Active phased array antennas, generally consisting of a large number of antenna elements and integrated-circuit (IC) components, are essential for different applications like 5G/6G communications, radar, aerospace, satellite communications and so on. The study of radiation pattern measurements and analysis of pattern data is a pivotal step in characterizing and understanding the use of antennas in any application. Unwanted changes can be observed in the radiation pattern due to randomly failed elements, ICs, or IC channels in phased arrays. Hence, there is a vital need for fast testing and diagnosis to identify possible failures of these large antenna systems, before taking any immediate action to compensate for these changes. Due to integrated-circuits (IC) non-linearities and mutual coupling challenges, the existing deterministic and optimization-based fault detection techniques fail to provide reliable results in practical systems. Besides, it is desired to achieve real-time array diagnosis during in-field operation, which makes the problem even more challenging. In this thesis, a novel machine-learning assisted fault-detection algorithm is proposed which is trained by using sparse far-field measurements from a practical IC-integrated millimeter-wave (mm-wave) phased array prototype and fixed multi-probe measurement system (antenna dome). A global optimization approach is used as a benchmark for comparison to the state-of-the-art. The incorporation of machine learning techniques greatly improves the fault detection time and accuracy in comparison to global optimizers. Furthermore, studies based on the number of sampling points used and the varying number of faults are also conducted which indicate similar conclusions.

Radar technology requires high efficiency and wide bandwidth performance at high output powers. However, new developments like using Joint Communication and Radar Sensing (JCRS), pulse shaping, and amplitude tapering provides an additional requirement: amplitude modulation. To satisfy all of these requirements, a Load-Modulated Balanced Amplifier (LMBA) using a wideband Class E is designed for 2.9-3.4 GHz using GaN transistors. First, an accurate linear model for the transistor is presented. After this, a new state-space solution for a Class-E LMBA is derived. And lastly, a LMBA using a wideband Class E is presented. Using a lossless matching network, the GaN-based amplifier has an average drain efficiency of 81 % over the full 10 dB power back-off. However, the final design has an average drain efficiency of 45 % with a peak output power of 44 dBm.

The analysis of integrated front ends operated in the high-frequency regimes is addressed in this work. The analysis of these problems has been a critical bottleneck for decades due to the difficulties arising in adopting full-wave techniques. Assuming, as typical at lower frequencies, that the structures are planar leads to the inaccurate representation of some characteristic reactive behaviors. As a case in point, the characteristic impedance of transmission lines, whose thickness is comparable to the width, is not well represented by planar tools. Moreover, existing analytic formulas based on quasi-static approximations for the surrounding fields typically fail when the dynamic components of the fields are also affected by the stratifications. In this thesis, planar stratified media with transmission lines and radiators are considered to be part of the front end, with this latter being integrated (or in package) thanks to the systematic presence of a dielectric lens antenna.

As 5G mm-wave communication progresses toward higher frequencies to meet market demands, companies are being pushed to adopt cutting-edge technologies. Operating at these higher frequencies naturally leads to shorter wavelengths, which increases circuit density. This higher density, in turn, complicates heat management. A supplementary solution involving heatsink antennas has been proposed to address this issue. Recent research from the MS3 group introduces a cost-effective, dual-functional pin-fed shorted patch antenna designed to assist with heat dissipation. Although the integration of a heatsink significantly improves thermal management, it does so at the cost of electromagnetic (EM) performance, particularly affecting radiation pattern symmetry, cross-polarization levels, and bandwidth. This work builds upon the latest research by using the aforementioned design as a benchmark, exploring further improvements and addressing the challenges introduced by the heatsink. This work presents, for the first time, the use of differential feeding to address the performance degradation caused by the heatsink. Differential feeding has been shown to enhance radiation pattern symmetry, increase gain, and improve bandwidth in certain applications. Additionally, aperture coupling is employed to further enhance the impedance bandwidth of the shorted patch. The results at the element level indicate a 90% improvement in impedance bandwidth due to aperture coupling; however, this comes with a significant degradation in the radiation pattern. By integrating aperture-coupled differential feeding, this work demonstrates symmetric radiation patterns, an improved bandwidth compared to the benchmark, and reduced cross-polarization levels. At the array level, differential feeding leads to a higher degree of coupling than pin-fed patch arrays for spacing values less than or equal to 0.6λ. Furthermore, differential feeding improves gain, reduces cross-polarization levels, and enhances radiation pattern symmetry compared to the benchmark.

