High Gain, Wide Band and Wide Scanning Substrate Integrated Waveguide based U-Slot Phased Array Antenna for X-band

The aim of this research work is to investigate a probable Substrate Integrated Waveguide (SIW) based U-Slot Microstrip Patch Antenna (MPA), operating in X-band to provide a high gain, wide scan coverage and wideband especially for radar applications. The combination of U-Slot and thick substrate leads to wider bandwidth operation. It also leads to a form factor reduction tending to broaden the beam which helps to reduce the scan loss. The SIW structure is carefully designed with an optimal form factor having fabricable via diameter to via spacing ratio. SIW structure formed from PTH vias around the element emulates the metallic cavity effect, which helps to mitigate the surface wave propagation in the substrate controlling the mutual coupling (MC) in turn. This paper presents a thorough and systematic design process enunciated with simulation results generated using ANSYS HFSS software. A 16-element U-Slot SIW MPA Array is designed and examined in this paper. The array shows a bandwidth > 15%, peak gain
$\sim \mathbf{17.7}\mathbf{dB}$
and scan volume
$> \pm \mathbf{45}^{\circ}$
with worst level of MC < -18dB over the operating frequency band. These features make it suitable for the phased array antenna (PAA) developments.