Loss Reduction in Reflectarray Designs Using Sub-Wavelength Coupled-Resonant Elements

A novel design approach is proposed for designing high performance reflectarrays using low-cost, lossy substrates. Using sub-wavelength coupled-resonant elements, in particular sub-wavelength loops, one can dramatically reduce losses in reflectarrays and not incur significant gain drop due to the use of the lossy, low-cost substrate. It is further shown that the sub-wavelength loop achieves sufficient phase variation in a single layer design with a modest requirement in etching tolerance, making the loop superior to both the single and double-layer sub-wavelength patch elements.