60 GHz transceiver circuits in SiGe-HBT and CMOS technologies

Die Erhöhung der Übertragungsrate von Kommunikationssystemen ist von hohem wissenschaftlichem und wirtschaftlichem Interesse. Die stetige Fortentwicklung dieser Systeme, sowohl unter Aspekten der Hard- als auch der Software, hat ein neues Technologiezeitalter eingeläutet. Verschiedene Szenarien, auf optischen, drahtgebundenen und drahtlosen Technologien basierend, wurden für diese Anwendungen entwickelt. Im 60 GHz ISM-Band (57 GHz bis 65 GHz) ist wegen der hohen Absorptionsverluste bei dieser Frequenz eine Kurzstrecken-Kommunikation mit hoher Datenrate von besonders hohem Interesse. Die Realisierung solcher Systeme erfolgt aufgrund von Kosten- und Massenproduktionsaspekten auf Basis von SiGe-HBT und CMOS Technologien. Schlüsselparameter eines 60 GHz-Transceivers sind eine hohe Ausgangsleistung, niedrige Rauschzahl, geringer Stromverbrauch und niedrige Herstellungskosten. Um den gesamten Frequenzbereich des 60 GHz ISM-Bandes abdecken zu können, wurden zahlreiche Transceivertopologien weltweit diskutiert. Die verfügbare Technologie mit ihren Schlüsselparametern ft, fmax stellt hierbei eine wichtige Randbedingung dar. In dieser Arbeit werden Aspekte des 60 GHz-Transceiver-Designs unter Verwendung einer 0,25 μm SiGe-HBT- und einer 90 nm CMOS-Technologie untersucht. Zunächst wird die Modellierung von passiven und aktiven Komponenten diskutiert. Verschiedene Techniken zur Modellextraktion basierend auf Messungen und elektromagnetischen Simulationen werden gezeigt. Für die wichtigsten passiven Bauelemente werden skalierbare Modelle entwickelt, um das Entwurfsverfahren zu präzisieren. Im nächsten Schritt werden 60 GHz CMOS- und SiGe-HBT- Leistungsverstärker untersucht. Basierend auf diesen Studien wurden zwei HBT und zwei CMOS-Endstufen konzipiert, realisiert und gemessen. Infolge der Verfügbarkeit einer hochgenauen Bauelemente-Bibliothek, ausgereifter Entwurfstechniken und der Verifikation auf Basis von EM-Simulationen konnte an den gemessenen Leistungsverstärkern eine hohe Ausgangsleistung mit guter Effizienz nachgewiesen werden. Die Ergebnisse zeigen weiterhin eine gute Übereinstimmung von Simulationen mit Messungen. Weiterhin wurden auf Basis einer 90 nm CMOS Technologie ein Heterodyne und ein OOK Transceiver entwickelt. Der Heterodyne-Transceiver mit einer Zwischenfrequenz von 20 GHz genügt dabei dem IEEE 802.15.3c Standard und erreicht eine Performance auf Höhe des internationalen Standes von Wissenschaft und Technik. Für den OOK Sender wurde eine neue Topologie entwickelt. Bei diesem Konzept bilden Modulator und Leistungsverstärker eine Einheit, woraus Vorteile hinsichtlich Ausgangsleistung, Effizienz und Chipgröße resultieren. Mit dieser Schaltung wurde in einem Systemtest eine Übertragungsrate von 6 Gbps über eine Entfernung von 4 m erfolgreich nachgewiesen.The rise of high-data-rate hungry applications has brought a new dawn to telecommunication technologies in both hardware and software development aspects. Different scenarios, mainly based on optical, coaxial and wireless systems, have been developed for these multi-gigabit communication systems. In these scenarios, the wireless system is utilized for indoor and short-range communication, which can ease the requirements on RF power and noise figure of the transceivers. However, the demand for multi-gigabit communication imposes a broadband performance requirement upon these wireless transceivers. This broadband performance requirement can be within the range of 2 GHz to 10 GHz. In order to cover such a broad frequency range, different transceiver circuit topologies have been suggested by many circuit designers. Due to the high oxygen loss in the 60 GHz range this 57 GHz to 65 GHz ISM band has attracted attention for high speed short-range communication. Moreover, the newly emerged low cost technologies (like, CMOS and SiGe HBT) have further attracted the industry to explore this communication band. The main requirements for a 60 GHz transceiver are high output power, low noise figure, low power consumption and broadband performance. To cover the whole 57 GHz to 65 GHz frequency band, numerous transceiver topologies are under discussion. The key parameter ft, fmax of the available technology define the achievable system performance. In this thesis, multiple aspects of the 60 GHz transceiver design based on the 90 nm CMOS and 0.25 μm SiGe HBT designs have been investigated. First, the modeling of passive and active components is presented. These components include capacitors, inductors, transformers, transmission lines, transistors, matching networks and RF pads. Different techniques for model extraction based on measurements and electromagnetic simulations have been examined. For inductors, transformers and capacitors scalable models have been developed. Further, the design techniques of 60 GHz CMOS and SiGe HBT power amplifiers have been studied. Based on these studies, two HBT and two CMOS power amplifiers have been designed, realized and measured. Due to accurate modeling and design techniques, high performance and good agreement with simulation has been achieved. Finally, two different types of transmitters (Heterodyne and OOK) based on the CMOS technology have been developed. The heterodyne transceiver, with an IF frequency of around 20 GHz, has been designed based on the IEEE 802.15.3c standard. This transmitter has achieved state of the art results with respect to output power, conversion gain and efficiency with a small chip size and low power consumption. For the OOK transmitter, a novel topology has been developed. In this topology, the modulator and the power amplifier have been integrated into one circuit. Due to many advantages of this new topology, this transmitter achieves higher output power and efficiency compared with state-of-the-art results. Furthermore, the realized circuit has been utilized within a wireless system where more than 6 Gbps has been successfully transmitted over a 4 m distance

