Authors: Daniel Martinez-de-Rioja, Eduardo Martinez-de-Rioja, Jose A. Encinar, Yolanda Rodriguez-Vaqueiro, Antonio Pino
Source: FERMAT, Volume 37, Communication 8, Jan.-Feb., 2020
Abstract: Direct-to-home (DTH) applications usually require a radiation pattern with a given footprint on the surface of the Earth and impose stringent cross-polarization requirements in the form of crosspolar discrimination (XPD) or crosspolar isolation in a given bandwidth. This paper describes a multifrequency broadband optimization procedure and performance results of a very large spaceborne reflectarray for DTH application in a 10% bandwidth. The proposed design methodology is based on the generalized intersection approach and the use of a multi-resonant unit cell with multiple degrees of freedom (DoF). The procedure is divided into three stages to facilitate convergence towards a broadband performance. First, a initial narrowband design at central frequency is obtain. Then, a broadband optimization including XPD requirements is carried out with a limited number of DoF. Finally, more DoF are included in the last stage optimization to obtain a broadband reflectarray with improved cross-polarization performance.
Index Terms: reflectarrays, optimization, space communications, shaped-beam, generalized intersection approach
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Advanced Reflectarray Antennas for Multispot Coverages in Ka Band