by different probes at different distances
are discussed.We consider the case of the square aperture antenna
with the uniform field distribution. The analysis is based on timedomain
physical optics method of field calculation. We show and
explain the effect of sidelobe reduction when a big square probe is
placed at a finite distance from square aperture antenna. Errors
of the sidelobe levels of the antenna radiation pattern (ARP) in the
cases of different sizes of the probe placed at different distances
are shown. We show an optimal probe size and an optimal measurement
distance between antennas. We also show and explain
the effect of a large distortion of the ARP first zero, measured by
the big probe at the finite distance.