According to the World Health Organization, approximately 15 million neonates are born prematurely each year, which is more than 1 in 10 newborns. Premature birth disrupts the normal development of the neonate in the womb, which can result in various complications and health issues, necessitating continuous monitoring of vital signs to assess their health status.

Currently, the predominant monitoring approach involves the use of contact-wired sensors, which offer precise readings but are accompanied by specific drawbacks. One notable limitation is the utilization of strong adhesives to attach the sensor to the neonate's skin, causing pain and stress during removal. Additionally, the wired sensor hinders skin-to-skin contact care, which is proved to be crucial for the neonate's growth and development.

To address these drawbacks, a non-contact wireless approach using FMCW radar is proposed in this thesis project. The main aim is to develop a processing pipeline to monitor the vital signs of neonates with the radar. The core concept involves estimating the vital signs from the phase information corresponding to the chest movement of the monitoring target. This will be achieved through the implementation of an algorithm based on the short-time Fourier transform. Furthermore, this study also explores an approach to detect body movement, select near-steady state data segment and determine the range bin that is most relevant for the vital signs estimation.

The proposed pipeline aims to provide a more comfortable and efficient monitoring system for neonates, potentially overcoming the limitations of conventional contact-wired sensors and promoting better care for their overall well-being and development.

In the framework of this MSc thesis the analysis of core-shell leaky-wave lens antennas is presented, based on a combination of asymptotic and Physical Optics techniques. This study aims to develop an analysis approach which can be subsequently used for the optimization of the Fly’s Eye antenna concept, through enabling the investigation of shaped variations of the core lens. The main difficulty of this prospect refers to the surface of the core lens being in the near field of the leaky wave feeding structure, since the evaluation of the near field is in general a computationally inefficient process. Adhering to this conclusion, a big part of this thesis elaborates on a very fast approach for the derivation of the near field, through asymptotically approximating the involved integral expressions. More specifically, the presented method exploits the nature of the near field in the examined stratification through introducing an approximation in the integral expressions, which in turn enables their asymptotic evaluation in a straightforward manner. Subsequently, the near field on the core lens is combined with a set of Physical Optics techniques in order to develop a model for the integrated lens architecture of the Fly’s Eye antenna. Modelling the core-shell structure in such a manner enables its study in a much more computationally efficient fashion compared to the use of a full-wave simulator. In addition, it facilitates the investigation of structural alterations in the antenna concept, like shaped variations of the core lens. The derived model presented in this thesis also contributed to the measurement campaign of the Fly’s Eye antenna prototype, through identifying a problematic component in the assembled prototype.

Lunar dust presents a serious problem for future lunar rovers. Due to the charged nature of this fine dust, it tends to stick to sensitive elements like solar panels. It is clear that a system needs to be implemented in order to remove lunar dust to keep the output power of the solar panel at a satisfactory level. This paper develops the proof of concept electronics for a method sometimes called an electrodynamic screen, that uses electrostatic fields to sweep away the dust adhered to the surface of the solar panel. The electronics for this system needs to produce a high voltage three phase pulse wave in order to drive the electrodes placed on top of the solar panel. The design of the electrodes themselves are not part of this thesis, but it is the main subject of the companion thesis produced by other members of our group.

