A Study of Integrated UWB Antennas Optimised for Time Domain Performance

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

Cellular Transport and Membrane Dynamics of the Glycine Receptor

Regulation of synaptic transmission is essential to tune individual-to-network neuronal activity. One way to modulate synaptic strength is to regulate neurotransmitter receptor numbers at postsynaptic sites. This can be achieved either through plasma membrane insertion of receptors derived from intracellular vesicle pools, a process depending on active cytoskeleton transport, or through surface membrane removal via endocytosis. In parallel, lateral diffusion events along the plasma membrane allow the exchange of receptor molecules between synaptic and extrasynaptic compartments, contributing to synaptic strength regulation. In recent years, results obtained from several groups studying glycine receptor (GlyR) trafficking and dynamics shed light on the regulation of synaptic GlyR density. Here, we review (i) proteins and mechanisms involved in GlyR cytoskeletal transport, (ii) the diffusion dynamics of GlyR and of its scaffolding protein gephyrin that control receptor numbers, and its relationship with synaptic plasticity, and (iii) adaptative changes in GlyR diffusion in response to global activity modifications, as a homeostatic mechanism

Optimised Tapered-Slot Antenna for Real Time Location Systems

The design of a directional UWB tapered slot antenna for use within an asset tracking system is reported. The spline-based geometry was refined with a local optimization algorithm and a square root raised cosine pulse. The time-domain performance of the antenna is dependent on the optimisation method

An Enhanced Method to Measure Pulse Dispersion in UWB Antennas

This paper will demonstrate a method to remove the dispersive effects of antennas and measurement equipment from a real time-domain measurement setup. By isolating the AUT transfer function, more accurate time-domain measurements can be achieved and agreement to simulation improved

Performance Evaluation of Antennas for UWB Radar and Positioning Systems

This paper presents a study of the performance of three antennas for ultra wideband radio ranging systems. By using different pulse types, the performance of the antennas is measured and quantified by using the Fidelity Factor

Optimized Monopole and Dipole Antennas for UWB Asset Tag Location Systems

Miniaturized monopole and dipole antenna designs are reported with performances optimized for ultrawideband pulsed radio applications. The geometries are created using Bézier spline shapes, which have been refined with a genetic algorithm to simultaneously take account of both frequency- and time-domain criteria. Time-domain measurements of ultra wideband antennas with uniformly distributed energy across the full 3.1-10.6 GHz mask are reported for the first time and validate a new approach to minimization of pulse dispersion effects in the antenna designs

Infrared Thermography applied to transport infrastructures monitoring: outcomes and perspectives

International audienceLong term monitoring of transport infrastructures by infrared thermography has been studied and tested on different structures. A first standalone infrared system architecture developed is presented and discussed. Results obtained with such system on different Civil Engineering structures are presented. Some data processing approaches and inverse thermal model for data analysis are introduced and discussed. Lessons learned from experiments carried out in outdoor with such system are listed and analyzed. Then, a new generation of infrared system architecture is proposed. Finally, conclusions and perspectives are addressed