VHF/UHF Ultrawideband Tightly Coupled Dipole Array for CubeSats

To date, CubeSat radars and imagers have been limited to operations beyond S-band due to the challenges associated with the design of wideband, compact, low-frequency antennas. Concurrently, the frequencies at VHF/UHF bands can image through clouds and foliage, and are very attractive for ice, water and biomass sensing. There is thus a need to develop wideband antennas that can operate at VHF/UHF bands which are low cost, light-weight, and packable. In this paper, we present a CubeSat deployable Tightly Coupled Dipole Array (TCDA) that achieves VSWR<3 from 80 MHz - 600 MHz, and VSWR<4 from 65 MHz - 600 MHz. While the array itself is 1.2 m in length, 10 cm in width and 1.5 mm in thickness, it can be folded and stowed in a compact volume of 0.40U. We detail the design of the array, demonstrate the folding mechanism, and validate its performance through measurements.