EMI modeling of dielectric plugged waveguide array in the perspective of WAIM

The active admittance of an electronically scanned antenna fluctuates widely with scan angle, particularly at the onset of grating lobe. To stabilise the antenna against such fluctuations, dielectric inserts are plugged inside the array elements. Due to mutual coupling the element pattern of each element changes dynamically at scan. The whole problem is analysed by finding the overall scattering matrix of the entire structure by employing the method of moments and finding thereby the exact aperture field corresponding to every beamshape and scan angle. This model is suitable to stabilise the antenna admittance against wide scan and synthesis of any desired beam shape.