Digital RF phase shifters fabricated using additive manufacturing processes are presented and studied. The purpose is to explain the performance differences between phase shifters fabricated using additive manufacturing and those fabricated with conventional subtractive techniques. All phase shifters are designed to operate at a center frequency of 2.45 GHz with a 100 MHz bandwidth. The 1-bit 45° switched line phase shifters have an average insertion loss of 1.3 dB and a 220 mm2 footprint, while the 1-bit 180° high-pass low-pass phase shifters have an insertion loss 1.56 dB and a 180 mm2 footprint. The 4-bit high-pass low-pass, switched line hybrid phase shifters on the other hand show an average state insertion loss of 5.4 dB and have a 660 mm2 foot print. By carefully analyzing the performance of the various phase shifter designs it is shown that the limiting factors of additive manufacturing technology are the low conductivity of CB028 silver ink in comparison to copper, and the inability to print dielectrics with low surface roughness. Finally, parallel plate capacitors and a spiral inductor designed to be fabricated using additive manufacturing techniques are studied. This is done in order to better understand the advantages and disadvantages of such a design. By analyzing the component’s simulated performance it is shown that 3D printed capacitors and inductors are feasible as long as the capacitance or inductance values needed are low. Large value 3D printed components are impractical for RF applications due to their large size.

This thesis aims toward developing strategies in the area of structural optimization and to implement these strategies in design processes. At   GM Powertrain Sweden where powertrains are designed and developed, two designs of a differential housing have been chosen for this thesis. The main tasks have been to perform a topology optimization of a model early in a design process, and a shape optimization on a model late in a design process. In addition the shape optimization strategies have also been applied on a fork shifter. This thesis covers the theory of different optimization strategies in general. The optimization processes are explained in detail and the results from the structural optimization of the differential housings as well as the fork shifter are shown and evaluated. The evaluation of the thesis provides enough arguments to suggest an implementation of the optimization strategies in design processes at GM Powertrain. A Structural Optimization group has great potential of closing the gap between structural designers and structural analysis engineers which in long terms mean that better structures can be developed in less time. To be competitive in the automotive industry these are two of the most important factors for being successful.

Owing to the large electric-field-dependent permittivity, ferroelectric thin films have attracted a great deal of attention on applications in miniature tunable microwave components with high performance and cost reduction, such as phase shifters, tunable oscillators, delay lines, and antennas. These tunable devices require large change in the dielectric constant with applied field and a low loss at microwave frequencies. As one of the promising ferroelectric materials, barium strontium titanate thin film, especially Ba0.5Sr0.5TiO3 (BST) films, have raises great research interests due to its high dielectric constant, which is tunable in an external electric field, combined with relative low loss at microwave frequencies. Tunable microwave components, such as phase shifter, based on the BST films have been widely investigated. Since the polarization, the significant characterization of ferroelectrics, is very sensitive to distortion in crystal structure of ferroelectrics, strain can be effectively utilized to tailor the dielectric properties of BST films. Due to the lattice-mismatch from the substrate and various deposition conditions, epitaxial BST thin film usually contains residual strain generated during film growth. Strain control by improved deposition technique and implementing thermal treatment as well as choosing suitable substrate has attracted intensive attentions in ferroelectric film fabrication. Theory predicts that high dielectric properties can be achieved when free strain or slightly tensile strain left in the BST thin film at room temperature. Microwave application, such as phase shifter, also expects the enhanced tunability by an applied electric field. In this dissertation, single crystalline BST thin films deposited by radio frequency magnetron sputtering on SrTiO3 and DyScO3 substrates were studied. The crystal structure characteristics, including lattice parameters and film strain, were determined using X-ray diffraction. A new growth technique, three-step technique, was introduced and implemented into BST thin film deposition. The application of this new technique in deposition dramatically reduced the compressive strain in the films. We use microwave measurements on coplanar waveguides to evidence the improvement on dielectric properties achieved by tailoring the film strain. Additionally, we studied the BST film deposited by pulsed laser deposition (PLD) with introducing a sputtered seed layer of BST thin film. Compared with the BST film directly deposited on the substrate by PLD deposition, the films with a seed layer showed a large enhancement on the dielectric constant and tunability. The discussion on the change in film strain and dielectric performance of the PLD deposited films further proved the influence of film strain on dielectric properties. We discussed the design, fabrication, and measurement of coplanar waveguide transmission lines as phase shifters fabricated BST films. The thin BST films (~700 nm) on DyScO3 substrates deposited by sputtering demonstrated that the three-step deposition technique improved differential phase shift and microwave figure of merit to a great extent. The introduction of the sputtered seed layer into the PLD deposition of a thicker BST film (~2.15 μm) showed a dramatically enhancement on differential phase shift and microwave figure of merit. The enhanced performance on different series of BST films in microwave frequencies is consistent with the improvement on crystal structure, especially with the change in film strain.

