UWB Technology

Ultra Wide Band (UWB) technology has attracted increasing interest and there is a growing demand for UWB for several applications and scenarios. The unlicensed use of the UWB spectrum has been regulated by the Federal Communications Commission (FCC) since the early 2000s. The main concern in designing UWB circuits is to consider the assigned bandwidth and the low power permitted for transmission. This makes UWB circuit design a challenging mission in today's community. Various circuit designs and system implementations are published in this book to give the reader a glimpse of the state-of-the-art examples in this field. The book starts at the circuit level design of major UWB elements such as filters, antennas, and amplifiers; and ends with the complete system implementation using such modules

Hybrid integration of synthesized dielectric image waveguides in substrate integrated circuit technology and its millimeter wave applications

Analysis, design, and fabrication of the SIIG -- Mode excitation in the SIIG -- Integrated dielectric antennas -- SIIG bends and power splitting/combining -- The SIIG in the context of substrate integrated circuits

Novel MMIC design process using waveform engineering

It has always been the case that talented individuals with an innate understanding of their subject have been able to produce works of outstanding performance. The purpose of engineering science is to define ways in which such achievements can be made on a regular,predictable basis with a high degree of confidence in success. Some tools, such as computers, have enabled an increase in speed and accuracy, whilst others have given a dramatic increase in the insight into the operation or behavior of materials; the electron microscope for instance. Still others have enabled the creation of devices on a scale unimaginable to our predecessors, Molecular Beam Epitaxy for example. This work is the product of the availability of an understanding of complex theory on microwave transistor operation, significant increases in mathematical processing and data handling, and the assembly of a ‘tool’ that not only allows the measurement of high frequency waveforms, but their manipulation to simultaneously create the environments envisioned by the design engineer. It extends the operation of previous narrow band active load pull measurement systems to 40GHz and importantly facilitates the design of high efficiency modes at X band. The main tenant of this work is to propose that rather than the linear approach of characterisation, design, test, re-iterate, that has been the standard approach to MMIC design to date, the first three stages should be integrated into a single approach which should obviate the need for design reiteration. The result of this approach should be better performance from amplifier designs, greater probability of success first time, and lower costs through less wafer real estate being consumed and fewer sign ‘spins’

Finite difference time domain analysis of microstrip antenna-circuit modules

Compact microstrip antenna-circuit modules, which could be used as front-ends for future wireless systems applications, require electromagnetic modelling due to the close interaction of the circuit with the antenna. Spectrum crowding and EMC/EMI issues call for modelling of the radiation of such modules. Coupling through fringing fields and the nonlinearities of active devices must be addressed. In this work, the FDTD method was used because it can provide the framework for inclusion of circuit elements in a full wave calculation. A software tool was developed and validated based on this method. The modules studied were chosen due to their compactness and their merit as system components. A module with simultaneous transmit-receive operation integrating an active circulator (using amplifiers in a ring-like arrangement) and a quarter wavelength antenna was analysed. Coupling effects were identified and their impact on the radiation patterns was shown. Electronically tuneable microstrip patch antennas using varactor diodes were also studied. Tuning range and harmonic radiation were demonstrated. Single and dual device Gunn oscillator antennas were analysed and their radiation patterns were calculated for the first time. All of our results were in agreement with experimental findings

Tunable microwave filters using ferroelectric thin films

Frequency agile microwave devices based on Barium Strontium Titanate (BST) thin films have gained a lot of interest in recent years. The frequency agility of the ferroelectric devices is based on the external DC electric field controlled permittivity of BST thin film. In this research work, several tunable microwave filters incorporating BST thin film varactors operating in a frequency range between 1 GHz and 25 GHz are designed, tested and analysed. A lumped element lowpass filter incorporating integrated meander line inductors and BST parallel plate capacitors is implemented on a high resistivity silicon substrate and demonstrates 32.1 % tuning of the cut-off frequency at 15 V. A combline bandpass filter employing integrated BST parallel plate varactors as tuning elements is implemented on a MgO substrate and shows a reasonable tuning from about 8 GHz to 12 GHz with 10 V bias of only one resonator. Two pole and four pole coupled resonator bandpass filters with discrete BST or GaAs varactors as tuning elements are implemented in a frequency range of 1 - 3 GHz. The filters based on BST parallel plate capacitors show an insertion loss in line with the GaAs filters, which is also the lowest insertion loss of BST filters ever reported. Future work on improving the BST film and metal film loss at tens of gigahertz range is also discussed