Application of advanced on-board processing concepts to future satellite communications systems

An initial definition of on-board processing requirements for an advanced satellite communications system to service domestic markets in the 1990's is presented. An exemplar system architecture with both RF on-board switching and demodulation/remodulation baseband processing was used to identify important issues related to system implementation, cost, and technology development

Analysis and Design of a Sub-THz Ultra-Wideband Phased-Array Transmitter

This thesis investigates circuits and systems for broadband high datarate transmitter systems in the millimeter-wave (mm-wave) spectrum. During the course of this dissertation, the design process and characterization of a power efficient and wideband binary phase-shift keying (BPSK) transmitter integrated circuit (IC) with local oscillator (LO) frequency multiplication and 360° phase control for beam steering is studied. All required circuit blocks are designed based on the theoretical analysis of the underlying principles, optimized, fabricated and characterized in the research laboratory targeting low power consumption, high efficiency and broadband operation. The phase-controlled push-push (PCPP) architecture enabling frequency multiplication by four in a single stage is analytically studied and characterized finding an optimum between output power and second harmonic suppression depending on the input amplitude. A PCPP based LO chain is designed. A circuit is fabricated establishing the feasibility of this architecture for operation at more than 200 GHz. Building on this, a second circuit is designed, which produces among the highest saturated output powers at 2 dBm. At less than 100 mW of direct current (DC) power consumption, this results in a power-added efficiency (PAE) of 1.6 % improving the state of the art by almost 30 %. Phase-delayed and time-delayed approaches to beam steering are analyzed, identifying and discussing design challenges like area consumption, signal attenuation and beam squint. A 60 GHz active vector-sum phase-shifter with high gain of 11.3 dB and output power of 5 dBm, improving the PAE of the state of the art by a factor of 30 achieving 6.29 %, is designed. The high gain is possible due to an optimization of the orthogonal signal creation stage enabled by studying and comparing different architectures leading to a trade off of lower signal attenuation for higher area consumption in the chosen electromagnetic coupler. By combining this with a frequency quadrupler, a phase steering enabled LO chain for operation at 220 GHz is created and characterized, confirming the preceding analysis of the phase-frequency relation during multiplication. It achieves a power gain of 21 dB, outperforming comparable designs by 25 dB. This allows the combination of phase control, frequency multiplication and pre-amplification. The radio frequency (RF) efficiency is increased 40-fold to 0.99 %, with a total power consumption of 105 mW. Motivated by the distorting effect of beam squint in phase-delayed broadband array systems, a novel analog hybrid beam steering architecture is devised, combining phase-delayed and time-delayed steering with the goal of reducing the beam squint of