Engineers know well from an early point in their training the trials and tribulations of having to make design tradeoffs in order to optimize one performance parameter for another. Discovering tradeoff conditions that result in the elimination of a loss associated with the enhancement of some other parameter (an improvement over a typical tradeoff), therefore, ushers in a new paradigm of design in which the constraints which are typical of the task at hand are alleviated. We call such a design paradigm “tuning” as opposed to “trading off”, and this is the central theme of this work. We investigate two types of microwave electronic devices, namely GaN-based heterostructure field effect transistors (HFETs) and tunable ferroelectric-ferrite-based microwave phase shifters. The “tuning” associated with these types of devices arises from the notion of an optimal 2DEG density, capable of achieving higher performance in terms of electron velocity and enhanced reliability in the case of the HFET, and the coupling of ferroelectric and ferrite materials in tunable microwave phase shifters, capable of achieving high differential phase shifts while at the same time mitigating the losses associated with impedance mismatching which typically arise when the phase is tuned. Promises and problems associated with HFET devices based on the intriguing InAlN/GaN material system will be described. We focus on the fundamental problem associated with the induction of the large density of carriers at the interface, namely the disintegration of an excess of longitudinal optical phonons (hot phonons) in the channel. We use microwave measurements in conjunction with stress tests to evidence the existence of an optimal 2DEG density wherein the hot phonon effect can be “tuned,” which allows for enhanced high frequency performance as well as device reliability. Next, we focus on the design, fabrication, and measurement of tunable phase shifters consisting of thin films of BaxSr1-xTiO3 (BST), which has the advantage of having high dielectric tunability as well as relatively low microwave loss. We discuss the design, fabrication, and measurement of a simple coplanar waveguide (CPW) type of phase shifter as well as a more complicated “hybrid” phase shifter consisting of a ferrite (YIG) in addition to BST. The use of such a bilayer allows one to “tune” the impedance of the phase shifters independently of the phase velocity through careful selection of the DC biasing magnetic fields, or alternatively through the use of an additional piezoelectric layer, bonded to YIG whose permeability can then be tuned through magnetostriction.

Este trabalho, realizado junto ao Grupo de Novos Materiais e Dispositivos (GNMD) pertencente ao Laboratório de Microeletrônica (LME) da Universidade de São Paulo, teve como objetivo correlacionar algumas propriedades físico-químicas de filmes finos de Ba1-XSrxTiO3 (BST), obtidos pela técnica de pulverização catódica reativa (sputtering), com os parâmetros de deposição, visando a fabricação de defasadores inteligentes operando em 60 GHz. Propriedades como cristalinidade e composição química foram estudadas e relacionadas com o tipo de substrato sobre o qual os filmes finos de BST foram depositados, e com os diversos parâmetros de deposição variados. Foi observada uma forte influência dos parâmetros de deposição, principalmente da temperatura e do tipo de substrato, na cristalinidade dos filmes. Os filmes depositados sobre cobre são mais cristalinos do que aqueles depositados sobre Si. Já a composição química dos filmes não variou significativamente, mantendo-se próxima à do alvo de sputtering utilizado, independentemente do substrato ou das condições de deposição. As propriedades elétricas dos filmes fabricados foram extraídas de capacitores de placas paralelas construídos utilizando o BST como dielétrico linear. As curvas de capacitância vs tensão a 1 MHz destes capacitores permitiram determinar uma variação de tunabilidade de até 44 %, para uma permissividade elétrica relativa de 310, valores estes compatíveis com aqueles encontrados na literatura. As propriedades elétricas dos filmes produzidos permitiram projetar um defasador de 1,3 mm2, com uma figura de mérito de 30º/dB para uma defasagem de 360º. / This work, performed at the New Materials and Devices Group (GNMD) of the Microelectronics Laboratory of the Polytechnic School of the University of São Paulo, has the objective to correlate reactive sputtered-BST thin films to its deposition parameters, aiming to produce a 60 GHz tunable phase shifter. Thin film crystallinity and stoichiometry were correlated with sputtering deposition parameters and the type of substrate. A strong influence of the sputtering parameters was observed on BST crystallinity, mainly the temperature and the type of substrate. Thin films on copper are more crystalline than on Si (100). The stoichiometry, on the other hand, did not change as function of the deposition parameters or the substrate in both cases. The thin films electrical properties were obtained by capacitance vs voltage measurements, with the BST as linear dielectric of a parallel plate capacitor. The capacitors 1 MHz C-V characterization showed tunabilities as high as 44%, for an electrical permittivity of 310. These properties allowed a phase shifter project, resulting a 1,3 mm2 device with a figure of merit of 30 º/dB for 360 º phase shift.