Planar lenses based on metasurfaces or resonant elements are typically narrowband due to phase wrapping, which is strongly frequency-dependent. On the contrary, true-time-delay (TTD) planar lenses, which do not resort to phase wrapping, can achieve large bandwidths. One convenient way to design wideband TTD lenses is by means of artificial dielectric layers (ADLs), which are stacks of sub-wavelength-period patch arrays embedded in a host medium to increase its effective permittivity to values higher than commercially available dielectrics. The procedure to retrieve the effective refractive index for a given ADL stratification is reported, as well as the synthesis of the multi-section transformers in ADL technology. Trade-offs including bandwidth, focal ratio, lens diameter, and thickness, are discussed and related to the manufacturing constraints of artificial dielectrics, such as the number of metal layers, maximum achievable effective permittivity, and smallest features realizable in printed circuit board technology. An example of design is also presented, operating from 70 to 140 GHz with a lens diameter of 11.5 wavelengths at the highest frequency. A modeling method for the analysis of a flat lens based on ADLs is presented. This consists of a combined geometrical optics (GO) / physical optics (PO) approach, where each GO ray is studied as a plane wave problem to evaluate the reflection/transmission through each unit cell of the lens. This analysis is extended to consider the bending of the rays through the lens and propagation through multiple unit cells.

This thesis is concerned with a first time demonstration of a high frequency scanning lens phased­-array with dynamic steering. Such phased­-array could provide the high gain, wide bandwidth, and steering capability that the next generation of wireless ap­plications requires. The phased-­array development was divided into three distinct parts. First, the electronic phase steering system was discussed and developed, and its stability was characterized over time. Results obtained over 24 hours indicated that the system would be stable to within 6° of high frequency output phase. The drifts in output amplitude remained to within 0.3dB. Next, the lens antenna elements were developed with a novel corrugated leaky ­wave feed that provides very high and broadband aperture efficiency. Antenna measurements have validated its ability to be a very aperture efficient radiator (>80%) with wide bandwidth (1:2). Scanning measurements have shown a 3dB scan loss at around 15°. Finally, the phase steer­ing and antenna elements were combined into a 4×1 array concept. Its behaviour was simulated and indicated again good performance with wide bandwidth (1:2) and high directivity (31.5dBi). Simulated scan loss was approximately 3dB at 20°. The amplitude and phase errors resulted in a SLL standard deviation of 0.63dB. The array prototype is currently awaiting completion of fabrication by DEMO at the TU Delft.

A key issue in current quantum computing interfaces is the dense interconnect between electronics at cryogenic temperature (CT) and room temperature (RT). Recently, progress has been made to move more control electronics from RT to CT, reducing interconnect overhead. The next step towards minimal interconnect is a direct wireline interface between RT and CT. This work presents a full­rate 10 Gb/s clock­and­data recovery circuit for a high speed serial link receiver operating at CT.

A novel phase detector is utilized to reduce power consumption by removing the need for both a pulse generator at the input and, a buffer between the phase detector and voltage controlled oscillator. Additionally, a digital delay­locked loop is added to improve the retiming margin, achieving higher jitter tolerance. Implemented in 40­nm CMOS, post­layout simulation shows a core power consumption of 3.89 mW from a 1.1­V supply at 10 Gb/s, producing an rms­jitter of 84 fs and an estimated jitter tolerance
of 1.1 UIpp at 10 MHz.

