New multi-layer millimetre-wave folded reflectarray antennas for satellite communications

A broadside folded reflectarray antenna consisting of 108 dual-polarization antenna elements, operating at Ka band, is presented in this paper. The unit cell antenna employed is dual-polarised aperture-coupled microstrip patch antenna integrated with via-grid cage around the edge of the unit cell in order to reduce mutual coupling between the neighbouring elements. True-time microstrip delay lines connecting two kinds of polarizations are used to achieve the purpose of polarization conversion and phase compensation. The delay lines are connected with the feeding striplines via a vertical RF transitions. The simulated results show that the gain of this folded reflectarray enable to achieve over 20 dBi across the operating frequency band. The proposed structure of the unit cell makes it possible to integrate controllable phase shifter with the antenna together for electronically beam scanning.