Este trabalho, realizado junto ao Grupo de Novos Materiais e Dispositivos (GNMD) pertencente ao Laboratório de Microeletrônica (LME) da Universidade de São Paulo, teve como objetivo correlacionar algumas propriedades físico-químicas de filmes finos de Ba1-XSrxTiO3 (BST), obtidos pela técnica de pulverização catódica reativa (sputtering), com os parâmetros de deposição, visando a fabricação de defasadores inteligentes operando em 60 GHz. Propriedades como cristalinidade e composição química foram estudadas e relacionadas com o tipo de substrato sobre o qual os filmes finos de BST foram depositados, e com os diversos parâmetros de deposição variados. Foi observada uma forte influência dos parâmetros de deposição, principalmente da temperatura e do tipo de substrato, na cristalinidade dos filmes. Os filmes depositados sobre cobre são mais cristalinos do que aqueles depositados sobre Si. Já a composição química dos filmes não variou significativamente, mantendo-se próxima à do alvo de sputtering utilizado, independentemente do substrato ou das condições de deposição. As propriedades elétricas dos filmes fabricados foram extraídas de capacitores de placas paralelas construídos utilizando o BST como dielétrico linear. As curvas de capacitância vs tensão a 1 MHz destes capacitores permitiram determinar uma variação de tunabilidade de até 44 %, para uma permissividade elétrica relativa de 310, valores estes compatíveis com aqueles encontrados na literatura. As propriedades elétricas dos filmes produzidos permitiram projetar um defasador de 1,3 mm2, com uma figura de mérito de 30º/dB para uma defasagem de 360º. / This work, performed at the New Materials and Devices Group (GNMD) of the Microelectronics Laboratory of the Polytechnic School of the University of São Paulo, has the objective to correlate reactive sputtered-BST thin films to its deposition parameters, aiming to produce a 60 GHz tunable phase shifter. Thin film crystallinity and stoichiometry were correlated with sputtering deposition parameters and the type of substrate. A strong influence of the sputtering parameters was observed on BST crystallinity, mainly the temperature and the type of substrate. Thin films on copper are more crystalline than on Si (100). The stoichiometry, on the other hand, did not change as function of the deposition parameters or the substrate in both cases. The thin films electrical properties were obtained by capacitance vs voltage measurements, with the BST as linear dielectric of a parallel plate capacitor. The capacitors 1 MHz C-V characterization showed tunabilities as high as 44%, for an electrical permittivity of 310. These properties allowed a phase shifter project, resulting a 1,3 mm2 device with a figure of merit of 30 º/dB for 360 º phase shift.

<p><p><p>This thesis aims toward developing strategies in the area of structural optimization and to implement these strategies in design processes. At</p><p> </p><em>GM Powertrain Sweden </em>where powertrains are designed and developed, two designs of a differential housing have been chosen for this thesis. The main tasks have been to perform a topology optimization of a model early in a design process, and a shape optimization on a model late in a design process. In addition the shape optimization strategies have also been applied on a fork shifter. This thesis covers the theory of different optimization strategies in general. The optimization processes are explained in detail and the results from the structural optimization of the differential housings as well as the fork shifter are shown and evaluated. The evaluation of the thesis provides enough arguments to suggest an implementation of the optimization strategies in design processes at <em>GM Powertrain</em><p>. A Structural Optimization group has great potential of closing the gap between structural designers and structural analysis engineers which in long terms mean that better structures can be developed in less time. To be competitive in the automotive industry these are two of the most important factors for being successful.</p></p></p>

