Full text loading...
Drawing of periodic array of fractal metallic patch elements with primary and secondary structures highlighted on successive elements: (a) fractal cross-dipole elements with interelement spacing of , (b) fractal square-patch elements with interelement spacing of . In this letter, the fractal element size and interelement spacing are varied to investigate their role on stopband attenuation and position.
Ideal PMM simulations for fractal cross-dipole elements with optimized spacing (solid curve) show two strong stop bands. Ideal simulations for primary and secondary single cross-dipoles (dashed curve and circles) each show a single strong stop band indicating that each stage of the fractal structure causes one stop band.
Comparison of measured (solid curve) and simulated (circles) transmission spectra for fractal cross-dipole elements with optimized interelement spacing of . Measured primary and secondary stop bands have attenuation of 13 and centered at 44 and , respectively. For reference, MDPCs of the same geometry fabricated using a single -thick layer of silver as the metal patch elements exhibited a response that is nearly identical to those fabricated using aluminum (shown here). The PMM model includes the effects of metallic and dielectric loss.
Measured transmission spectrum of design 1 of the fractal square patch (solid curve) agrees well with the model prediction (circles curve) and contains two strong stop bands at the same positions as those in the fractal cross-dipole case. Design 2 of the fractal square patch (dashed curve) demonstrates that the position of one stop band can be changed relative to the other by adjusting the element geometry and interelement spacing.
Article metrics loading...