In recent years, quantum computers have become increasingly popular, with high-profile companies in-vesting more and more resources into the development of quantum-computing prototypes. Such interest is motivated by the exponential increase in the computing power that quantum computers offer over classical computers, which may be used in several practical applications, such as producing faster and more accurate solutions to machine learning algorithms, the quantum simulations of molecules for drug and material synthesis, techniques that combat cybersecurity threats, and more. Quantum processors are typically placed in a dilution refrigerator, which cools down the processor to near absolute zero to make use of their quantum behavior. These fridges are large in scale and require multiple long wires from the processor to the readout/control equipment, which mostly resides at room temperature. However, although this approach is suitable for currently available systems with few quantum bits (qubits), it is unpractical for future quantum computers, with thousands or millions of qubits, due to the interconnect bottleneck. One solution isto move the readout/control circuits closer to the processor to avoid the need for bulky unreliable interconnects. However, this has proven to be difficult due to the limited cooling power of the fridges, which is below a few Watts at 4 K and below a few mW at temperatures below 100 mK. These limitations stress the need for low power readout/control circuitry of the processor as the number of qubits in a single processor increases. This thesis focuses on an ultra-low-power cryogenic amplifier design for the readout of spin qubits.Only recently, the cryogenic performance of Silicon-Germanium Heterojunction Bipolar Transistors (SiGe HBT) has been demonstrated to be specifically suited for the cryogenic readout of spin qubits, because of their ultra-low-power and their high sensitivity. This thesis focuses on the standard SiGe HBT available in the IHP 0.13μm SG13G2 BiCMOS process and on an optimized variant with modified doping profiles for enhanced current gain. As a first step, a comprehensive cryogenic (4 K or 15 K) DC characterization of the SiGe HBTs, CMOS transistors, and resistors is performed. This data proves the suitability of such technology for cryogenic application and will enable the future integration of a complete qubit readout, including SiGe front-end amplification and CMOS back-end post-processing. The measurement results of the SiGe HBT characterization show outstanding cryogenic performance for low power applications, with an attain-able current gain in the standard HBT of 100, 500, and 1000 at a power dissipation of 61nW, 2μW and 30μW,respectively, and, for the modified HBT, of 100, 500 and 1000 at a power dissipation of 5.5nW, 90nW, and140nW, respectively. To mimic the spin qubit readout, a discrete amplifier employing a SiGe HBT produced in the IHP SG13G2process has been built and used to characterize a single-electron transistor (SET), with both the SET and the amplifier operating at 4 K. By comparing the charge-stability diagram measured with room-temperature equipment, the proper operation of the proposed amplifier is demonstrated. Furthermore, the amplifier characterization showed a gain > 40 dB with an 113 kHz -3-dB bandwidth, and Signal-Noise Ratio (SNR)above 10 dB for a total measurement time of t<10μs, thus demonstrating performance compatible with the requirements for single-shot readout in state-of-the-art spin-qubit computers. Overall, the results show the capabilities of the SiGe HBT in low power cryogenic applications as well as the capabilities of the 0.13μmBiCMOS technology for the future full integration of qubit readout schemes.

Neonates are among the most fragile in the human population. Even more so when born prematurely. Their loss of development time in the womb disrupts their growth, and the neonatal intensive care unit environment can add multiple stresses that hinder their development. This can partly be attributed to the intrusive environment of a neonatal intensive care unit incubator. Neonatal development cannot be monitored without multiple wires and sensors, such as pulse oximetry and electrocardiogram (ECG). The strong adhesives of these sensors can hurt the delicate skin of the neonates and the sensors make bonding with parents difficult. The issue of the intrusive nature of current neonatal healthcare has led this thesis towards something not normally associated with healthcare: radar. Millimeter wave radar with frequency modulation of the continuous wave transmission has been shown to measure adult’s heart and respiration rate without contact with the patient. Using the small wavelength and high configurability of frequency modulated millimeter wave radar, the goal will be to scale down this technology from adults to neonates that can be as small as 500 grams. This thesis provides a look into the application investigation of frequency modulated millimeter wave radar in monitoring neonates. It dives into the environment of the neonatal intensive care unit incubator and the radar monitoring system operation. The environment is modelled with a thermal focus to avoid high temperature increases caused by the radar module. The system operation is described and the most influential component simulated and characterized. Lastly, the thermal model of the neonatal intensive care unit incubator is validated to understand how the system operation influences the environment. And the radar system operation will be characterized for measuring the smallest amplitude changes of a chest to understand how the environment influences the system performance. The conclusion of this thesis will provide reasoning for why or why not the application of frequency modulated millimeter wave radar has the capability to be safely implemented in the neonatal intensive care unit.

