Mask Programmable CMOS Transistor Arrays for Wideband RF Integrated Circuits

A mask programmable technology to implement RF and microwave integrated circuits using an array of standard 90-nm CMOS transistors is presented. Using this technology, three wideband amplifiers with more than 15-dB forward transmission gain operating in different frequency bands inside a 4-22-GHz range are implemented. The amplifiers achieve high gain-bandwidth products (79-96 GHz) despite their standard multistage designs. These amplifiers are based on an identical transistor array interconnected with application specific coplanar waveguide (CPW) transmission lines and on-chip capacitors and resistors. CPW lines are implemented using a one-metal-layer post-processing technology over a thick Parylene-N (15 mum ) dielectric layer that enables very low loss lines (~0.6 dB/mm at 20 GHz) and high-performance CMOS amplifiers. The proposed integration approach has the potential for implementing cost-efficient and high-performance RF and microwave circuits with a short turnaround time

Design and Reliability of mm-Wave Circuits In Silicon-Germanium

The first goal of this research is to develop a methodology for the design of RF and mm-Wave circuits in Silicon-Germanium utilizing CMOS, PIN diodes, and passive circuits. Such circuits consist of a 2-20 GHz CMOS-based TR (Transmit/Receive) SPDT switch and an 18-47 GHz Wilkinson Power Divider-Combiner (WPDC). Optimal design techniques are utilized in these circuit designs to overcome the limitations of both Front End of the Line (FEOL: active devices) and Back End of the Line (BEOL: metal stack-up) in a commercial SiGe BiCMOS processes. The resulting performances utilize novel design techniques that allow them to be competitive with existing state-of-the-art designs across multiple IC technologies. The second goal of this research is to understand the impact of DC reliability mechanisms on AC performance for analog SiGe HBT circuits and to locate an optimal DC biasing regime that balances the tradeoff between circuit reliability and performance. The circuit of interest is a DC-100 GHz wireline driver, which is widely used as a critical block in optical communications. The aim is to extend the concept of Safe Operating Area (SOA), which is the region of the DC I-V plane that does not damage a device over time, to the circuit level. This is done with the introduction of a performance-informed Circuit Safe Operating Area (C-SOA), which is defined as the region of the DC I-V plane that does not result in a degradation to AC performance over time while maintaining the best possible AC performance. The wireline driver’s highlighted AC performance is the OP1dB or output referred 1-dB compression point.M.S

High-Power Comb-Line Filter Architectures for Switched-Mode RF Power Amplifier Systems

Die vorgelegte Arbeit behandelt die Analyse der Anforderungen, denschaltungstechnischen Entwurf, den Aufbau und die messtechnische Verifizierungvon Rekonstruktionsfiltern für Leistungsschaltverstärker im Klasse-SBetrieb, die auf Grund ihres hohen Wirkungsgrades vorzugsweise in MobilfunkbasisstationenVerwendung finden sollen. Die Brauchbarkeit des Entwurfeswird an Hand einer Reihe von Applikationsbeispielen anschaulich dargestellt.Als Kernforderung einer derartigen Filterauslegung hat sich die Aufrechterhaltungder Rechteckzeitfunktion des Drain-Stromes für einen (im ”CurrentMode” arbeitenden) Schaltverstärker herausgestellt, weil sonst die damit erzielbarehohe Effizienz nicht erreicht werden kann. Darüber hinaus fließen indie Filterauslegung nicht nur die Fixierung des Filterdurchlass- und sperrbereichesein, sondern auch die Festlegung der Eingangs- und Lastimpedanz bei unterschiedlichenAnregungsmoden über einen breiten Frequenzbereich. Doppelundeinzelterminierte Filter werden theoretisch betrachtet, simuliert, getestetund gemessen.Es wurde herausgearbeitet, dass die schaltungstechnischen und geometrischenAnforderungen an einen derartigen Rekonstruktionsfilterentwurf gutdurch symmetrisch gespeiste Kammleitungsfilter erfüllt werden können. VerschiedeneFilterarchitekturen werden im Hinblick auf ihr Gleich- und Gegentaktaktimpedanzverhaltenvorgestellt, experimentell untersucht und kritischanalysiert. Soweit dem Autor bekannt ist, werden hier erstmalig Rekonstruktionsfilterfür Klasse-S Leistungsverstärker im ”Current Mode” komplett analysiert.Desweiteren wird die Funktionalität des Rekonstruktionsfilters an Handanderer Typen von Leistungsschaltverstärkern simuliert und messtechnisch untersucht.Der maximale Wirkungsgrad von 65% bei Leistungsschaltverstärkersystemenlässt sich dem erfolgreichen Filterentwurf zuschreiben.This work has taken place in the context that a class-S power amplifiersystem with simplified transmitter architectures and increased power efficiencymakes an attractive candidate for cellular phone base transceiver station applications.The author describes the requirements for, and a number of successfulimplementations of, a reconstruction filter suitable for such an amplifier system.In a current-mode class-S power amplifier system, crucial to the maintenanceof the rectangular shape of the drain current and thus to high efficiency arenot only the tailoring of pass-band and stop-band, but also the specification ofinput impedance for different modes of excitation over a wide frequency range.Doubly and singly terminated filters are subjected to theoretical consideration,simulation, testing and measurement. The main focus of the research is on thedesign of the reconstruction filter.It is found that the electrical and geometrical constraints for the designof a reconstruction filter are well satisfied by balanced input comb-line filters.Several filter architectures are proposed, experimentally investigated, and criticallyanalysed in terms of differential and common mode impedances. Thisis the first complete analysis of reconstruction filters for current mode class-Spower amplifier systems, as far as the author knows. Switched-mode poweramplifier systems which include the proposed filters are also simulated andmeasured under different driving conditions. The maximum power efficiencyof 65% to date in the switched-mode power amplifier systems can be attributedto the successful filter design

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

Design and fabrication of multi-fingered lines and antenna

Master'sMASTER OF ENGINEERIN

Application of Maxwell-Wagner polarisation in monolithic technologies

Imperial Users onl