In this thesis, we propose a cost-based CLEAN algorithm to accurately find dense multi-path parameters and improve the performance of selective RAKE receiver in indoor UWB systems. RAKE receiver can resolve the dense multi-path interference problems with the multi-path parameters. Because the weak paths are of lower valuable for system performance improvement, selective RAKE receiver combines only the strongest multi-path components and reduce the number of fingers to lower the complexity of RAKE receiver. However, selective RAKE receiver needs accurate multi-path detection to decide the suitable number and parameters of fingers. In order to improve the performance of selective RAKE receiver, the main issue in this thesis is to detect the best paths of channel with the CLEAN algorithm. CLEAN algorithm uses the correlation of the received signal and the template signal as the basis for searching paths. If there are closely adjacent paths, or if one of signal paths is relatively stronger, the detection error of paths may occur and thus affects the performance of the receiver. EP-based CLEAN algorithm uses the cost function and the evolutionary programming (EP) to search the multi-path delay times and gain coefficients for minimizing the cost function. Accurate multi-path detection and high resolution of adjacent paths can be obtained. However, EP-based CLEAN algorithm makes a time-consuming blind search. In the thesis, a CLEAN algorithm based on the cost function is proposed. The proposed cost-based CLEAN algorithm searches the delay times near the peaks of the cross-correlation for local minimum of the cost function, and then uses CLEAN algorithm to extract autocorrelation components and obtain the accurate multi-path detection. By testing the IEEE802.15.3a UWB channel models, and comparing with CLEAN algorithm, the cost-based CLEAN algorithm in the thesis can achieve better detection accuracy in multi-path searching, and improve the performance of selective RAKE receiver.

<p>In this thesis, design aspects of fully integrated multibandmultistandard front-end receivers are investigated based onthree fundamental aspects: noise, linearity and operatingfrequency. System level studies were carried out to investigatethe effects of different modulation techniques, duplexing andmultiple access methods on the noise, linearity and selectivityperformance of the circuit. Based on these studies and thelow-cost consideration, zero-IF, low-IF and wideband-IFreceiver architectures are promising architectures. These havea common circuit topology in a direct connection between theLNA and the mixer, which has been explored in this work toimprove the overall RF-to-IF linearity. One front-end circuitapproach is used to achieve a low-cost solution, leading to anew multiband multistandard front-end receiver architecture.This architecture needs a circuit whose performance isadaptable due to different requirements specified in differentstandards, works across several RF-bands and uses a minimumamount ofexternal components.</p><p>Five new circuit topologies suitable for a front-endreceiver consisting of an LNA and mixer (low-noise converter orLNC) were developed. A dual-loop wide-band feedback techniquewas applied in all circuits investigated in this thesis. Threeof the circuits were implemented in 0.18 mm RF-CMOS and 25 GHzbipolar technologies. Measurement results of the circuitsconfirmed the correctness of the design approach.</p><p>The circuits were measured in several RF-bands, i.e. in the900 MHz, 1.8 GHz and 2.4 GHz bands, with S11 ranging from–9.2 dB to–17 dB. The circuits have a typicalperformance of 18-20 dB RF-to-IF gain, 3.5-4 dB DSB NF and upto +4.5 dBm IIP3. In addition, the circuit performance can beadjusted by varying the circuit’s first-stage biascurrent. The circuits may work at frequencies higher than 3GHz, as only 1.5 dB of attenuation is found at 3 GHz and nopeaking is noticed. In the CMOS circuit, the extrapolated gainat 5 GHz is about 15 dB which is consistent with the simulationresult. The die-area of each of the circuits is less than 1mm2.</p>

<p>Radar warning systems are life saving equipment in modern fighter aircraft. It is therefore vital that the system can tell the difference between a threat genuine frequency) and a false signal (spurious frequency). </p><p>This thesis presents a model aimed at predicting the frequencies and other parameters in the RF converter of the radar warning system. The components of the RF converter have been studied, measured, and modelled. The modelling tool has been the Simulink toolbox for Matlab. </p><p>Extreme accuracy has been sacrificed in order to make the model easy to use for the working engineer. Instead, this model presents a rough estimate of some of the most important properties of the radar warning system with just a few data sheet figures as input.</p><p>The simulation results are satisfactory as a whole. Simulink is the limiting factor in the implementation of the model. Significantly improved results can probably be obtained by working in another software environment.</p>

