Thinning Satellite Communication Antenna Arrays for Dual Band Operation

Abstract

In this paper a design method is proposed to construct a dual-band operation antenna array, interleaving two arrays, operating at Ku and Ka-band frequencies, on the same real estate. Sharing the same antenna aperture is required to utilize a limited real estate for multiple tasks. First, each array configuration is examined, to achieve optimal initial guess to the thinning algorithms. Triangular lattice is applied for both arrays and overlapping elements are shifted along major axes to allow interleaving of both arrays. Circular aperture is used for the larger Ku array. To analyze the configuration performance, reference arrays are constructed, with rectangular aperture and rectangular lattice. Moreover, genetic algorithm is used to further thinning the Ku array and maintaining a required property of the application. All the analysis is taken considering a scan range of $35^{\mathrm {o}} \bullet 65^{\mathrm {o}}$, to achieve a design that is applicable for satellite communication purposes. The optimal Ku array directivity after thinning at scan angle $\theta =50^{\mathrm {o}}$ is 32.53 dBi (1 dB decrease relative to reference array), using only 74% of the reference arrays elements (rectangular aperture and rectangular lattice). Side lobes level (SLL) remained at -22.19 dB (SLL requirement is -22 dB). The results for the requested scan range shows no grating-lobes in radiation patterns, and satisfactory results comparing to the reference arrays.