Most signal processing / communications applications heavily rely on filters. For
adaptive spectrum filtering and for applications that switch between sets of different
filter implementations, it would be beneficial to utilize just one, tuneable band-pass
filter.
In recent years, the study of metamaterials emerged as an area of scientific
research due to the unique attributes of metamaterials. Metamaterials typically are
artificial structures with properties not found in nature, for instance negative refraction
indexes. Their feature sizes span a fraction of the wavelength corresponding to their
frequency of operation. A sub group of metamaterials, the electromagnetic bandgap
(EBG) structures, exhibit stopbands for electromagnetic waves irrespective of
polarization or angle of incidence. EBG structures prominently achieved surface wave
suppression to minimise cross talk between neighbouring devices and improving
antenna efficiency by acting as a perfect magnetic conductor within a certain frequency
range.
The thesis investigates the suitability of EBG structures for filter implementations.
The goal is to provide a tuneable band-pass filter for adaptive spectrum filtering and
communication applications. The bandgap of an infinite array of EBG cells is
numerically determined. Based on those results, an EBG band-pass filter
implementation on a printed circuit board (PCB) is designed, fabricated and
characterized. Different tuning methods were incorporated into the PCB design to create
a tuneable EBG band-pass filter. An EBG filter was built on a fused silica wafer, in
order to shift the passband to higher frequencies.