Sub-wavelength air cavities in uniaxial metamaterials

Reducing the size of device components, e.g. waveguides and resonant cavities, beyond the diffraction limit is a means to an end. Here we demonstrate the condition required to have air cavities within a uniaxial metamaterial clad waveguide. Our work reveals that air cavity sizes much smaller than the operating wavelength (D2h/λ3=6.7e-4) are achievable under specific conditions of cladding material parameters, which could have great impact on miniaturization of electromagnetic devices.