A Reconfigurable Pattern Loop Antenna for Wireless Applications

This letter presents a new low-profile, reconfigurable pattern antenna. The antenna features a printed circular segmented loop fed by two separate feed points coupled to a parasitic composite right/left-handed transmission line (CRLH TL). The key innovation of this design lies in its ability to switch between the three modes, monopole-like, broadside, and directive, by electronically controlling the PIN diodes, allowing for dynamic adjustment of the radiation pattern. In directive mode, the antenna's beam can be steered electronically in the azimuth plane, while the monopole-like and broadside patterns are achieved through phase difference adjustments between the antenna ports. A prototype has been fabricated and tested, demonstrating a measured impedance bandwidth of 50 MHz (|S11|