This research aims at solving an engineering design problem encountered in the field of wireless communication systems using mathematical programming techniques. The problem addressed is an indispensable part of micro-cellular radio system design. It involves an optimal location of radio transmitters, given a distribution of receivers and desired signal characteristics. The study has been conducted with the intent of making this problem an integral part of a CAD system for designing radio communication systems. The tool that has been developed for locating a transmitter in such a context is sensitive to different needs of coverage at different locations in the design space. The physical nature of this problem enables it to be conceptualized as a traditional facility location problem. The transmitter is a service facility responsible for serving all the receivers in the design space. A cost is incurred in terms of path-loss, delay spread, and other separation-based measures, whenever service is extended to a receiver. The objective is to place this transmitter in such a way that it optimally serves all the receivers, as measured according to some merit function. However, the nature of the latter merit or objective function, and the nature of the acceptable region for transmitter placement, imparts a special structure to the problem that distinguishes it from traditional facility location problems. The aim of this research effort is to construct a suitable representative mathematical model for this problem, and to design and compare various solution methodologies that are computationally competitive, numerically stable, and accurate. / Master of Science

This paper introduces a component of the Radio Frequency transceiver called the mixer. The mixer is a critical component in the RF systems, because of its ability for frequency conversion. This passage focuses on the design analysis and simulation of multiple topologies for the active down-conversion mixer. This mixer is characterized by its important design properties which consist of conversion gain, linearity, noise figure, and port isolation. The topologies that are given in this passage range from the most commonly known mixer design, to implemented design techniques that are used to increase the mixers important design properties as the demand of CMOS technology and the overall RF system rises. All mixer topologies were designed and simulated using TSMC 0.18 µm CMOS technology in Advanced Design Systems, a simulator used specifically for RF designs.

The objective of the research presented in this dissertation is to explore the achievable dynamic range limits in high-performance RF front-ends designed using SiGe HBTs, with a focus on complementary (npn + pnp) SiGe technologies. The performance requirements of RF front-ends are high gain, high linearity, low dc power consumption, very low noise figure, and compactness. The research presented in this dissertation shows that all of these requirements can easily be met by using complementary SiGe HBTs. Thus, a strong case is made in favor of using SiGe technologies for designing high dynamic range RF front-ends. The contributions from this research are summarized as follows: 1. The first-ever comparison study and comprehensive analysis of small-signal linearity (IIP3) for npn and pnp SiGe HBTs on SOI. 2. A novel comparison of large-signal robustness of npn and pnp SiGe HBTs for use in high-performance RF front-ends. 3. A systematic and rigorous comparison of SiGe HBT compact models for high-fidelity distortion modeling. 4. The first-ever feasibility study of using weakly-saturated SiGe HBTs for use in severely power constrained RF front-ends. 5. A novel X-band Low Noise Amplifier (LNA) using weakly-saturated SiGe HBTs. 6. Design and comprehensive analysis of RF switches with enhanced large-signal linearity. 7. Development of novel methods to reduce crosstalk noise in mixed-signal circuits and the first-ever analysis of crosstalk noise across temperature. 8. Design of a very high-linearity cellular band quadrature modulator for use in base-station applications using first-generation complementary SiGe HBTs.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Not available / text

SiGe BiCMOS technology has many advantageous properties that, when leveraged, enable circuit design for extreme environments. This work will focus on designs targeted for space system avioinics platforms under the NASA ETDP program. The program specifications include operation under temperatures ranging from -180 C to +125 C and with radiation tolerance up to total ionizing dose of 100 krad with built-in single-event latch-up tolerance. To the author's knowledge, this work presents the first design and measurement of a wide temperature range enabled, radiation tolerant as built, RS-485 wireline transceiver in SiGe BiCMOS technology. This work also includes design and testing of a charge amplification channel front-end intended to act as the interface between a piezoelectric sensor and an ADC. An additional feature is the design and testing of a 50 Ohm output buffer utilized for testing of components in a lab setting.

