Broadband antennas using a planar ultra-wideband balun

Ultra-wideband antennas can be systematically and simply designed utilizing a new ultra-wideband planar balun, which is a microstrip-to-CPS (coplanar stripline) transition. The new balun has the operating bandwidth of over 40 GHz. With the proposed balun as an antenna feed, design examples of three types of antennas are presented. Comparisons of simulated and measured results demonstrate validity of the design procedure.