Space-Based Ultra-Wideband Antennas

Past efforts have demonstrated how inflatable parabolic reflectors could be made for space antennas. More recent laboratory studies have shown how a broadband antenna can result by coupling parabolic reflectors to specially designed impedance-matchingsupport arms. We propose to combine the two technologies to create an inflatable space antenna made from the inflatable parabolic reflector and its inflatable support arms. Our goal is a lightweight broadband space-deployable antenna suitable as animpulse radar antenna or a general broadband antenna. Our approach is to draw on design options we have proven in past inflatable-structures programs for decoys, struts, antennas, and membrane supports. We will examine Conical Support and TubularSupport concepts for the arms/feed. Impedance of the various feed components will be matched to that of the antenna to minimize energy loss from the beam, using concepts proven on these past programs to vary the effective surface conductivity andgeometry. An analytical model will be produced so that antenna design parameters can be varied and the resultant effects on gain and mass calculated. The best feed concept will be selected for bench tests to validate the model. Our team has unmatchedexperience in inflatable space structures and antenna design and test.We are developing, in conjunction with Applied EM, a complete antenna. It can therefore be offered as a subsystem to any mission that needs an IRA. However, the antenna is much morethan an IRA. It is a broadband device and therefore capable of working at many different frequencies that might be of interest. Thus it is the first antenna that can be offered as a product applicable to most space projects. Therefore it offers the realpossiblity of mass producing an inexpensive but effective space antenna.