phase-delayed systems and large area consumption of time-delayed circuits. An analytical design procedure is presented leading to the research finding of a beam squint reduction potential of more than 83 % in an ideal system. Here, the increase in area consumption is outweighed by the reduction in beam squint. An IC with a low power consumption of 4.3 mW has been fabricated and characterized featuring the first time delay circuit operating at above 200 GHz. By producing most of the beam direction by means of time delay the beam squinting can be reduced by more than 75 % in measurements while the subsequent phase shifter ensures continuous beam direction control. Together, the required silicon area can be reduced to 43 % compared to timedelayed systems in the same frequency range. Based on studies of the optimum signal feeding and input matching of a Gilbert cell, an ultra-wideband, low-power mixer was designed. A bandwidth of more than 100 GHz was achieved exceeding the state of the art by 23 %. With a conversion gain of –13 dB, this enables datarates of more than 100 Gbps in BPSK operation. The findings are consolidated in an integrated transmitter operating around 246 GHz doubling the highest published measured datarates of transmitters with LO chain and power amplifier in BPSK operation to 56 Gbps. The resulting transmitter efficiency of 7.4 pJ/bit improves the state of the art by 70 % and 50 % over BPSK and quadrature phaseshift keying (QPSK) systems, respectively. Together, the results of this work form the basis for low-power and efficient next-generation wireless applications operating at many times the datarates available today.:Abstract 3 Zusammenfassung 5 List of Symbols 11 List of Acronyms 17 Prior Publications 19 1. Introduction 21 1.1. Motivation........................... 21 1.2. Objective of this Thesis ................... 25 1.3. Structure of this Thesis ................... 27 2. Overview of Employed Technologies and Techniques 29 2.1. IntegratedCircuitTechnology................ 29 2.2. Transmission Lines and Passive Structures . . . . . . . . 35 2.3. DigitalModulation ...................... 41 3. Frequency Quadrupler 45 3.1. Theoretical Analysis of Frequency Multiplication Circuits 45 3.2. Phase-Controlled Push-Push Principle for Frequency Quadrupling.......................... 49 3.3. Stand-alone Phase-Controlled Push-Push Quadrupler . 60 3.4. Phase-Controlled Push-Push Quadrupler based LO-chain with High Output Power ............... 72 9 4. Array Systems and Dynamic Beam Steering 91 4.1. Theoretical Analysis of BeamSteering. . . . . . . . . . . 95 4.2. Local Oscillator Phase Shifting with Vector-Modulator PhaseShifters......................... 107 4.3. Hybrid True-Time and Phase-Delayed Beam Steering . 131 5. Ultra-Wide Band Modulator for BPSK Operation 155 6. Broadband BPSK Transmitter System for Datarates up to 56 Gbps 167 6.1. System Architecture ..................... 168 6.2. Measurement Technique and Results . . . . . . . . . . . 171 6.3. Summary and performance comparison . . . . . . . . . 