Bandwidth-Enhanced Quadrature Power Splitter and Balun Using Metamaterial Transmission Lines

In this paper, the bandwidth-enhanced quadrature power splitter (QPS) and balun using metamaterial (AM transmission lines (M) are presented. They consist of a Wilkinson power divider, a conventional TL, and a well-synthesized MM TL. Since the phase response of the MM TL can be arbitrarily synthesized, the slope of the phase-response curve of the MM TL can be achieved as the same as that of the conventional TL with a specified phase difference, such as 90 degrees or 180 degrees, over a wide frequency range. Two components are designed and implemented at 2 GHz and experimentally demonstrated. The QPS has an output amplitude imbalance of less than 0.9 dB and a phase error of less than +/- 5 degrees from 1.1-3.5 GHz (104% relative bandwidth), while over the frequency range of 1.24-3.58 GHz (97% relative bandwidth), the balan has an output amplitude imbalance of less than 0.7 dB and a phase error of less than +/- 10 degrees.