Metamaterials for Efficient Antenna Design

Abstract

In this thesis, the Composite Right/Left Handed (CRLH) transmission line and their exotic features are studied. Due to the unique properties CRLH unit cells can exhibit, they attracted the attention for possible use to tailor microwave devices with better properties than before.

Two antennas were loaded with CRLH unit cells and their performances were studied. The first antenna was a loop antenna loaded with four CRLH unit cells. The antenna accordingly operates at two bands covering different communication schemes. The radiation pattern of the antenna was omnidirectional and orthogonal at the two operating frequencies. It was fabricated and fed by a balun where the simulation and experimental results showed good agreement and its performance was better than previously presented similar antennas.

The other presented metamaterial inspired antenna is a microstrip patch antenna loaded with a CRLH unit cell. Loading the antenna with the CRLH unit cell makes it operate at three different bands which are not harmonically related covering dif- ferent communication standards. An equivalent circuit model for the patch loaded antenna was developed that can predict the current flow through the antenna and explains the three bands. The full wave and circuit simulations agreed well.