Abstract

A new dual-band electromagnetic band gap (DBEBG) periodic printed structure is presented here. Designing the periodic unit cell within the periodic boundaries is sufficient to determine the EBG or DBEBG. The concept of the dual-band unit cell is based on stacking two different periodic textures with different parameters. The upper band texture considers the top of the lower band surface texture as a deformed back. Thus, a form of interaction between them makes designing each band individually challenging. Therefore, a comprehensive parametric study is required to design a DBEBG that controls the stop bands. A unit cell with a period of 1.8 mm is presented, achieving a 13-24 GHz and 34-44 GHz DBEBG with the proper parameters.
The effect of inserting the printed ridge breaking the periodicity creates propagating modes within the EBG bands, guiding the electromagnetic waves between the upper conductor and the ridge and suppressing them elsewhere, named PRGW provides dual-band, 13-24 and 34-44 GHz. A dual-band ridge with two 90-degree bends is demonstrated with simulated results of 13-22 and 32-42 GHz. Bends affect guide's scattering parameters, influencing signal reflection and transmission. Discontinuities are common in microwave systems, necessitating investigation during design them. The dual-band power divider is designed within the DBEBG structure, providing 16-24 and 32.5-42.5 GHz. Two quadrature hybrid couplers within a DBEBG support a lower band 14-26 GHz, 60% fractional bandwidth at 20 GHz and an upper band 33-41 GHz, 21.6% fractional bandwidth at 37 GHz. They maintain a 90° ±10° phase difference between coupled and through ports, with isolation levels below 10 dB. The dual-band design holds potential for millimeter-wave applications and dual-band filter design.