Inflatable Coplanar Patch Antenna Array for Spaceborne Applications

This paper presents the design of an inflatable coplanar patch antenna array as to increase the Technology readiness level (TRL) to 3 for application into future space-based radio astronomy antennas. The objective of this antenna is to communicate at 2.4 GHz with Earth when placed on a rocket. The advantage of using an inflatable antenna at its final destination in space is the ability to pack it in a small volume and unpack it in space. Earlier inflatable antennas have been designed as reflector antennas, thereby using the inflatable antenna surface as a passive reflective surface using metallized film. Previous research related to active inflatable antennas has focussed on the feasibility of using active antenna elements on an inflatable antenna for an ultra low frequency radio astronomy application. In this work, two designs are made on thin film and their electrical performance and structure is tested. These designs consist of a 2 by 4 patch antenna array, which are fed via coplanar waveguide connected to a micro coaxial connectors which have the advantage on being small and lightweight and lockable as to increase the retention force. The second design also contains a feeding network including a CPW Wilkinson divider and T-Junction. These prints were made from gold with a metal thickness of 150 nm on 25 μm thick BoPET film. Measurements and simulations show a double-sided realized gain of 11.8 dBi is achieved, excluding cable losses.