IoT refers to a network of connected devices that exchange data for different applications using different wireless standards such as Cellular, ZigBee, Bluetooth, Mesh Networks, and the widely used WiFi. For IoT applications that do not require high data rates but require long-range data transmission and low power operation, a sub 1GHz WiFi standard - 802.11ah - was introduced. This thesis focuses on implementing a low power receiver design for IoT application. A reconfigurable zero-IF (ZIF)/ low-IF (LIF) architecture is designed to support the 802.11ah specifications. In the implemented SAW-less receiver design, the input RF signal is directly downconverted by mixing operation to baseband frequencies by current-mode passive mixers. The baseband provides the required selectivity and sensitivity of the system. The receiver provides a 24 – 44 dB programmable gain across 1,2,4 MHz bandwidth. It supports an ACR/NACR of 17 dB/32 dB with an overall power consumption of 4 mW at 6 dB NF. The designed receiver is implemented in TSMC 40 nm and is in the fabrication process.

An ASIC is presented for intra-vascular ultrasound imaging. Despite being connected via a single coaxial cable, it is able to pass arbitrary high voltage bipolar signals to the transducers for acoustic imaging. The thesis talks about the need to reduce the cable count to one and reviews the existing work in literature. It builds up on an existing single cable design and focuses on the transmit part to make it compatible to a large number of ultrasound imaging modes by allowing it to pass high frequency signals up to 20MHz and bipolar signal voltages up to ±25V . The chip is phantom powered and thus its power supply and signals are transmitted on the same cable. The transmit switch designed for this ASIC is powered by and controlled by an on-chip low voltage supply and circuitry. The prototype ASIC has been designed in TSMC 180nm HV BCD Gen2 technology. This single cable design has 16 elements for transmit and 64 elements in the receive mode and was evaluated using simulations.

In this report the finger vibrotactile subsystem of the SoftGlove wearable haptic feedback glove is discussed. This system is an upgrade over the vibrotactile feedback that the current SenseGlove haptic feedback glove provides. The designed system consists of a linear resonant actuator (LRA) on each finger, which is controlled by a dedicated LRA driver over I2C. To overcome addressing limitations of the drivers, an I2C switch is used to be able to communicate with each driver individually. The system is characterized both in terms of latency and vibration strength. The peak-to-peak vibration strength is measured to be 1.44 G and a 10 % to 90 % rise and fall time of 44 ms from rest to the maximum vibration strength. Furthermore, the system is integrated with the other subsystems of the SoftGlove on a PCB.

Virtual reality gear is in the early stages of public use. A recent development is the use of haptic feedback gloves to improve immersion. This report describes some of the challenges in this field. The finger force feedback subsystem design of the SoftGlove is discussed including all methods used and measurements done to accomplish an optimal subsystem.

VR gear is in the early stages of public use. A recent development is the use of haptic feedback and gloves to improve the immersion. This reports describes some of the challenges in this field, methods to stream haptic feedback in the form of audio, potential haptic protocols and contains the design process of a haptic feedback glove for SenseGlove.

The information of electrical properties of biological tissues within human body can be useful information for diagnosis, tissue characterization, hyperthermia treatment planning and MR safety control.
CSI-EPT is an MR base imaging modality, which reconstructs the electrical properties of the sample. However, this method have not been implemented in practice due to the following issues:
1) The exact transmit phase is not available from acquisition.
2) The incident field cannot be measured directly.
3) The loss of sensitivity at those regions with low electrical fields.
4) The sufficiency of 2D configuration, which has been used in most published results, have not be verified.
This thesis investigates the experimental feasibility of CSI-EPT through simulations and phantom experiments, implementing a parallel transceive array under two different excitation modes. After which we give answers or improvements to the above issues.

This work presents an ASIC designed to be integrated on the tip of an intra-vascular ultrasound catheter, capable of interfacing 64 ultrasonic transducer elements to an imaging system using only one micro-coaxial cable.
A prototype chip has been taped out that can be used to transmit acoustic waves using a small-area transmit switch. The received echo signal is amplified by a phantom powered LNA and read-out at the other end of the micro-coaxial cable by a transimpedance amplifier.