With the growing demand of compact radio transmitters, so do the need for silent and efficient thermal management systems. Given the restricted form-factor, ensuring robustness of a unit with a detachable fan tray imposes a challenge. In this thesis the authors were tasked with creating a new design solution where the robustness, thermal and noise performance of the cooling system is revised. The project was initiated with an investigation of the baseline product, the AIR5322, to identify areas of in need of improvement. The initial goal was to design an integrated fan tray that would not require in-field maintenance. A literature study was performed to evaluate common integrated cooling solutions in compact electronic devices, which was then followed by concept generation study. These were then ranked based on Pugh’s selection method. An integrated solution was deemed not feasible due to the average lifespan of common fans used in this type of product. A CAD model of said design was created, for which a prototype was manufactured by Ericsson. The final design consisted of a set of 80mm Noctua (NF-A8) fans in a new fan tray, retrofitted onto a modified stock AIR5322 heatsink. Experimental tests were conducted where heat dissipation, noise generation and mechanical robustness was tested. The results concluded that the prototype design managed to reduce the temperature of the entire unit, up to 17°C cooler and lower the sound levels by up to 18 dB. The prototype, despite halving the number of fans, retained the single fan failure redundancy, as running just one fan allowed for performance that was equal to or better than the reference solution at full capacity. The prototype was deemed robust enough to withstand the drop test, which was performed at −18°C. Additional work would include to incorporate fans with an appropriate IP rating and to fully complete the testing using a climate chamber and performing impact testing. / Med den växande efterfrågan på kompakta radiosändare ökar också behovet av tysta och effektiva kylsystem. Givet den begränsade formfaktorn innebär det en utmaning att säkerställa robustheten hos en enhet med en löstagbar fläktlåda. I denna avhandling fick författarna i uppdrag att skapa en ny designlösning där kylsystemets robusthet, termisk prestada och ljudprestanda revideras. Projektet inleddes med en undersökning av basprodukten, AIR5322, för att identifiera eventuella förbättringsområden. Det ursprungliga målet var att designa en integrerad fläktlåda som inte skulle kräva fältetunderhåll. En litteraturstudie genomfördes för att utvärdera vanliga integrerade kyllösningar i kompakta elektroniska enheter, som sedan följdes av konceptgenerering. Dessa utvärderades sedan och rangordnades utifrån Pughs urvalsmetod. En integrerad lösning ansågs inte möjlig på grund av den genomsnittliga livslängden för typiska fläktar som används i liknande produkter. En CAD-modell av denna design skapades, för vilken en prototyp tillverkades av Ericsson. Den slutliga designen bestod av en uppsättning 80 mm Noctua (NF-A8) fläktar i en ny fläktlåda som monterades i en modifierad kylfläns för AIR5322. Experimentella tester där värmeavledning, bullergenerering och mekanisk robusthet testades. Med resultaten kunde följande slutsats dras: prototypdesignen lyckades sänka temperaturen på hela enheten med upp till 17°C och sänka ljudnivåerna med upp till 18 dB. Prototypen visade sig ha en fläkt vara termiskt redundant, eftersom en fläkt igång resulterade i en prestanda som var lika med eller bättre än referenslösningen. Prototypen ansågs vara robust nog att motstå falltestet, som utfördes med prototypen nedkyld til −18°C. Ytterligare arbete som kan vara till nytta för detta projekt skulle vara att införliva fläktar med en lämplig IP-klassning och att fullständigt testa prototypen med klimattester och slagtester.

