  Radar target simulators (RTS) have recently drawn much attention in research
and commercial development, as they are capable of performing over-the-air
validation tests under laboratory conditions by generating virtual radar echoes
that are perceived as targets by a radar under test (RuT). The estimated angle
of arrival (AoA) of such a virtual target is determined by the physical
position of the particular RTS channel that creates it, which must therefore be
considered when planning the setup. A single channel employs two antennas, one
for the reception and the other for the re-transmission of the incoming radar
signal. The antennas are positioned close together, but still spatially
separated, thus an RTS channel can be considered quasi-monostatic, which causes
non-negligible inaccuracies in the angle simulation. In this paper, the authors
examine the analytical implications of this systemic deficiency on the angle
estimation, which provides support for the design and setup of angle-simulating
RTS systems. The mathematical derivations developed are verified by
measurement.