185 7. Conclusion and Outlook 189 A. Appendix 195 Bibliography 199 List of Figures 227 Note of Thanks 239 Curriculum Vitae 241Diese Dissertation untersucht Schaltungen und Systeme für breitbandige Transmittersysteme mit hoher Datenrate im Millimeterwellen (mm-wave) Spektrum. Im Rahmen dieser Arbeit werden der Entwurfsprozess und die Charakterisierung eines leistungseffizienten und breitbandigen integrierten Senders basierend auf binärer Phasenumtastung (BPSK) mit Frequenzvervielfachung des Lokaloszillatorsignals und 360°-Phasenkontrolle zur Strahlsteuerung untersucht. Alle erforderlichen Schaltungsblöcke werden auf Grundlage von theoretischen Analysen der zugrundeliegenden Prinzipien entworfen, optimiert, hergestellt und im Forschungslabor charakterisiert, mit den Zielen einer niedrigen Leistungsaufnahme, eines hohen Wirkungsgrades und einer möglichst großen Bandbreite. Die phasengesteuerte Push-Push (PCPP)-Architektur, welche eine Frequenzvervierfachung in einer einzigen Stufe ermöglicht, wird analytisch untersucht und charakterisiert. Dabei wird ein Optimum zwischen Ausgangsleistung und Unterdrückung der zweiten Harmonischen des Eingangssignals in Abhängigkeit von der Eingangsamplitude gefunden. Es wird eine LO-Kette auf PCPP-Basis entworfen. Eine Schaltung wird präsentiert, die die Machbarkeit dieser Architektur für den Betrieb bei mehr als 200 GHz nachweist. Darauf aufbauend wird eine zweite Schaltung entworfen, die mit 2 dBm eine der höchsten publizierten gesättigten Ausgangsleistungen erzeugt. Mit einer Leistungsaufnahme von weniger als 100mW ergibt sich ein Leistungswirkungsgrad (PAE) von 1.6 %, was den Stand der Technik um fast 30 % verbessert. Es werden phasenverzögerte und zeitverzögerte Ansätze zur Steuerung der Strahlrichtung analysiert, wobei Entwicklungsherausforderungen wie Flächenverbrauch, Signaldämpfung und Strahlschielen identifiziert und diskutiert werden. Ein aktiver Vektorsummen-Phasenschieber mit hoher Verstärkung von 11.3 dB und einer Ausgangsleistung von 5 dBm, der mit einer PAE von 6.29 % den Stand der Technik um den Faktor 30 verbessert, wird entworfen. Die hohe Verstärkung ist zum Teil auf eine Optimierung der orthogonalen Signalerzeugungsstufe zurückzuführen, die durch die Untersuchung und den Vergleich verschiedener Architekturen ermöglicht wird. Bei der Entscheidung für einen elektromagnetischen Koppler rechtfertigt die geringere Signaldämpfung einen höheren Flächenverbrauch. Durch die Kombination mit einem Frequenzvervierfacher wird eine LO-Kette mit Phasensteuerung für den Betrieb bei 220 GHz geschaffen und charakterisiert, was die vorangegangene Analyse der Phasen-FrequenzBeziehung während der Multiplikation bestätigt. Sie erreicht einen Leistungsgewinn von 21 dB und übertrifft damit vergleichbare Designs um 25dB. Dies ermöglicht die Kombination von Phasensteuerung, Frequenzvervielfachung und Vorverstärkung. Der HochfrequenzWirkungsgrad wird um das 40-fache auf 0.99 % bei einer Gesamtleistungsaufnahme von 105 mW gesteigert. Motiviert durch den verzerrenden Effekt des Strahlenschielens in phasengesteuerten Breitbandarraysystemen, wird eine neuartige analoge hybride Strahlsteuerungsarchitektur untersucht, die phasenverzögerte und zeitverzögerte Steuerung kombiniert. Damit wird sowohl das Strahlenschielen phasenverzögerter Systeme als auch der große Flächenverbrauch zeitverzögerter Schaltungen reduziert. Es wird ein analytisches Entwurfsverfahren vorgestellt, das zu dem Forschungsergebnis führt, dass in einem idealen System ein Potenzial