Ground plane edge serrations for improved performance of microstrip active reflectarray elements

The paper investigates the effects of ground plane edge serrations on microstrip patch antennas for use in active-element reflectarray applications. Improvements in isolation between the ports of the antenna by this ground plane edge treatment are studied once the microstrip patch geometry has been modified to incorporate the active device. This treatment not only improves the general characteristics of the radiating element, but can also act to stabilize the output and reduce uncontrolled oscillations and other undesired behaviors.