Reconfigurable/Tunable Dual Band / Dual Mode Ferrite Composite Right/Left-handed CPW Coupled-Line Coupler

This paper presents the design, modeling and experimental verification of a novel reconfigurable/tunable dual band/dual mode ferrite composite right/left handed CPW coupled-line coupler. The composite right/left handed configuration has been realized by loading coupled CPW transmission lines with series inter-digital capacitors and shunt segment inductors. The coupler performance has been verified using the equivalent circuit model, electromagnetic full wave simulations and experimental measurements. The coupler operates on dual mode in that it has dual bands of operation with two different propagation mechanisms. The first band has only a reciprocal backward coupling whereas the second band has only nonreciprocal through propagation. The non-reciprocity isolation in the second band is better than average of 15 dB. Compared to conventional single band single mode coupled line coupler of length = 0.25 g, the proposed novel dual band dual mode coupler length is almost the same (0.265 g) at 4.5 GHz. Furthermore, the dual mode/dual band coupler can have tunable functionality.