zur Reduktion des Strahlenschielens von mehr als 83 % besteht. Dabei wird die Zunahme des Flächenverbrauchs durch die Verringerung des Strahlenschielens aufgewogen. Es wird ein IC mit einer geringen Leistungsaufnahme von 4.3mW hergestellt und charakterisiert. Dabei wird die erste Zeitverzögerungsschaltung entworfen, die bei über 200 GHz arbeitet. Durch die Erzeugung eines Großteils der Strahlrichtung mittels Zeitverzögerung kann das Schielen des Strahls bei Messungen um mehr als 75% reduziert werden, während der nachfolgende Phasenschieber eine kontinuierliche Steuerung der Strahlrichtung gewährleistet. Insgesamt kann die benötigte Siliziumfläche im Vergleich zu zeitverzögerten Systemen im gleichen Frequenzbereich auf 43 % reduziert werden. Auf der Grundlage von Studien zur optimalen Signaleinspeisung und Eingangsanpassung einer Gilbert-Zelle wird ein Ultrabreitband-Mischer mit geringem Stromverbrauch entworfen. Dieser erreicht eine Ausgangsbandbreite von mehr als 100 GHz, die den Stand der Technik um 23% übertrifft. Bei einer Wandlungsverstärkung von –13dB ermöglicht dies Datenraten von mehr als 100 Gbps im BPSK-Betrieb. Die Erkenntnisse werden in einem integrierten, breitbandigen Sender konsolidiert, der um 246 GHz arbeitet und die höchsten veröffentlichten gemessenen Datenraten für Sender mit LO-Signalkette und Leistungsverstärker im BPSK-Betrieb auf 56 Gbps verdoppelt. Die daraus resultierende Transmitter-Effizienz von 7.4 pJ/bit verbessert den Stand der Technik um 70 % bzw. 50 % gegenüber BPSKund Quadratur Phasenumtastung (QPSK)-Systemen. Zusammen bilden die Ergebnisse dieser Arbeit die Grundlage für stromsparende, effiziente, mobile Funkanwendungen der nächsten Generation mit einem Vielfachen der heute verfügbaren Datenraten.:Abstract 3 Zusammenfassung 5 List of Symbols 11 List of Acronyms 17 Prior Publications 19 1. Introduction 21 1.1. Motivation........................... 21 1.2. Objective of this Thesis ................... 25 1.3. Structure of this Thesis ................... 27 2. Overview of Employed Technologies and Techniques 29 2.1. IntegratedCircuitTechnology................ 29 2.2. Transmission Lines and Passive Structures . . . . . . . . 35 2.3. DigitalModulation ...................... 41 3. Frequency Quadrupler 45 3.1. Theoretical Analysis of Frequency Multiplication Circuits 45 3.2. Phase-Controlled Push-Push Principle for Frequency Quadrupling.......................... 49 3.3. Stand-alone Phase-Controlled Push-Push Quadrupler . 60 3.4. Phase-Controlled Push-Push Quadrupler based LO-chain with High Output Power ............... 72 9 4. Array Systems and Dynamic Beam Steering 91 4.1. Theoretical Analysis of BeamSteering. . . . . . . . . . . 95 4.2. Local Oscillator Phase Shifting with Vector-Modulator PhaseShifters......................... 107 4.3. Hybrid True-Time and Phase-Delayed Beam Steering . 131 5. Ultra-Wide Band Modulator for BPSK Operation 155 6. Broadband BPSK Transmitter System for Datarates up to 56 Gbps 167 6.1. System Architecture ..................... 168 6.2. Measurement Technique and Results . . . . . . . . . . . 171 6.3. Summary and performance comparison . . . . . . . . . 185 7. Conclusion and Outlook 189 A. Appendix 195 Bibliography 199 List of Figures 227 Note of Thanks 239 Curriculum Vitae 24

