Printed Yagi-Uda Antenna for Directivity Reconfiguration Using Ring Resonators

This paper describes a printed Yagi-Uda antenna structured by ring resonators acting as parasitic directors capable of being activated or deactivated to achieve directivity reconfiguration at an operation frequency of 1.87 GHz. The antenna approach exhibits a good performance for applications that require modifying its radiation pattern in terms of directivity while frequency, polarization and the rest of properties remain almost invariable. Simulations and measurements of the reflection coefficient magnitudes as well as the radiation patterns show a good agreement. Furthermore, simulations verify a directivity increment of about 3.8 dB by changing the antenna structure from a 3-element to a 5-element printed Yagi-Uda antenna.