Miniaturization of waveguide antennas using electromagnetic metamaterials

In the era of miniaturized hand - held devices rectangular waveguides have been replaced by planar guiding structures in many of the applications for miniaturizations. Use of waveguides is inevitable in many applications. Waveguides offer a number of advantages over planar guiding structures, viz., lower loss and high power handling capability, absence of substrate mode losses etc. Waveguide manufacturing cost and their size at microwave frequencies are the biggest disadvantages. Over the years a number of researchers have tried to miniaturize waveguides. Classical waveguide miniaturization is by filling the waveguides with a dielectric yielding to size reduction of 1/ relative to an empty waveguide. The disadvantages of such dielectric filled waveguides are, high cost and such waveguides cannot be used as an antenna.

In this thesis we propose an open - ended rectangular waveguide antenna loaded with broadside coupled split - ring resonators (BC-SRR) radiating below the cutoff frequency of the waveguide. An X-Band, open - ended waveguide antenna loaded with BC-SRR operating in a 5.5-6.7 GHz frequency band was designed, fabricated and tested.