A COMPREHENSIVE OVERVIEW OF RECENT DEVELOPMENTS IN RF-MEMS TECHNOLOGY-BASED HIGH-PERFORMANCE PASSIVE COMPONENTS FOR APPLICATIONS IN THE 5G AND FUTURE TELECOMMUNICATIONS SCENARIOS

The goal of this work is to provide an overview about the current development of radio-frequency microelectromechanical systems technology, with special attention towards those passive components bearing significant application potential in the currently developing 5G paradigm. Due to the required capabilities of such communication standard in terms of high data rates, extended allocated spectrum, use of massive MIMO (Multiple-Input-Multiple-Output) systems, beam steering and beam forming, the focus will be on devices like switches, phase shifters, attenuators, filters, and their packaging/integration. For each of the previous topics, several valuable contributions appeared in the last decade, underlining the improvements produced in the state of the art and the chance for RF-MEMS technology to play a prominent role in the actual implementation of the 5G infrastructure

Impedance Transformers

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A Review of Multimaterial Additively Manufactured Electronics and 4-D Printing/Origami Shape-Memory Devices: Design, Fabrication, and Implementation

Emerging additive manufacturing (AM) technologies, specifically additively manufactured electronics (AME), 4-D printing, and origami, are reshaping the design capabilities and functionalities of contemporary electronic devices. Cutting-edge 3-D/4-D printing technologies facilitate the prototyping and realization of complex electronic functions that are challenging to conventional methods. This article provides a comprehensive overview of the evolving techniques in AME, 4-D printing, and origami, employing multimaterials (conductive and dielectric materials) and shape-memory materials (SMMs) to fabricate functional electronic components and devices. Additionally, the overview delves into the state-of-the-art AME and 4-D-printed electronic components across diverse fields, including biomedical electronics, space engineering, and the advancements in the next-generation wireless communications and sensing

The Next Generation Balloon-Borne Large Aperture Submillimeter Telescope (blast-Tng)

Large areas of astrophysics, such as precision cosmology, have benefited greatly from large maps and datasets, yielded by telescopes of ever-increasing number and ability. However, due to the unique challenges posed by submillimeter polarimetry, the study of molecular cloud dynamics and star formation remain stunted. Previously, polarimetry data was limited to a few vectors on only the brightest areas of molecular clouds. This made drawing statistically-driven conclusions a daunting task. However, the successful flight of the Balloon-born Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) generated maps with thousands of independent polarization measurements of molecular clouds, and ushered in a new era of empirical modeling of molecular cloud dynamics. Now that the potential benefits from large-scale maps of magnetic fields in molecular clouds had been identified, a successor that would truly unlock the secrets must be born. The Next Generation Balloon-borne Large Aperture Submillimeter Telescope (BLAST-TNG), the successor to BLASTPol, has the ability to make larger and more detailed maps of magnetic fields in molecular clouds. It will push the field of star formation into a statistics-driven, empirical realm. With these large, detailed datasets, astronomers will be able to find new relationships between the dust dynamics and the magnetic fields. The field will surge to a new level of understanding. One of the key enabling technologies of BLAST-TNG is its three arrays of polarization-sensitive Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are superconducting RLC circuits with a resonant frequency that shifts proportionally to the amount of incident radiation. The key feature of MKIDs is that thousands of detectors, each with their own unique resonant frequency, can be coupled to the same readout line. This technology will be able to drive the production of large-scale monolithic arrays, containing tens or hundreds of thousands of detectors, resulting in an ever-increasing rate of scientific progress. The current limiting factor that determines how many MKIDs can be placed on the same readout line is the bandwidth and processing limitations of the readout hardware. BLAST-TNG has pushed this technology forward by implementing the first Reconfigurable Open-Architecture Computing Hardware (ROACH2) based readout system. This has significantly raised the processing abilities of the MKID readout electronics, enabling over 1000 MKIDs to be read out on a single line. It is also the first ever ROACH (1 or 2) based system to ever be flown on a long duration balloon (LDB) payload. This thesis documents the first-ever deployment of MKIDs on a balloon payload. This is a significant technological step towards an MKID-based satellite payload. This thesis overviews the balloon payload, details the underlying detector physics, catalogs the detector and full-scale array development, and ends with the room-temperature readout electronics

Design and fabrication of suspended-gate MOSFETs for MEMS resonator, switch and memory applications