The availability of low-cost wireless devices has enabled wide-scale connectivity over recent years. Today’s wireless devices provide services including voice communication, GPS location, and internet connectivity. With a larger number of supported wireless standards within a single device, new wireless radio techniques are required in order to implement flexible and programmable broadband receivers to replace the standard specific receivers often seen today. The continual growth in the use of the wireless spectrum has led to an increasingly hostile interference environment for such receivers. While interferers may be located out of the signal band of interest, they may still reside within the large band of operation of the broadband receiver, making removal of the interference by filtering difficult. The requirement for small form-factor and cost minimization has made an increased level of integration highly desirable to minimize the number of external filter components required to reject interferers. A key consideration in the design of broadband receivers is the spurious response of the downconversion mixers, where local oscillator (LO) harmonics can lead to downconversion of unfiltered interferers to baseband, along with the desired signal, thus degrading the signal-to-noise ratio. Recent broadband receivers utilize a harmonic rejection mixer to reject LO harmonics within the downconversion mixer and prevent interferers from being downconverted to baseband. This report details the cause of harmonic mixing within CMOS mixers and provides a survey of published circuit techniques robust to device mismatch to remove LO harmonic response. A description of frequency translation and the effect of harmonic mixing on the translation is presented. The theoretical background of the operation of harmonic rejection mixers is described, including the effect of gain and phase errors on the achievable level of harmonic rejection. An overview of published harmonic rejection mixer techniques including the first harmonic rejection mixer and techniques to limit the effects of phase and gain mismatch on harmonic rejection is discussed. The report concludes with the introduction of a novel method for effective synthesis of multiple downconversion local oscillator frequencies within a harmonic rejection mixer. The proposed method reduces the tuning range required of the downconversion oscillator in broadband applications. Based on Monte Carlo simulations, while considering device mismatches over a 3σ spread, harmonic rejection better than 63 dB is observed for all selectable LO frequencies. / text

The Western U.S. has experienced widespread extension during the past 10’s of millions of years, largely within the Basin and Range and Rio Grande Rift provinces. Tomography results from previous studies revealed narrow fast seismic velocity anomalies in the mantle on either side of the Rio Grande Rift as well as at the western edge of the Colorado Plateau. The fast mantle anomalies have been interpreted as down-welling that is part of small scale mantle convection at the edge of extending provinces. It was also found that crust was thicker than average ab¬¬ove the possible mantle down-welling, indicating that mantle dynamics may influence crustal flow. We present results from P/S conversion receiver functions using SIEDCAR (Seismic Investigation of Edge Driven Convection Associated with the Rio Grande Rift) data to determine crustal and lithospheric structure beneath the east flank of the Rio Grande Rift. Crustal and lithosphere thickness are estimated using P-to-S and S-to-P receiver functions respectively. Receiver function migration methods were applied to produce images of the crust and lithosphere. The results show variable crustal thickness through the region with an average thickness of 45 km. The crust achieves its maximum thickness of 60km at 105W longitude, between 33.5N and 32.2N latitude. This observation confirms previous receiver function results from Wilson et al, 2005. Body wave tomography (Rocket, 2011; Schmandt and Humphreys, 2010) using similar data to what we used for the receiver function analysis, shows mantle downwelling closely associated with the thickened crust. We believe that the thickened crust might be due to lower crustal flow associated with mantle downwelling or mantle delamination at the edge of the Rio Grande Rift. In this model the sinking mantle pulls the crust downward causing a pressure gradient within the crust thus causing the flow. Our S-P images show signal from the lithosphere-asthenosphere boundary (LAB) with an average LAB thickness of 100 km but with a sharp transition at about 1050 W from 75 km to over 100 km. The region with abnormally thick crust overlies a region where the lithosphere appears to have a break. We interpret our results as showing that lower lithosphere has and is delaminating near the edge of the Great Plains accompanied by lower crustal flow in some places determined by lower crustal viscosity. / text

In multicell coordinated networks where multiple base stations cooperate to jointly combat interference from adjacent cells and fading to receivers, one of the outstanding questions is what is the role of receive antenna and receiver processing. Multiple receive antennas not only enable additional degrees of freedom at each receiver to combat the other-cell interference but also can change the transmitter design because transmitter and receiver beamforming design is often closely coordinated. In this dissertation, we investigate the role of the multiple receive antennas in multicell cooperative systems under different interference conditions. We then present novel non-iterative and iterative coordinated beamforming and precoding algorithms with different receiver processing. We present comprehensive performance comparison of various multicell cooperative systems and explore the feasibility of achieving much higher throughput via hyper-densification of heterogeneous and small cell networks with mandatory multicell cooperation. / text

An open systems architecture (OSA) is one in which all of the interfaces are fully defined, available to the public, and maintained according to a group consensus. One approach to achieve this is to use modular hardware and software and to buy commercial, off-the-shelf and commodity hardware. Benefits of an OSA include providing easy access to the latest technological advances in both hardware and software, enabling net-centric operations, and allowing a flexible design that can easily change as the needs of customers may change. This paper will provide details of an OSA system designed for a telemetry receiver and list the benefits of OSA for the telemetry community.