The communication industry leverages technical advancements in various domains, such as semiconductors, optics, signal processing, and integrated circuits, leading to remarkable evolution over the last decades. This progress paves the way for ever-expanding networks and systems that demand more information capacity, which results in exponential data growth. Unique wireless concepts and technologies are emerging to enable next-generation communication. This dissertation explores the techniques and architectures to realize massive MIMO, extreme bandwidths through channel aggregation, TeraHertz band utilization, and the use of III-V technologies to enhance performance via heterogeneous integration, ultimately maintaining ubiquitous connectivity. The first chapter discusses the various recent research trends in communication technologies: the allocation of millimeter-wave frequencies to benefit from the broad available spectrum, 2D scalability to enhance system performance and overcome link budget requirements, MIMO, and channel aggregation concepts to extend data capacity, heterogeneous integration to exploit benefits of various technologies, transitioning to THz region to improve spectrum efficiencies and diversify applications. The key insight of this dissertation is that we implement distinct system/architecture-level solutions to achieve target data rates for the continuation of the advancements in communication technologies. The first project in this thesis presents a MIMO receiver array that utilizes a simplified single-wire interface for IF/LO signals that overcomes the high-frequency input/output distribution complexity for large-scale systems. Code-domain multiplexing is performed on the single-wire interface to preserve and transfer individual information of all channels. The four-channel receiver prototype that operates at 28GHz and achieves >20dB channel-to-channel isolation is presented. Digital beamforming and MIMO capability of the array have been demonstrated. The later chapter of this dissertation discusses the fundamental limitation of code-domain multiplexing, the trade-off between isolation and interface bandwidth, and explains our novel frequency-domain multiplexing approach. A harmonic rejection mixer has been used to generate the required multiple LO tones to de-multiplex individual channel signals simultaneously. A 60GHz four-element MIMO transmitter prototype is presented, and its functionalities are illus- trated. The prototype achieves >30dB channel-to-channel isolation for an overall bandwidth of 10GHz, supports 64QAM modulated signals, and is capable of performing MIMO beamforming. Next, benefiting from our research experience on FDM and HRM, we proposed a frequency- interleaving architecture for wideband channel aggregated systems. We divided the total IF band- width into four sub-channels and individually up/down-converted them to the baseband, alleviating the requirements of Analog-to-Digital/Digital-to-Analog Converters. HRM is utilized to generate multiple LO frequencies, as in the FDM-based transmitter work. The prototype system comprises two baseband channelizer ICs (TX/RX) and two mm-wave beamformer ICs (TX/RX), where channelizers perform FI aggregation and despread IF signals, and beamformers are responsible for beam steering and tapering. The four-channel transceiver chipset operates at 60GHz, provides >25dB isolation for an overall IF bandwidth of 8GHz, and supports 64QAM modulated signals. The next section of the dissertation presents a wideband sub-THz transceiver phased array system with SWI. We propose a D-band scalable 16-element transceiver system with novel front- end block designs to satisfy link budget requirements and enable high data rates and complex modulation data transfer. The prototype consists of one phased array transmitter and one phased array receiver. Simulated performance shows that the receiver system has ∼34dB gain, -30dBmIP1dB with a minimum 5.4dB NF. While, transmitter achieves ∼34dB gain with a 9dBm OP1dB. The last chapter looks beyond CMOS technology and presents front-end blocks at III-V technologies. Two circulator prototype designs with different architectures are implemented using GaN technology. Better linearity performance is targeted by leveraging heterogeneous integration, using GaN devices for the core and CMOS circuitry for clock generation. In addition, a future direction for THz systems, GaN-assisted beamformer architecture, is presented.

Time Average Fourier Telescopy (TAFT) has been proposed as a means for obtaining high-resolution, diffraction-limited images over large distances through ground-level horizontal-path atmospheric turbulence. Image data is collected in the spatial-frequency, or Fourier, domain by means of Fourier Telescopy; an inverse two dimensional Fourier transform yields the actual image. TAFT requires active illumination of the distant object by moving interference fringe patterns. Light reflected from the object is collected by a “light-bucket” detector, and the resulting electrical signal is digitized and subjected to a series of signal processing operations, including an all-critical averaging of the amplitude and phase of a number of narrow-band signals. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

The development of multi-standard wireless communication systems with low cost and high integration is continuously requested and accompanied by the explosive growth of the wireless communication market. Although CMOS technology can provide most building blocks in RF transceivers, the implementation of CMOS RF power amplifiers is still a challenging task. The objective of this research is to develop design techniques to implement fully-integrated multi-mode power amplifiers using CMOS technology. In this dissertation, a load modulation technique with tunable matching networks and a pre-distortion technique in a multi-stage PA are proposed to support multi-communication standards with a single PA. A fully-integrated dual-mode GSM/EDGE PA was designed and implemented in a 0.18 um CMOS technology to achieve high output power for the GSM application and high linearity for the EDGE application. With the suggested power amplifier design techniques, fully-integrated PAs have been successfully demonstrated in GSM and EDGE applications. In Addition to the proposed techniques, a body-switched cascode PA core is also proposed to utilize a single PA in multi-mode applications without hurting the performance. With the proposed techniques, a fully-integrated multi-mode PA has been implemented in a 0.18 um CMOS technology, and the power amplifier has been demonstrated successfully for GSM/EDGE/WCDMA applications. In conclusion, the research in this dissertation provides CMOS RF power amplifier solutions for multiple standards in mobile wireless communications with low cost and high integration.