Wireless communication systems and handset devices are showing a rapid growth in consumer and military applications. Applications using wireless communication standards such as personal connectivity devices (Bluetooth), mobile systems (GSM, UMTS, WCDMA) and wireless sensor network are the opportunities and challenges for the semi-conductor industry. The trend towards size and weight reduction, low power consumption and increased functionalities induces major technological issues. Today, the wireless circuit size is limited by the use of lots of external or "off-chip" components. Among them, quartz crystal, used as the time reference in any wireless systems, is the bottleneck of the miniaturization. Microelectromechanical systems (MEMS) is an emerging technology which has the capability of replacing the quartz. Based on similar technology than the Integrated Circuit (IC), MEMS are referred as electrostatically, thermally or piezoelectrically actuated mechanical structures. In this thesis, a new MEMS device based on the hybridization of a mechanical vibrating structure and a solid-sate MOS transistor has been developed. The Resonant Suspended-Gate MOSFET (RSG-MOSFET) device combines both advantages of a high mechanical quality factor and the transistor intrinsic gain. The physical mechanisms behind the actuation and the behavior of this device were deeply investigated and a quasi-static model was developed and validated, based on measured characteristics. Furthermore, the dynamic model of the RSG-MOSFET was created, taking into account the non-linear mechanical vibrations of the gate and the EKV model, used for MOSFET modeling. Two fabrication processes were successfully developed to demonstrate the proof of concept of such a device and to optimize the performances respectively. Aluminum-silicon (Al-Si1%) and pure silicon-based RSG-MOSFETs were successfully fabricated. DC and AC characterizations on both devices enabled to understand, extract and evaluate the mechanical and MOSFET effects. A specifically developed RF characterization methodology was used to measure the linear and non-linear behaviors of the resonator and to evaluate the influence of each polarization voltages on the signal response. RSG-MOSFET with resonant frequencies ranging from 5MHz to 90MHz and quality factor up to 1200 were measured. Since MEMS resonator quality factor is strongly degraded by air damping, a 0-level thin film vacuum packaging (10-7 mBar) process was developed, compatible with both AlSi-based and silicon-based RSG-MOSFET. The technology has the unique advantage of being done on already released structure and the room temperature process makes it suitable for above-IC integration. In parallel, a front-end compatible process was defined and major build blocks were developed in industrial environment at STMicroelectronics. This technology is based on the Silicon-On-Nothing technology, originally developed for advanced transistor, and therefore making the MEMS resonator process compatible with CMOS co-integration. DC characterizations of SG-MOSFET had shown interesting performances of this device for current switch and memory applications. Mechanical contact of the gate with the MOSFET channel induces a current switching slope greater than 0.8mV/decade, much better than the theoretical MOSFET limit of 60mV/decade. Maximum switch isolations of -37dB at 2 GHz and -27dB at 10GHz were measured on these devices. A novel MEMS-memory has been demonstrated, based on the direct charge injection to the storage media by the mechanical contact of the metal gate. Charge injection and retention mechanisms were investigated based on measured devices. Cycling study of up to 105 cycles were performed without noticing major degradations of the electrical behavior neither mechanical fatigue of the suspended gate. The measured retention time places this memory in between the DRAM and the FLASH memories. A scaling study has shown integration and compatibilities capabilities with existing CMOS

Dynamics of Water Movement near Boundaries of the Vadose Zone

Processes at boundaries of the unsaturated soil water zone were investigated: At the upper boundary evaporation at the soil-atmosphere interface, and at the lower boundary the dynamic capillary fringe. For studying the upper boundary, an evaporation experiment at the representative elementary volume (REV) scale was considered and modelled numerically. A model with a diffusive boundary layer and a 1D Richards' description including vapour transport fitted well to experimental data. It showed a boundary layer dominated regime in the wet range and a regime where dynamics is controlled by soil hydraulic properties in the dry range. The model could successfully be used to determine soil hydraulic properties from the corresponding evaporation experiment by inverse modelling using a Monte-Carlo Levenberg-Marquardt approach. For the lower boundary, light transmission and NIR imaging spectroscopy methods were developed and employed to measure the micro- and macroscopic water distribution in response to transient boundary conditions in a semi-2D sand medium in a Hele-Shaw cell with high temporal and spacial resolution. The analysis showed that coupled multi-phase and dynamic non-equillibrium effects are essential to understand water movement in dynamic capillary fringes, and sub-REV processes play an important role in the dynamics

Controlling Terahertz Radiation - Novel Fabrication Methods and Materials for Terahertz Components

The interaction between light and matter has been a field of research for centuries, from the days of Sir Isaac Newton in the 17th century up to today, where new effects, such as plasmonics open up new applications or the extension of the accessible electromagnetic spectrum, are still engaging scientists and engineers in this field of research. The understanding of the interaction between light, or more general: electromagnetic radiation and matter is a crucial step in the development of components which give the necessary control to gain access to the desired part of the electromagnetic spectrum. One of the less developed parts of the electromagnetic spectrum is terahertz (THz) radiation. THz radiation promises many applications, from spectroscopy for material and medical applications to communication technology. But, so far, most applications have not managed to overcome the experimental status, mostly because of missing materials and manufacturing methods suitable for the required length scales and material properties in the terahertz regime. This thesis focuses on structures for the control of THz radiation. To do so, and to overcome the natural limitations of many materials in the THz region, new materials and modern fabrication techniques are used to find new ways to overcome the shortage of readily available components for this part of the electromagnetic spectrum. As such, ceramics and polymers are used for various components, from lenses to spoof plasmonic waveguides, fabricated with a variety of techniques, including 3D printing and micro-milling. Finite-Difference Time-Domain simulations are used for the design of all structures. The ultimate goal is to demonstrate low-cost methods to produce THz components for future industrial implementation