A four-layer waveguide structure comprising a dielectric substrate, a metal layer, a left-handed material (LHM) as a guiding layer, and a cladding is investigated as a metal-clad waveguide sensor. Fresnel reflection coefficients are used to study the resonance dips at which the reflectance minimizes. Our calculations show that the proposed structure has a preference over the surface-plasmon resonance structure since it gives a much sharper reflectance dip and can achieve considerable sensitivity improvement. The effects of the LHM permittivity, permeability, and thickness on the reflectance curves is studied
