AFSS superstrate integrated microstrip antennas- a progressive study

This paper presents an overview of the recent developments for Adaptive Frequency Selective Surfaces (AFSS) integrated patch antennas. The limitations of the FSS based microstrip antennas mainly, narrow impedance and gain bandwidth have been overcome by using adaptive FSS (AFSS). This is because the integration of the lumped-element devices in the FSS has several advantages like radiation bandwidth enlargement, controlling the resonance frequency, high directivity etc. The study includes various FSS structures loaded with different electronic components/devices such as capacitors, inductors, varactors as well as PIN diodes etc. The simulation results shown reveal the effect of these devices on the transmission and reflection characteristics as well as overall performances of the antennas. The frequency tuning over 500-700 MHz around 2.5 GHz has been reported along with a total antenna area reduction by 55%.