Yes / This paper presents a planar multi-circular loop antenna with a wide impedance bandwidth for next generation mm-wave systems. The proposed antenna comprises three circular rings with a partial ground plane with a square slot. The resonating structure is designed on a 0.254 mm thin RO5880 substrate with a relative permittivity of 2.3. The single element of the proposed design showed a resonance response from 26.5 to 41 GHz, with a peak gain of 4 dBi and radiation efficiency of 96%. The proposed multicircular ring antenna element is transformed into a four-element array system. The array size is kept at 18.25 × 12.5 × 0.254 mm3 with a peak gain of 11 dBi. The antenna array is fabricated and measured using the in-house facility. The simulated and measured results are well agreed upon and are found to be suitable for mm-wave communication systems.

This thesis can be viewed as two parts. The first part focuses on performance analysis of millimeter wave (mmWave) communications. We investigate how the interference behaves in the outdoor mesh network operating at 60-GHz when block age and shadowing are present using the probability of collision as a metric, under both the protocol model and the physical model. In contrast with results reported in mmWave mesh networks at 60-GHz that advocates that interference has only a marginal effect, our results show that for a short-range link of 100 m, the collision probability gets considerably larger (beyond 0.1) at the signal-to-interference-plus-noise ratio (SINR) of interest (for example, the reference value is chosen as 15 dB for uncoded quadrature phase shift keying (QPSK)). Compensation or compromise should be made in order to maintain a low probability of collision, either by reducing transmitter node density which is to the detriment of the network connectivity, or by switching to a compact linear antenna array with more at-top elements, which places more stringent requirements in device integration techniques. The second part of this thesis focuses on finding the optimal unmanned aerial vehicle (UAV) deployment in the sense that it can maximize over specific network connectivity. We have introduced a connectivity measure based on the commonly used network connectivity metric, which is refered to as global soft connectivity. This measure can be easily extended to account for different propagation models, such as Rayleigh fading and Nakagami fading. It can also be modified to incorporate the link state probability and beam alignment errors in highly directional networks. As can be shown, under the line-of-sight (LOS) and Rayleigh fading assumptions, the optimization regarding the global soft connectivity can be expressed as a weighted sum of the square of link distances between the nodes within the network, namely the ground-to-ground links, the UAV-to-UAV links and the ground-to-UAV links. This can be shown to be a quadratically constrained quadratic program (QCQP) problem with non-convex constraints. We have also extended our global connectivity to other types of connectivity criteria: network k-section connectivity and k-connectivity. In all the three cases, we have proposed a heuristic and straightforward way of finding the suboptimal UAV locations. The simulation results have shown that all these methods can improve our network connectivity considerably, which can achieve a gain of up to 30% for a five UAV scenario.

Yes / In the equivalent frequency-based model, the antenna array gain is utilised to characterise the frequency response of the beam squint effect generated by the antenna array. This impact is considered for a wide range of uniform linear array (ULA) and uniform planar array (UPA) designs, including those with and without tapering configurations. For a closer look at how the frequency response of the array adapts to the variations in the incidence angle of the signal, the bandwidth of the spectrum is varied and investigated. To study this effect, we have considered using the gain array response as an equivalent channel model in our approach. Beam squinting caused by distortion in the frequency response gain can be verified by one of two equalisers: a zero-forcing (ZF) equaliser or a minimum mean square error (MMSE) equaliser. Different cases with their analysis and results are studied and compared in terms of coded and uncoded modulations. / This work was supported in part by the Satellite Network of Experts V under Contract 4000130962/20/NL/NL/FE, and in part by the Innovation Program under Grant H2020-MSCA-ITN-2016 SECRET-722424.

Two experiments were conducted to investigate Adaptive Noise Cancelling and Cepstrum echo removal post-processing techniques on acoustic data from a linear microphone array in an anechoic chamber. A point source speaker driven with white noise was used as the primary signal. The first experiment included a background speaker to provide interference noise at three different Signal-to-Noise Ratios to simulate noise propagating down a wind tunnel circuit. The second experiment contained only the primary source and the wedges were removed from the floor to simulate reflections found in a wind tunnel environment. The techniques were applicable to both signal microphone and array analysis. The Adaptive Noise Cancellation proved successful in its task of removing the background noise from the microphone signals at SNRs as low as -20 dB. The recovered signals were then used for array processing. A simulation reflection case was analyzed with the Cepstral technique. Accurate removal of the reflection effects was achieved in recovering both magnitude and phase of the direct signal. Experimental data resulted in Cepstral features that caused errors in phase accuracy. A simple phase correction procedure was proposed for this data, but in general it appears that the Cepstral technique is and would be not well suited for all experimental data. / Master of Science

