A Frequency Diversity Printed-Yagi Antenna Element for Apertures Selectivity Wideband Array Application

Abstract

A wideband frequency diversity printed-Yagi antenna array is presented. The operating band of the single port L-/S-bands antenna element can be selected by changing the states of p-i-n diode switches. The L- and S-bands work independently. A $4 \times 4$ S-band array can be constituted to a $2 \times 2$ L-band array by modifying the element apertures. This array operates at 1–2 GHz/2–4 GHz in the L-/S-bands with a fractional bandwidth of 66.7%/66.7%, which is translated into an overall tuning ratio of 4:1. The spacing of adjacent antenna elements at each reconfigurable mode is less than $0.72\lambda _{0}$ ( $\lambda _{0}$ represents the free-space wavelength of the highest frequency in the operating band), which achieves no grating lobes in the radiation field. The proposed antenna array is simulated, fabricated, and tested with reasonable agreement between measurements and simulations. In this way, a rudiment of wider tuning ratio array is designed for wideband reconnaissance applications.