Convergence of millimeter-wave and photonic interconnect systems for very-high-throughput digital communication applications

In the past, radio-frequency signals were commonly used for low-speed wireless electronic systems, and optical signals were used for multi-gigabit wired communication systems. However, as the emergence of new millimeter-wave technology introduces multi-gigabit transmission over a wireless radio-frequency channel, the borderline between radio-frequency and optical systems becomes blurred. As a result, there come ample opportunities to design and develop next-generation broadband systems to combine the advantages of these two technologies to overcome inherent limitations of various broadband end-to-end interconnect systems in signal generation, recovery, synchronization, and so on. For the transmission distances of a few centimeters to thousands of kilometers, the convergence of radio-frequency electronics and optics to build radio-over-fiber systems ushers in a new era of research for the upcoming very-high-throughput broadband services. Radio-over-fiber systems are believed to be the most promising solution to the backhaul transmission of the millimeter-wave wireless access networks, especially for the license-free, very-high-throughput 60-GHz band. Adopting radio-over-fiber systems in access or in-building networks can greatly extend the 60-GHz signal reach by using ultra-low loss optical fibers. However, such high frequency is difficult to generate in a straightforward way. In this dissertation, the novel techniques of homodyne and heterodyne optical-carrier suppressions for radio-over-fiber systems are investigated and various system architectures are designed to overcome these limitations of 60-GHz wireless access networks, bringing the popularization of multi-gigabit wireless networks to become closer to the reality. In addition to the advantages for the access networks, extremely high spectral efficiency, which is the most important parameter for long-haul networks, can be achieved by radio-over-fiber signal generation. As a result, the transmission performance of spectrally efficient radio-over-fiber signaling, including orthogonal frequency division multiplexing and orthogonal wavelength division multiplexing, is broadly and deeply investigated. On the other hand, radio-over-fiber is also used for the frequency synchronization that can resolve the performance limitation of wireless interconnect systems. A novel wireless interconnects assisted by radio-over-fiber subsystems is proposed in this dissertation. In conclusion, multiple advantageous facets of radio-over-fiber systems can be found in various levels of end-to-end interconnect systems. The rapid development of radio-over-fiber systems will quickly change the conventional appearance of modern communications.PhDCommittee Chair: Gee-Kung Chang; Committee Member: Bernard Kippelen; Committee Member: Shyh-Chiang Shen; Committee Member: Thomas K. Gaylord; Committee Member: Umakishore Ramachandra

