LAUSR

Abstract In this paper, we propose a novel dual-band coupler based on circular patch structure perturbed with slits, shorting posts and defected ground structures. It is shown that the proposed perturbations allow size reduction and independent control of the operating bands in terms of their position and power-split ratio between the output ports. To demonstrate the potential of the proposed structure, two dual-band 3-dB couplers operating at 2.4/5.2 and 2.4/5.8 GHz have been designed, fabricated and measured. The couplers are characterized by excellent in-band performance and compact size of only 0.41λg × 0.41λg. Additionally, three couplers operating at 2.4/5.8 GHz with different combinations of coupling coefficients at the two operating bands have been designed and fabricated.