Experimental Ka-band array elements for ATM-Sat terminal antenna

A novel aperture-coupled square patch is presented with an asymmetrical-stripline feed. The design has been carried out as an array element as per terminal antenna specifications for the ATM-Sat project. The designs have been simulated and optimized using a commercially available moment-method solver. The effect of ground thickness, dielectric and conductor loss as well as the presence of bonding glue has been considered in the analysis. Impedance bandwidths of nearly 9 and 17% have been achieved at 20 and 30 GHz respectively. Radiation patterns with infinite ground assumption show broad patterns suitable for wide-scan arrays. Backlobe is found to be absent in this analysis. The 30 GHz design has been simulated with a finite ground plane of dimension 0.8λ using a commercial FEM-based solver. This shows good cross-polarization and backlobes which are expected to improve in the practical case due to a larger ground plane. The result shows the effectiveness of the stripline ground-plane in suppressing back radiation, which is an important feature for improving the electromagnetic compatibility with electronic circuit boards in a multilayer structure. The proposed element seems to be suitable for wide-angle scanning array application