Ultra-High Q-Factor Silicon Resonator for High Frequency Oscillators

The thesis focuses on the investigation and characterisation of ultra-high Q-factor low loss Silicon resonators with transverse electric (TE)-like electromagnetic band-gap determined by two dimensional periodic structure made of a Silicon slab having a triangular lattice of air cylinders. A band-gap is observed where no energy is propagated through the slab, however engineering defects are created and optimised within the lattice producing resonant cavities and waveguides. The structure being excited with the fundamental TE10 mode can be coupled to external circuits via waveguides and its respective transitions in co-planar waveguide transmission line used to convey the millimetre-wave frequency signals. The ultimate goal is to investigate and characterise the promising low loss and high frequency Silicon resonators suitable for millimetre-wave communications such as used in low phase noise oscillator application and band pass filters. The results clearly show that electromagnetic band-gap structures or photonic crystals (PC) can be utilized for application in high frequency oscillators directly in fundamental mode with great benefits in obtaining ultra-high Q-factor and therefore low phase noise; and with better performance than alternative state-of-art technologies such as crystal oscillators in combination with frequency multiplication or frequency synthesis causing an increase in the overall phase noise by 20 log rule. By successfully demonstrating the experiment of using electromagnetic band-gap structures with oscillators, it is a great contribution towards the solution of the problem of high phase noise affecting high frequency oscillators operating at millimetre-wave band.