High-speed optical data transmission for detector instrumentation in particle physics

This work discusses the advantage of optical transmission utilizing wavelength-division multiplexing for the read-out of experimental data in detector instrumentation in high-energy physics, astroparticle physics or photon science. A multi-channel optical transmitter is developed as the core component on a silicon-on-insulator platform. It implements Mach-Zehnder modulators with a depletion-type pn-phase shifter in each arm, while the (de )multiplexers rely on planar concave gratings. The modulator design is expected to support a symbol rate in the range 40 GBd even with a phase shifter length of 3 mm. The development of an efficient simulation method is presented, which allows for the reliable prediction of the steady-state modulator characteristics. Furthermore, this work addresses the packaging technology for grating-coupled silicon photonic components. In particular, a fabrication and assembly process for a planar fiber-to-chip coupling using angle-polished single-mode fibers is developed. A long-term-stable coupling with a small footprint is achieved, of which the coupling efficiency is only weakly dependent on ambient conditions

Vaiheensiirtimien integrointi aaltoputkiohjattuun antenniryhmään

In this master’s thesis, phase shifter integration for the future 5G base station antennas is studied using electromagnetic simulations and measurements. The integration is done for two antenna prototypes, which operate at 71–86 GHz band (E-band) and 26–30 GHz band (cm-band), respectively. The base station antenna is a waveguide-fed phased array and the phase shifters are integrated on a PCB, which is installed between the feeding network and a horn antenna array. Two waveguide-to-microstrip transitions are designed and simulated for both frequency bands. The average insertion losses of the transitions are 0.7 dB at E-band, and 0.35 dB at cm-band, confirming suitability for the antenna prototypes. A sensitivity analysis of the main transition parameters suggests that manufacturing precision should be ±30 µm at E-band and ±50 µm at cm-band, respectively. Fixed microstrip line-based true time delay phase shifters are designed for E-band. Their performance is validated by simulations and measurements. The results show that the phase shifters have full 360°phase shift range for the beam-steering demonstration of the prototype antenna. TGP2100 phase shifters from TriQuint are used for cm-band. A test structure is fabricated and measured to characterize the phase shifter but it is damaged during the phase shifter installation. Other test structures are designed and measured to evaluate losses due to wire bonding of the phase shifter to the PCB. The measurement results show the insertion loss from the wire bonding is around 4 dB. Also, a phase shifter test structure made by Nokia Bell Labs is simulated and measured. The results show that the used phase shifter simulation model does not predict the phase shifter performance correctly when the RF-grounding is defected e.g. due to unsuitable glue or solder. The simulations indicate that the main source of antenna prototype transmission losses are the phase shifters. Still, the phase shifters are suitable for the beam-steering demonstration. Future work includes fabricating the final antenna prototype for the cm-band and its measurements.Tässä diplomityössä on tutkittu vaiheensiirtimien integrointia tulevaisuuden 5G tukiasema-antenneihin käyttäen apuna sähkömagneettisia simulaatioita ja mittauksia. Integrointi on toteutettu kahdelle antenniprototyypille, jotka toimivat 71–86 GHz (E-kaista) ja 26–30 GHz (cm-kaista) taajuuksilla. Tukiasema-antenni on aaltoputkilla syötetty, vaiheohjattu antenniryhmä ja vaiheensiirtimet integroidaan piirilevylle, joka asennetaan syöttöverkon ja torviantenniryhmän väliin. Kaksi aaltoputki-mikroliuska-siirtymää on suunniteltu ja simuloitu molemmille taajuuskaistoille. Simulaatiotulokset osoittavat, että siirtymillä on pienet keskimääräiset väliinkytkemisvaimennukset: 0,7 dB E-kaistalla ja 0,35 dB cm-kaistalla, joten ne sopivat käytettäväksi antenniprototyypeissä. Siirtymän tärkeimmistä mitoista tehty herkkyysanalyysi osoittaa että ±30 µm valmistustarkkuus on riittävä E-kaistalle ja ±50 µm valmistustarkkuus cm-kaistalle. Kiinteät mikroliuskapohjaiset vaiheensiirtimet on suunniteltu E-kaistalle. Niiden toiminnallisuus on varmistettu simuloinneilla ja mittauksilla. Tulokset osoittavat, että vaiheensiirtimillä voidaan toteuttaa 360°:een vaiheensiirto ja ne sopivat käytettäväksi prototyyppiantennin vaiheistamiseen. TriQuintin valmistamia TGP2100-vaiheensiirtimiä käytetään cm-kaistalla. Testirakenne valmistettiin vaiheensiirtimen karakterisointia varten, mutta testialustalle asennetun vaiheensiirtimen havaittiin olevan vahingoittunut. Muita testirakenteita on suunniteltu ja mitattu vaiheensiirtimen lankabondauksesta johtuvien häviöiden selvittämiseksi: lankabondauksesta aiheutuu noin 4 dB:n häviöt. Lisäksi Nokia Bell Labsin valmistama testirakenne on simuloitu ja mitattu. Tuloksista nähdään, että vaiheensiirtimen simulaatiomalli ei toimi oletetulla tavalla, jos vaiheensiirtimen RF-maadoitus on viallinen. Tämä voi johtua esimerkiksi sopimattomasta liimasta tai juotteesta. Simulaatiot osoittavat, että vaiheensiirtimet ovat antenniprototyyppien pääasiallinen siirtohäviölähde, mutta ne sopivat antennin vaiheistamisen esittelyyn. Tutkimusta aiotaan jatkaa valmistamalla antenniprototyyppi cm-kaistalle ja mittaamalla sen toiminta

