Low Cost Polarization Insensitive L band FSS Absorber Based on Screen Printing Technique

In this paper, a single-layer radar absorber (RA) design, simulation, and fabrication method based on the screen printing approach i.e resistive ink printed on FR-4 are presented. The proposed prototype has an absorption of more than 90% from 1.05 GHz to 2.14 GHz covering L band. The design is polarization insensitive and stable for oblique electromagnetic wave incidence up to 30 degree for both TE and TM polarization. The result of equivalent circuit model serves as confirmation for full wave simulation result. The fabricated prototype shows measured reflection coefficient below -10 dB from 1.05 GHz to 3 GHz (fractional bandwidth of 96%) with the thickness and periodicity of only 0.070 lambda(L) and 0.076 lambda(L) respectively. To understand the differences between the simulation and measurement results, further simulations with the variation of ink thickness and airgap have been performed. Based on these simulations, the RA with modified parameters (ink thickness of 0.02 mm and air gap of 22.5 mm) has a reflection coefficient below -10dB from 1.1 GHz to 2.74 GHz. The profile of the RA is only 0.086 lambda(L) with periodicity of 0.076 lambda(L). Wide range of applications may be possible due to the structure's lightness and ease of fabrication.