Millimeter-wave Communication and Radar Sensing — Opportunities, Challenges, and Solutions

With the development of communication and radar sensing technology, people are able to seek for a more convenient life and better experiences. The fifth generation (5G) mobile network provides high speed communication and internet services with a data rate up to several gigabit per second (Gbps). In addition, 5G offers great opportunities of emerging applications, for example, manufacture automation with the help of precise wireless sensing. For future communication and sensing systems, increasing capacity and accuracy is desired, which can be realized at millimeter-wave spectrum from 30 GHz to 300 GHz with several tens of GHz available bandwidth. Wavelength reduces at higher frequency, this implies more compact transceivers and antennas, and high sensing accuracy and imaging resolution. Challenges arise with these application opportunities when it comes to realizing prototype or demonstrators in practice. This thesis proposes some of the solutions addressing such challenges in a laboratory environment.High data rate millimeter-wave transmission experiments have been demonstrated with the help of advanced instrumentations. These demonstrations show the potential of transceiver chipsets. On the other hand, the real-time communication demonstrations are limited to either low modulation order signals or low symbol rate transmissions. The reason for that is the lack of commercially available high-speed analog-to-digital converters (ADCs); therefore, conventional digital synchronization methods are difficult to implement in real-time systems at very high data rates. In this thesis, two synchronous baseband receivers are proposed with carrier recovery subsystems which only require low-speed ADCs [A][B].Besides synchronization, high-frequency signal generation is also a challenge in millimeter-wave communications. The frequency divider is a critical component of a millimeter-wave frequency synthesizer. Having both wide locking range and high working frequencies is a challenge. In this thesis, a tunable delay gated ring oscillator topology is proposed for dual-mode operation and bandwidth extension [C]. Millimeter-wave radar offers advantages for high accuracy sensing. Traditional millimeter-wave radar with frequency-modulated continuous-wave (FMCW), or continuous-wave (CW), all have their disadvantages. Typically, the FMCW radar cannot share the spectrum with other FMCW radars.\ua0 With limited bandwidth, the number of FMCW radars that could coexist in the same area is limited. CW radars have a limited ambiguous distance of a wavelength. In this thesis, a phase-modulated radar with micrometer accuracy is presented [D]. It is applicable in a multi-radar scenario without occupying more bandwidth, and its ambiguous distance is also much larger than the CW radar. Orthogonal frequency-division multiplexing (OFDM) radar has similar properties. However, its traditional fast calculation method, fast Fourier transform (FFT), limits its measurement accuracy. In this thesis, an accuracy enhancement technique is introduced to increase the measurement accuracy up to the micrometer level [E]

Efficient High-Performance Millimeter-Wave Front-End Integrated Circuit Designs and Techniques in SiGe BiCMOS

This dissertation presents various “efficient” design techniques for mm-wave front-end integrated circuits in regards to dc power, bandwidth, and chip size. The ideas, while suitable for different CMOS/BiCMOS processes, were implemented using a 0.18-μm SiGe BiCMOS process. The proposed techniques are validated through the actual implementations of several building blocks constituting two different front-end sections: a V-band OOK/pulse transceiver front-end and a concurrent K-/V-band receiver front-end, where K-band ranges from 18 to 27 GHz and V-band from 40 to 75 GHz. As one of the constituent components in the V-band pulse transmitter, a 60-GHz active OOK/pulse modulator has been designed with an emphasis on the enhancement in the ON/OFF isolation. Having a decent gain (higher than 10 dB), the designed modulator can also be used as a driver stage, which can save the chip area and possibly the dc power consumption compared to the combination of a switch-based passive modulator and a drive amplifier. For the receiver front-end, a wideband V-band low-noise amplifier (LNA) has been designed. Employing a wideband gain shaping technique through two T-type inter-stage matching networks, the designed LNA features very high gain-bandwidth product compared to the conventional gain-staggered wideband amplifier designs for a given dc power consumption. For the concurrent K-/V-band receiver front-end, a low-noise and variable gain stages have been designed. As the first component of the receiver chain, a concurrent dual-band LNA has been designed within a similar footprint required for a single-band amplifier operating either at K- or V-band. The most significant direct intermodulation (IM) product and harmonics are suppressed by a simple rejection network between the input and cascode devices of the 1st stage. This network also plays a crucial role in achieving dual-band input matching through Miller effect. For amplitude control purposes in the RF stage, a variable gain amplifier (VGA) operating concurrently at K- and V-bands has been developed starting from a wideband amplifier design. By replacing the inductors in the wideband design with the transformer-coupled resonators (TCRs), the critical direct IM products can be suppressed without increasing the active chip area. Gain tuning is achieved by conventional current steering, but a new technique is applied to reduce phase variation in the course of gain tuning process, which is one of the most critical concerns, especially in phased array systems

