Effects of Radome’s Frequency Selection Surface on the Radiation Pattern of a Slotted Waveguide Antenna Array

Slotted waveguide antenna array used to be the main stream of military aircraft radar antenna, but in recent decade has been replaced by Active Electronically Scan Antenna (AESA) due to low observability requirements. However, slotted waveguide antenna still has the narrow beam width and high gain advantage. To reduce the radar cross section (RCS) of slotted waveguide antenna array, frequency selection surface (FSS) is often used to reduce out of band reflection. In this article we examine the effects of FSS on the radiation pattern of slotted waveguide antenna array using a method of moment (MOM) simulation. We find the peak gain is not affected very much, but the side lobs changes more The phase however changes considerably by the FSS, which needs to be corrected when using AESA.