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Electrical and electronic engineering
Antennas for impulse radio ultra-wideband based portable devices are required to be compact and able to transmit or receive waveforms with minimal distortion in order to support proximity ranging with a centimetre-scale precision. The first part of thesis characterises several pulse types for use in the generation of picosecond-scale signals in respect to the regulatory power and frequency standards while the principles of antenna transient transmission and reception are stated. The proximity effect of planar conductors on the performance of an ultra-wideband antenna is investigated in both spectral and temporal domain demonstrating the relationship between the antenna-reflector separation and the antenna performance. Balanced and unbalanced antennas are also investigated for integration into asset-tracking tag applications and are designed to operate in close proximity to PCB boards while meeting realistic dimensional constraints and acceptable time domain performances. Monopole antenna designs are reported with performances optimized for minimum pulse dispersion. Minimization of pulse dispersion effects in the antenna designs is achieved using pulses with optimal spectral fit to the UWB emission mask. The generation of these waveforms are reported for the first time. An antenna de-embedding method is reported enabling validation of the simulated fidelity factor of radiated patterns. Novel differentially-fed planar dipole and slot antennas are reported for direct IC output integration. Design objectives and optimisation are focused on bandwidth enhancement and pulse dispersion minimisation. Finally, time- and frequency-domain measurements are carried out using an approach based on the superposition principle.
Dumoulin, A.: A Study of Integrated UWB Antennas Optimised for Time Domain Performance. Doctoral Thesis. Dublin Institute of Technology, 2012.