Wideband Quarter Wave Transformer Based on Defected Ground and Split Ring Resonator Structures

This article examines a wideband impedance transformer based on a split ring resonator and defected ground structures. The transformer was designed as a 4section binomial one and it provides a transformation from 50 Ω to 100 Ω. Reversed Z” shaped defects are formed on the ground plane of the design in order to increase the bandwidth. The design has been simulated using a 3D electromagnetic simulator which utilizes finite integration technique. Three distinct resonances are exhibited at specific frequency spots as proofs of the concept of impedance matching. Theoretical and simulated results are in a good agreement with each other and the proposed design might be tailored in many microwave circuits and antenna applications.