Fjs. Moreira et al., MINIMIZATION OF THE PLANE-WAVE SCATTERING CONTRIBUTION OF INVERTED-Y STRUT TRIPODS TO THE NOISE TEMPERATURE OF REFLECTOR ANTENNAS, IEEE transactions on antennas and propagation, 44(4), 1996, pp. 492-499
This work is concerned with determining the metallic strut cross secti
on of inverted-Y tripods to minimize the plane-wave scattering contrib
ution to the noise temperature of ground-station reflector antennas an
d radio telescopes. This is accomplished by numerically optimizing the
cross section for minimum ground-noise pickup over the antenna elevat
ion-angle operation range, Advantage is taken of the fact that althoug
h the struts' cross-section perimeter can be comparable to the operati
on wavelength, their electrical lengths are usually long, This allows
the struts' scattering characteristics to be determined by solving sta
ndard two-dimensional field integral equations. This work concentrates
on the top strut of an inverted-Y configuration since it is responsib
le for the dominant ground noise pickup associated with the plane-wave
scattering, Numerical simulations are presented to substantiate this
fact and a simple and convenient broadband closed-form representation
for the minimum-noise top-strut cross section is derived and tested.