Frequency-selective surfaces for GPS and DCS1800 mobile communication. 1. Quad-layer and single-layer FSS design

In the paper, frequency selective surfaces (FSS) composed of quad-layer FSS with staggered tuning are designed, to allow signals to pass through at the frequency range of the global positioning system (GPS) cum DCS1800 mobile communications operation, while rejecting signals at the higher frequencies. The FSS is analysed by visualising the transformation of the admittance locus on the Smith chart, on subsequent additions of material layers to the multilayer stack-up. In addition, a single-layer FSS with convoluted loop elements (with interelement spacing of 6.08 cm) is designed to yield a similar band-pass response at 1.575 GHz (wavelength lambda=19.05 cm). This relatively close spacing is achieved by convoluting the conventional 1lambda square-loop element at its four corners. The convoluted segment provides a short-circuit response when the segment length is lambda/4 long. This provides a reflection to the electromagnetic energy at the selected band-stop frequency range. The performance of the quad-layer and single-layer FSS are compared