Compact and Efficient Millimetre-Wave Circuits for Wideband Applications

Radio systems, along with the ever increasing processing power provided by computer technology, have altered many aspects of our society over the last century. Various gadgets and integrated electronics are found everywhere nowadays; many of these were science-fiction only a few decades ago. Most apparent is perhaps your ``smart phone'', possibly kept within arm's reach wherever you go, that provides various services, news updates, and social networking via wireless communications systems. The frameworks of the fifth generation wireless system is currently being developed worldwide. Inclusion of millimetre-wave technology promise high-speed piconets, wireless back-haul on pencil-beam links, and further functionality such as high-resolution radar imaging. This thesis addresses the challenge to provide signals at carrier frequencies in the millimetre-wave spectrum, and compact integrated transmitter front-ends of sub-wavelength dimensions. A radio frequency pulse generator, i.e. a ``wavelet genarator'', circuit is implemented using diodes and transistors in III--V compound semiconductor technology. This simple but energy-efficient front-end circuit can be controlled on the time-scale of picoseconds. Transmission of wireless data is thereby achieved at high symbol-rates and low power consumption per bit. A compact antenna is integrated with the transmitter circuit, without any intermediate transmission line. The result is a physically small, single-chip, transmitter front-end that can output high equivalent isotropically radiated power. This element radiation characteristic is wide-beam and suitable for array implementations

Single Photon Manipulation

This short book aims to present basic information about single photons in a quick read but with not many details. For this purpose, it only introduces the basic concept of single photons, the most important method of generating single photons in experiments, and a specific emerging field

An experimental study of propagation in multimode optical waveguides using spatially incoherent probe techniques

The analysis of propagation in waveguides is generally based Upon Maxwell's Equations and yields solutions in the form of sets of orthogonal fields called characteristic modes of the waveguide. If numerous modes are excited simultaneously by a single monochromatic source, the intensity distribution measured within the waveguide will be the coherent superposition of all the excited modal fields. The analysis of this coherent superposition is cumbersome for all but a small number of modes. If the source is polychromatic or spatially incoherent the increased complexity of the superposition procedure, which must now consider the relative coherence of modes, suggests that this method is inappropriate. [Continues.