Two Antenna Arrays For Remote Sensing Applications

This paper presents two array designs as feeds for parabolic reflector antennas for satellite remote sensing applications. The designs are 4x4 in dimensions and fit within the surface area of one side of a CubeSat. Both arrays are dual-frequency and dual-polarization and are designed on different substrates. The frequencies of interest are 14 GHz and 35 GHz, and the polarizations are vertical and horizontal (or 0 degrees and 90 degrees). One array is designed solely on a Roger RO4003C material, while the other is designed on the RO4003C for the antennas layer and on an RT/Duroid 6010 for the feeding network. The designs are multi-layer and different challenges are being met. For integration purpose, the feed layers must be placed on the same substrates, which in turn require the elimination of any overlapping as well as increased spacing between adjacent lines. Symmetry for the feeds is ensured by using corporate feed networks as the array size (4x4) results in acceptable losses. Parametrization of the feed provided the flexibility to adjust element spacing and achieve a fully nested design where the 35 GHz array lies inside the empty space of a 2x2, 14 GHz sub-array. Also, adequate space for the integration of surface mounted amplifiers directly on the feed network layer is provided. The proposed array occupies only 8.7 cm x 7.2 cm and has similar radiation patterns at both frequencies and polarizations with an excellent front-to-back ratio.