SIW based modified slotted array antenna with circular polarization for X, Ku and K band communications

This paper presents a novel approach to the design of substrate integrated waveguide (SIW) based slotted array antennas. It is proposed that wideband characteristics can be achieved when SIW is fed by a combination of longitudinal and transverse slots. 45° inclination of the transverse slots excites the orthogonal components of E-field to phase quadrature leading to circular polarization. To validate the design, a compact antenna of volume 29.72 × 37.92 × 1.6 mm
³
is fabricated on a 1.6 mm thick FR4 substrate. Simulated and measured results show good return loss under 10 dB from 10 GHz-27 GHz covering X, Ku and K bands. The 3-dB axial ratio bandwidth (ARBW) is 1.90% (10.38 GHz-10.58 GHz) in the X band, 10% (17 GHz-18.7 GHz) in the Ku band, and 1.11% (19.58 GHz-19.8 GHz) in the K band. It is also observed from the far field patterns that the main lobe can be discretely scanned from +22.5° to +67.5° in the X band. Given the specifications, the antenna is suitable for deployment in aircraft and satellite communications.