Some limitations in the broadband operation of segmented reflectors

Arrays of finite conducting linear elements are often used to approximate solid reflectors in applications where weight and windloading make it impractical to use large, solid surfaces. A common configuration for such an array is achieved by simply connecting the centres of the linear elements by a single structural member such that the reflector is an array of parasitic dipoles excited by a driven element located in front of the reflector. Theoretical and experimental data obtained for several plane, corner and parabolic reflector configurations show that distinct resonances, characterized by narrowband fluctuations in the radiation pattern may seriously affect the operation of these antennas. Adjustment of the reflector element length and spacing provides an effective means of controlling these resonances.