The Thermal Radiation Group, a laboratory in the Department of Mechanical Engineering at Virginia Polytechnic Institute and State University, is currently working to develop a new technology for thermal radiation detectors. The Group is also studying the viability of replacing current Earth Radiation Budget radiometers with this new concept. This next-generation detector consists of a thermopile linear array thermal radiation detector. The principal objective of this research is to develop an optical model for the detector and its cavity. The model based on the Monte-Carlo ray-trace (MCRT) method, permits parametric studies to optimize the design of the detector cavity and the specification of surface optical properties. The model is realized as a FORTRAN program which permits the calculation of quantities related to the cross-talk among pixels of the detector and radiation exchange among surfaces of the cavity. An important capability of the tool is that it provides estimates of the discrete Green's function that permits partial correction for optical cross-talk among pixels of the array. / Master of Science

Vehicle-related communications are a key application to be enabled by Fifth Generation (5G) wireless systems. The communications enabled by the future Internet of Vehicles (IoV) that are connected to every wireless device are referred to as Vehicle-to-Everything (V2X) communications. A major application of V2X communication systems will be to provide emergency warnings. This thesis evaluates Long-Term Evolution (LTE) and Dedicated Short Range Communications (DSRC) in terms of service quality and latency, and provides guidelines for design of cooperative LTE-DSRC systems for V2X communications. An extensive simulation analysis shows that (1) the number of users in need of warning has an effect on latency, and more so for LTE than for DSRC, (2) the DSRC priority parameter has an impact on the latency, and (3) wider system bandwidths and smaller cell sizes reduce latency for LTE. The end-to-end latency of LTE can be as high as 1.3 s, whereas the DSRC latency is below 15 ms for up to 250 users. Also, improving performance of systems is as much as important as studying about latency. One method to improving performance is using a better suitable antenna for physical communication. The mobility of vehicles results in a highly variable propagation channel that complicates communication. Use of a smart, steerable antenna can be one solution. The most commonly used antennas for vehicular communication are omnidirectional. Such antennas have consistent performance over all angles in the horizontal plane; however, rapidly steerable directional antennas should perform better in a dynamic propagation environment. A linear array antenna can perform dynamical appropriate azimuth pattern by having different weights of each element. The later section includes (1) identifying beam pattern parameters based on locations of a vehicular transmitter and fixed receivers and (2) an approach to find weights of each element of linear array antenna. Through the simulations with our approach and realistic scenarios, the desired array pattern can be achieved and array element weights can be calculated for the desired beam pattern. Based on the simulation results, DSRC is preferred to use in the scenario which contains large number of users with setup of higher priority, and LTE is preferred to use with wider bandwidth and smaller cell size. Also, the approach to find the controllable array antenna can be developed to the actual implementation of hardware with USRP. / Master of Science

<p>Two methods for evaluating and improving plane wave beamforming have beendeveloped. The methods estimate the shape of the wavefront and use theinformation in the beamforming. One of the methods uses estimates of the timedelays between the sensors to approximate the shape of the wavefront, and theother estimates the wavefront by matching the received wavefront to sphericalwavefronts of different radii. The methods are compared to a third more commonmethod of beamforming, which assumes that the impinging wave is planar. Themethods’ passive ranging abilities are also evaluated, and compared to a referencemethod based on triangulation.Both methods were evaluated with both real and simulated data. The simulateddata was obtained using Raylab, which is a simulation program based on ray-tracing. The real data was obtained through a field-test performed in the Balticsea using a towed array sonar and a stationary source emitted tones.The performance of the matched beamformers depends on the distance to the tar-get. At a distance of 600 m near broadside the power received by the beamformerincreases by 0.5-1 dB compared to the plane wave beamformer. At a distance of300 m near broadside the improvement is approximately 2 dB. In general, obtain-ing an accurate distance estimation proved to be difficult, and highly dependenton the noise present in the environment. A moving target at a distance of 600 mat broadside can be estimated with a maximum error of 150 m, when recursiveupdating of the covariance matrix with a updating constant of 0.25 is used. Whenrecursive updating is not used the margin of error increases to 400 m.</p>

