Radiation pattern shaping of higher order broadside modes of circular microstrip radiator using impedance surfaces

TM₁₁ mode of circular patch antenna is commonly used for broadside applications. Higher order broadside modes are studied in this paper. Radiation pattern shaping of these modes has been attempted here to make them useful for various applications. The evolution of designs is inspired by the concept of metascreens. Significant sidelobe reduction is achieved in TM₁₂ and TM₁₃ modes which ultimately lead to novel antenna configurations. The principal idea here is to tailor the current distribution on patch surface via using array subwavelength slots and making it behave as a low impedance surface to get the desired pattern.