A reconfigurable parasitic antenna with continuous beam scanning capability in H-plane

Abstract

A reconfigurable microstrip Yagi antenna is proposed to realize continuous and improved beam scanning from −40 to 40 in the H-plane. The antenna is designed using a square shaped driven patch and two hexagonal slotted tunable parasitic elements placed in the H-plane. The mutual coupling between the driven and tunable parasitic elements is controlled by changing the capacitance of varactor diodes loaded in the hexagonal slot. The relative lead and lag of current due to change in the dimension of tunable parasitic patch causes phase distribution across the elements resulting in continuous scanning of the main beam. The performance of the antenna is measured in three operating modes namely Reflector-Director (RD), Director-Reflector (DR) and broadside. In RD and DR mode, the main beam is continuously scanned from 14.4 to 40 and −14.4 to −40 respectively. The main beam is directed to 0 in the broadside mode with a gain of 3.36 dBi. The antenna achieves overall bandwidth from 2.43 to 2.47 GHz in all the operating modes without any impedance matching network. The reflection and radiation performance of the fabricated antenna shows good agreement with the simulation results.