<p>DNA samples from crime scenes or mass disasters are often limited and degraded which limits the possibility of successful traditional STR analysis. Moreover, there is a need to decrease the turnaround time in criminal investigations. These circumstances require a wider set of assays and technologies to be investigated for potential use in forensic DNA analysis, which has been explored in this thesis work. DNA analysis can also provide a useful tool in forensic pathology investigations. </p><p>In a search for mutations involved in The Sudden Infant death Syndrome (SIDS), the entire mitochondrial genome was sequenced in six SIDS infants and shorter mtDNA regions were analysed in paraffin-embedded tissues from an additional 14 SIDS cases. In this sample material no mutations associated with SIDS were found that could explain the death of these infants. </p><p>To reduce time, cost and effort related to sequencing of the mtDNA HVI/HVII regions in caseworks, a HVI/HVII mtDNA linear array assay was used as a pre-screening for exclusions of suspects or evidence samples. Using this assay, 56% of the samples involved in casework analysis could be excluded before sequencing was undertaken.</p><p>The possibility to use the new array technology was explored in a SNP assay targeting both mtDNA and nuclear SNPs. The system relies on minisequencing in solution prior to hybridisation to tag arrays. Using this system, we demonstrate a rapid, highly multiplexable and flexible array-format for SNP analysis.</p><p>The properties of the Pyrosequencing technology being a fast and user-friendly assay was utilised in a study to investigate the possibility to use this method for limited and degraded samples. Ten STR loci, overlapping with standardised kits, were genotyped in 114 Swedish individuals. We found additional variation and higher resolution of repeats at some of these loci that are not detected using standard fragment analysis.</p>

DNA samples from crime scenes or mass disasters are often limited and degraded which limits the possibility of successful traditional STR analysis. Moreover, there is a need to decrease the turnaround time in criminal investigations. These circumstances require a wider set of assays and technologies to be investigated for potential use in forensic DNA analysis, which has been explored in this thesis work. DNA analysis can also provide a useful tool in forensic pathology investigations. In a search for mutations involved in The Sudden Infant death Syndrome (SIDS), the entire mitochondrial genome was sequenced in six SIDS infants and shorter mtDNA regions were analysed in paraffin-embedded tissues from an additional 14 SIDS cases. In this sample material no mutations associated with SIDS were found that could explain the death of these infants. To reduce time, cost and effort related to sequencing of the mtDNA HVI/HVII regions in caseworks, a HVI/HVII mtDNA linear array assay was used as a pre-screening for exclusions of suspects or evidence samples. Using this assay, 56% of the samples involved in casework analysis could be excluded before sequencing was undertaken. The possibility to use the new array technology was explored in a SNP assay targeting both mtDNA and nuclear SNPs. The system relies on minisequencing in solution prior to hybridisation to tag arrays. Using this system, we demonstrate a rapid, highly multiplexable and flexible array-format for SNP analysis. The properties of the Pyrosequencing technology being a fast and user-friendly assay was utilised in a study to investigate the possibility to use this method for limited and degraded samples. Ten STR loci, overlapping with standardised kits, were genotyped in 114 Swedish individuals. We found additional variation and higher resolution of repeats at some of these loci that are not detected using standard fragment analysis.

Two methods for evaluating and improving plane wave beamforming have beendeveloped. The methods estimate the shape of the wavefront and use theinformation in the beamforming. One of the methods uses estimates of the timedelays between the sensors to approximate the shape of the wavefront, and theother estimates the wavefront by matching the received wavefront to sphericalwavefronts of different radii. The methods are compared to a third more commonmethod of beamforming, which assumes that the impinging wave is planar. Themethods’ passive ranging abilities are also evaluated, and compared to a referencemethod based on triangulation.Both methods were evaluated with both real and simulated data. The simulateddata was obtained using Raylab, which is a simulation program based on ray-tracing. The real data was obtained through a field-test performed in the Balticsea using a towed array sonar and a stationary source emitted tones.The performance of the matched beamformers depends on the distance to the tar-get. At a distance of 600 m near broadside the power received by the beamformerincreases by 0.5-1 dB compared to the plane wave beamformer. At a distance of300 m near broadside the improvement is approximately 2 dB. In general, obtain-ing an accurate distance estimation proved to be difficult, and highly dependenton the noise present in the environment. A moving target at a distance of 600 mat broadside can be estimated with a maximum error of 150 m, when recursiveupdating of the covariance matrix with a updating constant of 0.25 is used. Whenrecursive updating is not used the margin of error increases to 400 m.