Mechanical investigation of a multi-layer reflectarray for Ku-band space antennas

A multi layer sandwich panel of printed reflectarray (RA) is a complex composition of many different materials enabling a required performance with exceptional properties. The major properties of a multilayer RA include the following: the use of array layers of reflective patches forming the flat structure gives the possibility to focus the electromagnetic waves; the use of more than one reflecting layer is widening the RF bandwidth; the possibility of having two different polarisations and two different contours of the beams. ieve the mentioned properties, analytical and experimental investigations have been carried out. A sandwich panel for a three-layer printed reflectarray for dual polarisation with a different coverage in each polarisation has been designed, manufactured and tested. The measured radiation patterns of the RA show that gain requirements are fulfilled in a 10% bandwidth. Thickness and flatness accuracy requirements are also fulfilled. Low dissipative electric losses (0.35 dB) have been achieved, as a result of an appropriate mechanical design and selection of low-loss materials for the RA panel.