Design of UWB Filtering Impedance Transformers and Power Dividers Using Stepped-Impedance Resonators

This study presents a novel design of ultra-wideband (UWB) impedance transformers and power dividers with filtering capabilities. Based on the UWB matching network, are designed, achieved by transforming one port or more transformers. The consist multi-mode stepped-impedance resonator (SIR) defected ground structures (DGSs). SIR is tightly coupled to two ports different levels via unsymmetrical two-sided lines DGSs. In addition, that convert from 50 Ω 100 connected form divider function. 25 Ω an transformer conversion matched in parallel, resulting another Thus, prototype designed their corresponding also fabricated. simulated measured results consistent, demonstrating good features, such as return loss greater than 10 dB insertion less 4.5 passband, capacity out-of-band rejection 20 dB, compact size smaller 1.2λ × 2.1λ (λ wavelength central frequency).