In modern wireless communication and radar systems, filters play an important role in getting a high-quality signal while rejecting spurious and neighboring unwanted signals. The filters with reconfigurable features, such as tunable bandwidths or switchable dual bands, also play a key part both in realizing the compact size of the system and in supporting multi-communication services. The Chapters II-IV of this dissertation show the studies of the filters for microwave communication. Bandpass filters realized in ring resonators with stepped impedance stubs are introduced. The effective locations of resonant frequencies and transmission zeros are analyzed, and harmonic suppression by interdigital-coupled feed lines is discussed. To vary mid-upper and mid-lower passband bandwidths separately, the characteristic impedances of the open-circuited stubs are changed. Simultaneous change of each width of the open-circuited stub results in variable passband bandwidths. Asymmetric stepped-impedance resonators are also used to develop independently controllable dual-band (2.4 and 5.2 GHz) bandpass filters. By extending feed lines, a transmission zero is created, which results in the suppression of the second resonance of 2.4-GHz resonators. To determine the precise transmission zeros, an external quality factor at feeders is fixed while extracting coupling coefficients between the resonators. Two kinds of feed lines, such as hook-type and spiral-type, are developed, and PIN diodes are controlled to achieve four states of switchable dual-band filters. Beam-scanning features of the antennas are very important in the radar systems. Phase shifters using piezoelectric transducers and dielectric leaky-wave antennas using metal strips are studied in the Chapters V-VII of this dissertation. Meandered microstrip lines are used to reduce the size of the phase shifters working up to 10 GHz, and reflection-type phase shifters using piezoelectric transducers are developed. A dielectric film with metal strips fed by an image line with a high dielectric constant is developed to obtain wide and symmetrical beam-steering angle. In short, many techniques are presented for realizing reconfigurable filters and large beam-scan features in this dissertation. The result of this work should have many applications in various wireless communication and radar systems.

Detta examensarbete på C-nivå har genomförts i samarbete med Kongsberg Automotive i Mullsjö som utvecklar och tillverkar komponenter till fordons-industrin.Företaget har fått reklamationer på en växelväljare i deras sortiment och är en produkt som sitter i kundens lastbilar och bussar. Felen har uppträtt relativt sällan men med tillräckligt stor marginal för att de ska klassas som allvarliga fel. Dessa fel är kopplade till den magnetarm som kommunicerar med transmissionen i fordonet och konsekvensen av dessa fel blir att fordonet blir obrukbart och måste bärgas bort.Syftet med detta examensarbete är att författaren på ett ingenjörsmässigt sätt ska angripa problemen med magnetarmen till växelväljaren på så sätt att grundorsaken bakom kan säkerställas. Målet för arbetet är att hitta dessa grundorsaker till varför magnetarmen går sönder, eller hoppas ur sitt läge, samt att ta fram en design som hindrar att problemen uppstår igen.För att strukturera arbetet har författaren använt sig av en problemlösningsmetod som heter Six Sigma DMAIC. Det är den här metoden som hela projektet och därmed rapporten är uppbyggt kring.Författaren kom fram till att grundorsakerna till problemen som uppstått med magnetarmen hade grundat sig i konstruktionen av de komponenter som sköter funktionen med produktens växelknappar. Deras konstruktion har gjort det möjligt för föraren att felaktigt kunna aktivera två knappar samtidigt vilket ledde till att produkten påverkats på fel sätt.Examensarbetet resulterade i ett koncept som tillsammans med företagets egna framtagna lösning tar bort de bakomliggande grundorsakerna och förhindrar att problemen kan uppstå igen. / This bachelor thesis has been executed in cooperation with Kongsberg Auto-motive AB, Mullsjö, who develop and produce parts to the automotive industry.The company has received complaints on a gear lever unit which they produce and which sits in the customers’ trucks and buses. The failures have occurred relatively infrequently, but with enough margins to classify them as serious failures. These failures are connected to that magnet arm in the product which communicates with the transmission of the vehicle and leads to the consequence of an unusable truck that is in need of towing.The intent with this thesis is that the author should tackle the problems with the magnet arm on an engineering basis so that the root causes to the problems can be ascertained. The goal is to find these root causes to why the magnet arm breaks, or dislocates, and generate a design that prevents the problems from reappearing.To structure the work the author has used a method for problem solving called Six Sigma DMAIC which is the base for the whole project and therefore the thesis.Through extensive analyzes the author ascertained that the root causes for the problems with the magnet arm came from the design of parts, relating to the knob of the product, that enables two buttons to simultaneously be activated.The thesis resulted in a concept which together with the company´s solution removes the underlying root causes and prevents the problem from reappearing.

This paper presents a novel power management analysis method to reduce the power consumption for the non-contact vital sign sensor. The sensor consisting of the class-E power amplifier (PA), low noise amplifier (LNA), single pole double through (SPDT) switch, and circularly polarized antenna (CPA) is integrated on the Flame Retardant Class 4 (FR-4) epoxy-glass laminate substrate. The appropriate pulse width and pulse period are determined to decrease the power consumption and accurately detect the human physiological signals (respiration and heartbeat). A simple direct down-conversion architecture with a tunable phase shifter is utilized to eliminate the null detection point and the direct current (DC) offset. The overall power consumption of the proposed sensor with the novel power management technique is only 40 % of the conventional system with the DC bias, which can be utilized for the green energy application.