A new receiver concept utilizing impinging jet cooling technology has been developed for a small scale solar dish-Brayton system. In a typical impinging receiver design, the jet nozzles are distributed evenly around the cylindrical absorber wall above the solar peak flux region for managing the temperature at an acceptable level. The absorbed solar irradiation is partially lost to the ambient by radiation and natural convection heat transfer, the major part is conducted through the wall and taken away by the impingement jets to drive a gas turbine. Since the thermal power requirement of a 5 kWe Compower® micro gas turbine (MGT) perfectly matches with the power collected by the EuroDish when the design Direct Normal Irradiance (DNI) input is 800 W/m2, the boundary conditions for the impinging receiver design in this work are based on the combination of the Compower®MGT and the EuroDish system. In order to quickly find feasible receiver geometries and impinging jet nozzle arrangements for achieving acceptable temperature level and temperature distributions on the absorber cavity wall, a novel inverse design method (IDM) has been developed based on a combination of a ray-tracing model and a heat transfer analytical model. In this design method, a heat transfer model of the absorber wall is used for analyzing the main heat transfer process between the cavity wall outer surface, the inner surface and the working fluid. A ray-tracing model is utilized for obtaining the solar radiative boundary conditions for the heat transfer model. Furthermore, the minimum stagnation heat transfer coefficient, the jet pitch and the maximum pressure drop governing equations are used for narrowing down the possible nozzle arrangements. Finally, the curves for the required total heat transfer coefficient distribution are obtained and compared with different selected impinging arrangements on the working fluid side, and candidate design configurations are obtained. Furthermore, a numerical conjugate heat transfer model combined with a ray-tracing model was developed validating the inverse design method and for studying the thermal performance of an impinging receiver in detail. With the help of the modified inverse design method and the numerical conjugate heat transfer model, two impinging receivers based on sintered α-SiC (SSiC) and stainless steel 253 MA material have been successfully designed. The detailed analyses show that for the 253 MA impinging receiver, the average air temperature at the outlet and the thermal efficiency can reach 1071.5 K and 82.7% at a DNI level of 800 W/m2 matching the system requirements well. Furthermore, the local temperature differences on the absorber can be reduced to 130 K and 149 K for two different DNI levels, which is a significant reduction and improvement compared with earlier published cavity receiver designs. The inverse design method has also been verified to be an efficient way in reducing the calculation costs during the design procedure. For the validation and demonstration of the receiver designs, a unique experimental facility was designed and constructed. The facility is a novel high flux solar simulator utilizing for the first time Fresnel lenses to concentrate the light of 12 commercial high power Xenon-arc lamps. Finally, a prototype of a 253 MA based impinging was experimentally studied with the help of the 84 kWe Fresnel lens based high flux solar simulator in KTH. / <p>QC 20151123</p> / Optimised Microturbine Solar Power System , OMSOP

Detta examensarbete handlar om trådlös batteriladdning. Arbetet har utförts genom Jörgensen Industrielektronik AB, ett företag som specialiserat sig på kundanpassade elektroniklösningar. Företaget utvecklade en ny produkt, där det skulle finnas som tillval att den kunde laddas trådlöst. En mottagare för trådlös laddning av produktens batterier utvecklades. Mottagaren utvecklades utifrån Qi-standarden som beskrivs i denna rapport. Mottagarens elektriska egenskaper bestämdes (t.ex. effektivitet och laddström). EMCtester av mottagaren utfördes för att undersöka hur mycket störningar mottagaren genererade. Arbetet resulterade i en mottagare som kunde ladda produktens batterier med en befintlig Qi-laddstation. Effektiviteten hamnade på en nivå som är vanlig för trådlös laddning, jämfört med ledningsbunden laddning så var effektiviteten lägre. Resultatet av EMCtesterna visade att mottagaren genererade elektromagnetiska störningar, men emissionsnivåerna var inom gränserna för de EMC-standarder mätningarna har jämförts med. / The subject of this thesis is wireless battery charging. The thesis has been made in collaboration with Jörgensen Industrielektronik Ltd, specialized in costumer adapted electronics. The company developed a new product, where wireless charging was an optional feature. In this thesis a wireless charging receiver was developed. The receiver was intended for charging the batteries in the product. The receiver was developed according to the Qi standard. The Qi standard is described in this report. EMC tests were performed on the receiver in order to examine the levels of emissions radiated. The work resulted in a receiver that was able to charge the product's batteries with an existing Qi charging station. The efficiency was normal for wireless charging, compared to wired charging the efficiency was lower. The EMC tests showed that the receiver radiates electromagnetic energy. The radiated emissions were within the limits of the EMC standards that the measurements have been tested against.

This thesis investigates near-field wireless power transfer using multiple transmitters or multiple receivers. First, transmitter diversity is investigated in terms of the power transfer efficiency (PTE). It is found that an improvement in the PTE can be achieved by increasing the number of transmitters. Furthermore, a region of constant PTE can be created with the proper arrangement of transmitters. Next, receiver diversity is investigated in detail. An improvement in the PTE can be also achieved by increasing the number of receivers. However, it is shown that when two or more receivers are closely located, the PTE is reduced due to mutual coupling between receivers. This is termed a ‘sink’ phenomenon, and it is investigated through measurement and simulation. Finally, to account for more general situations of multiple transmitters and multiple receivers, Monte-Carlo simulation is applied. The cumulative distribution function (CDF) is used to interpret the results of the Monte-Carlo simulation. The transmitter and receiver diversity gain can be found based on the CDF. Moreover, the sink phenomenon can be observed by analyzing the CDF curve. Several strategies for positioning receivers are introduced to reduce the sink phenomenon. The results of the Monte-Carlo simulation also show that a saturation in the transmitter or receiver gain is reached when the number of transmitters or receivers is increased. Therefore, increasing the number of transmitters or receivers beyond a certain number does not help increase the PTE. / text