Development of high performance microwaves, millimetres and terahertz antennas based on negative/gradient refractive index, and anisotropic metatronics
In this thesis, Metatronics have been applied to develop high performance antennas. This thesis added five new achievements to the scientific world. Firstly, a volumetric Negative Refractive Index (NRI) medium composed of Split Ring Resonators and Thin Wires (SRRs/TWs) is designed and incorporated with patch antenna operating at 10 GHz and 300 GHz. The gain is improved by 1.5dB. Secondly, a double sided NRI composed of Circular Split Ring Resonators and Thin Wires (CSRRs/TWs) employing a lens is proposed and characterized. The measured gain is improved from 6.5dB to 11.4dB. Thirdly, a new slotted waveguide antenna incorporated with Electrically Split Ring Resonator (ESRR) Metasurface (MTS) exhibiting NRI is proposed. The measured gain of the 10 GHz proposed antenna is improved from 6.7 dB to 10.5 dB. Furthermore, an anisotropic Low Epsilon Medium (LEM) ESRR-MTS is designed to focus the E-plane beam of the slotted antenna. The measured gain is improved by 4dB. Fourthly, high fabrication tolerance non-resonance and resonance GRIN MTS are proposed and characterized up to THz. The gain is improved from 6.7 to 11.3dB for 10 and 60 GHz antennas. Finally, a semi-analytical model based on transfer function is proposed to model THz Photoconductive antenna (PCA) excited by a femtosecond pulsed laser beam
