Microwave transmission-line-based chirped electromagnetic bandgap structures

Although the concepts of chromatic dispersion and chirp are far from new in the world of wireless microwave communication, their application has always been constrained by the limited bandwidths, insertion losses and integration issues of dispersive devices. Often, a microwave designer seeking to incorporate chirping would fall back on surface-acoustic-wave structures, which are very lossy and do not easily penetrate into the GHz frequency-band, or else photonics-based solutions (e.g. chirped fiber Bragg gratings), which provide high bandwidths but incur integration and cost issues. This is in part due to the perceived lack of a convenient dispersive structure in electronics that is sufficiently low-loss and broadband in the GHz frequency range. Such a structure has in fact been recently demonstrated: it is a chirped electromagnetic bandgap (CEBG), and our work has explored its potential in a number of ultra-wideband sub-systems designed to perform a variety of signal processing tasks. Of particular interest is the close-fitting synergy between the operational frequencies of this new structure and the rapidly emerging ultra-wideband (UWB) wireless technology, which strives to handle signals with fractional bandwidths that can exceed 100%---a task for which CEBGs are well-suited.This thesis details the first demonstrations of several practical microwave sub-systems made possible by employing dispersive CEBG structures implemented in transmission-line technologies at a bare minimum of cost and complexity. Many of these demonstrations challenge the assumption that transduction to the optical or acoustic domain is required in order to perform dispersion-enabled tasks on very broadband electrical signals.Among the first-time demonstrations explored in the course of this thesis are: (1) passive, real-time Fourier transformations using CEBG structures, enabling time-domain measurement and processing based on the frequency content of signals; (2) UWB tunable time-delay systems, capable of voltage-controlled, continuously-adjustable nanosecond-scale delays; (3) temporal imaging systems, for which we demonstrate a 5X time-magnification system for distortionless bandwidth-conversion; and (4) multi-frequency resonators designed to pass a number of resonant channels in a very broad stopband. Each demonstrated system represents a simple, fully-electronic solution to challenges facing the microwave community in subjects as diverse as analog-to-digital conversion, UWB communication, and arbitrary waveform generation