DESIGN OF A GAAS DISTRIBUTED AMPLIFIER WITH LC TRAPS BASED BROADBAND LINEARIZATION

Increasing the linearity of power amplifiers has been an important area of research because its signal integrity influences the performance of the entire transreceiver system and there are strict regulatory requirements on them. Due to the nonlinear behaviour of power amplifiers, third order intermodulation products are generated close to the desired signals and cannot be removed by filters. Increasing linearity will help bring these distortion products closer to the noise floor. However, it is not an easy task to increase linearity without trading off output power. To maintain the same level of output power generated but with higher linearity, many techniques, each with its own pros and cons, have been implemented to linearize an amplifier. Techniques involving feedback are seriously limited in terms of modulation bandwidth whereas methods such as predistortion and feedforward are very difficult to implement. This project seeks to use a simple method of placing terminations directly to the distributed amplifier (DA), making it a device level linearization technique and can be used in addition to the other system level techniques mentioned earlier. To increase linearity over a broad bandwidth of 0.5 to 3.0 GHz, this work proposes using low impedance terminations (LC traps) at the envelope frequency to the input and output of several distributed amplifiers. This research is novel since this is the first time broadband improvement in linearity has been demonstrated using the LC trap method. Two design iterations were completed (first design iteration has four variants to test the output trap while the second design iteration has three variants to test the input trap). The low impedance terminations are implemented using inductor-capacitor networks that are external to the monolithic microwave integrated circuit (MMIC). Design and layout of the DAs were carried out using Agilent’s Advanced Design System (ADS). Results show that placing the traps at the output of the DA does not truly affect the linearity of the device at lower frequencies but provide an improvement of 1.6 dB and 3.4 dB to the third-order output intercept point (OIP3) at 2.5 GHz and 3.0 GHz, respectively. With traps at the input, measurement results at -5 dBm input power, viii 1.375 V base bias (61 mA total collector current) and 10 MHz two tone spacing show a broadband improvement throughout the band (0.5 GHz to 3.0 GHz) of 3.3 dB to 7.4 dB in OIP3. Furthermore, the OIP3 is increased to 19.2 dB above P1dB. Results show that the improvement in OIP3 comes without lowering gain, return loss or P1dB and without causing any stability problems

A 5 GHz BiCMOS I/Q VCO with 360° variable phase outputs using the vector sum method

This research looks into the design of an integrated in-phase/quadrature (I/Q) VCO operating at 5 GHz. The goal is to design a phase shifter that is implemented at the LO used for RF up conversion. The target application for the phase shifter is towards phased array antennas operating at 5 GHz. Instead of designing multiple VCOs that each deliver a variety of phases, two identical LC-VCOs are coupled together to oscillate at the same frequency and deliver four outputs that are 90 ° out of phase. By varying the amplitudes of the in-phase and quadrature signals independently using VGAs before adding them together, a resultant out-of-phase signal is obtained. A number of independently variable out-of-phase signals can be obtained from these 90 ° out-of-phase signals and this technique is better known as the vector sum method of phase shifting. Control signals to the inputs of the VGAs required to obtain 22.5 ° phase shifts were designed from simulations and are generated using 16-bit DACs. The design is implemented and manufactured using a 0.35 µm SiGe BiCMOS process and the complete prototype IC occupies an area of 2.65 × 2.65 mm2. The I/Q VCO with 360 ° variable phase outputs occupies 1.10 × 0.85 mm2 of chip area and the 16-bit DAC along with its decoding circuitry occupies 0.41 × 0.13 mm2 of chip area. The manufactured quadrature VCO was found to oscillate between 4.12 ~ 4.74 GHz and consumes 23.1 mW from a 3.3 V supply without its buffer circuitry. A maximum phase noise of -78.5 dBc / Hz at a 100 kHz offset and -108.17 dBc / Hz at a 1 MHz offset was measured and the minimum VCO figure of merit is 157.8 dBc / Hz. The output voltages of the 16 bit DAC are within 3.5 % of the design specifications. When the phase shifter is controlled by the 16 DAC signals, the maximum measured phase error of the phase shifter is lower than 10 %.Dissertation (MEng)--University of Pretoria, 2009.Electrical, Electronic and Computer Engineeringunrestricte