[IEEE 2016 IEEE/ACES International Conference on Wireless Information Technology and Systems (ICWITS) and Applied Computational Electromagnetics (ACES) - Honolulu, HI, USA (2016.3.13-2016.3.18)] 2016 IEEE/ACES International Conference on Wireless Information Technology and Systems (ICWITS) and Applied Computational Electromagnetics (ACES) - Design of a cavity backed 15:1 bandwidth two arm spiral helix antenna