Emerging array antenna technologies at JPL

JPL/NASA's Earth remote sensing and deep-space exploration programs have been placing emphasis on their spacecraft's high-gain and large-aperture antennas. At the same time, however, low mass and small stowage volume are demanded in order to reduce payload weight and reduce shroud size and thus reduce launch cost. To meet these goals, the concept of an inflatable parabolic reflector was introduced about two decades ago. However, the full implementation of this concept is still hampered by the inability to achieve the required surface accuracy. Even with the technologies of rigidizable membrane, stretchable aluminum, UV-cured polymer, and hardenable gel, it is believed that it will be difficult to maintain the desired parabolic surface accuracy for the duration of long space missions To mitigate the effect of curvature, a new class of planar array technology is being developed. It is believed that it will be significantly easier to maintain the required surface tolerance of a flat structure, such as the planar array, than a curved structure such as a parabola. In addition, a planar array offers the possibility of wide-angle beam scanning which cannot be easily achieved by a parabolic reflector. At JPL, three planar array antenna technologies are being developed. These are microstrip reflectarray[1,2,3], inflatable planar array[4,5], and foldable frame-supported thin-membrane array[4]. They are separately discussed in the following paragraphs.