Novel stacked‐defected ground structures for ultra‐wideband low loss balun designs

Abstract

AbstractA novel stacked‐defected ground structure (SDGS) for ultra‐wideband and low‐loss balun design was developed. The balun implements an inductive compensation method on a multilayer liquid crystal polymer (LCP) substrate to control phase and amplitude imbalances. Based on a 15‐dB input return loss and 0.5 dB insertion loss criterions, the balun has a measured bandwidth from 70 MHz to more than 2.1 GHz, a measured amplitude and phase imbalances are less than 0.5 dB and 5°, respectively. With a compact size of 36 mm × 51 mm × 0.23 mm, the 0.5 dB loss‐balun achieves both the largest bandwidth ratio (30:1 ratio) and the most improved imbalances reported to date on a printed circuit board.