Narrowband Frequency-Selective Surface on 3D-Printed Substrate for X-Band Applications

This paper presents a miniaturized frequency-selective surface (FSS) for X-band application with narrowband resonance. Three-dimensional (3D) printing technology is utilized for realizing the proposed design, and the substrate is printed using stereolithography. The design comprises a convoluted square-loop structure with cross dipoles printed on the 3D printed substrate of 1.6 mm thickness. The proposed design resonates at 12 GHz with stopband characteristics and achieves a loss of 58 dB. The FSS offers 7.7% fractional bandwidth in the 20 dB range with a shielding effectiveness of 36 dB. Moreover, the proposed design can achieve stable transmission characteristics for transverse electric (TE) and transverse magnetic (TM) modes for various angles of incidence up to 60°. The size of the unit cell is 5 mm × 5 mm, and an array of 20 × 20 unit cells are fabricated for the testing. The effects of the dielectric constant and loss tangent are also studied in detail.