Synthesis of hecken-tapered microstrip to parallel-strip baluns for UHF frequency band

Summary form only given, as follows. Microstrip to parallel-strip transitions are frequently used for feeding balanced antenna structures, such as dipoles and printed spiral antennas. In this paper, we propose an analytical method to compute the gradual taper using a Hecken approach to minimize the return losses. The proposed method is verified experimentally with the aid of three transitions including matching capabilities with different ratios, suitable for spiral antenna structures in the ranges from 450 MHz to 2 GHz.