Design of a broadband, dual-band, large reflectarray using multi open loop elements

Abstract

Microstrip reflectarray technology is rapidly becoming an attractive alternative to the more traditional parabolic reflector and phased array antennas due to its various advantages such as low profile, significant simplification of feed systems in the case of multi-polarization/band antenna systems and low loss as discussed in [1,2]. The goal of this paper is designing a high gain, large, dual-band reflectarray as a satellite portable terminal at Ku-band. The conventional reflectors were satisfactorily used to fulfil all the electrical requirements for this particular application. However, application of such reflectors in a portable scenario is a complicated task due to mechanical considerations. The reflectarray antenna designed in this paper can overcome this shortcoming. This reflectarray was etched onto 9 substrate panels of 40 cm × 40 cm each, which were finally assembled to realize the larger 120 cm × 120 cm reflectarray. Therefore, the reflectarray assembly is superior to its conventional reflector counterpart from portability point of view. The antenna is designed for two frequency bands: 11.4 GHz – 12.8 GHz for receive and 13.7 GHz– 14.5 GHz for transmit, both with linear but orthogonal polarizations. An optimization method as introduced in [3] was used in this paper to design the reflectarray elements for the receive band due to the large bandwidth requirement at this band. For the transmit band elements, double square loop elements [4] were used and conventional design rules for a reflectarray were applied to adjust the dimensions of the cell elements.