High efficiency and high frequency resonant tunneling diode sources

Terahertz (THz) technology has been generating a lot of interest due to the numerous potential applications for systems working in this previously unexplored frequency range. THz radiation has unique properties suited for high capacity communication systems and non-invasive, non-ionizing properties that when coupled with a fairly good spatial resolution are unparalleled in its sensing capabilities for use in biomedical, industrial and security fields. However, in order to achieve this potential, effective and efficient ways of generating THz radiation are required. Devices which exhibit negative differential resistance (NDR) in their current-voltage (I – V) characteristics can be used for the generation of these radio frequency (RF) signals. Among them, the resonant tunnelling diode (RTD) is considered to be one of the most promising solid-state sources for millimeter and submillimeter wave radiation, which can operate at room temperature. However, the main limitations of RTD oscillators are producing high output power and increasing the DC-to-RF conversion efficiency. Although oscillation frequencies of up to 1.98 THz have been already reported, the output power is in the range of micro-Watts and conversion efficiencies are under 1 %. This thesis describes the systematic work done on the design, fabrication, and characterization of RTD-based oscillators in monolithic microwave/millimeter-wave integrated circuits (MMIC) that can produce high output power and have a high conversion efficiency at the same time. At the device level, parasitic oscillations caused by the biasing line inductance when the diode is biased in the NDR region prevents accurate characterization and compromises the maximum RF power output. In order to stabilise the NDR devices, a common method is the use of a suitable resistor connected across the device, to make the differential resistance in the NDR region positive. However, this approach severely hinders the diode’s performance in terms of DC-to-RF conversion efficiency. In this work, a new DC bias decoupling circuit topology has been developed to enable accurate, direct measurements of the device’s NDR characteristic and when implemented in an oscillator design provides over a 10-fold improvement in DC-to-RF conversion efficiency. The proposed method can be adapted for higher frequency and higher power devices and could have a major impact with regards to the adoption of RTD technology, especially for portable devices where power consumption must be taken into consideration. RF and DC characterization of the device were used in the realization on an accurate large-signal model of the RTD. S-parameter measurements were used to determine an accurate small-signal model for the device’s capacitance and inductance, while the extracted DC characteristics where used to replicate the I-V characteristics. The model is able to replicate the non-stable behavior of RTD devices when biased in the NDR region and the RF characteristics seen in oscillator circuits. It is expected that the developed model will serve in future optimization processes of RTD devices in millimeter and submillimeter wave applications. Finally, a wireless data transmission link operating in the Ka-band (26.5 GHz – – 40 GHz) using two RTDs operating as a transmitter and receiver is presented in this thesis. Wireless error-free data transfer of up to 2 gigabits per second (Gbit/s) was achieved at a transmission distance of 15 cm. In summary, this work makes important contributions to the accurate characterization, and modeling of RTDs and demonstrates the feasibility of this technology for use in future portable wireless communication systems and imaging setups

Multi-Gigabaud Solutions for Millimeter-wave Communication

With the growing number of mobile network and internet services subscriptions, faster communication will provide a better experience for users. In the next generation mobile network, the fifth generation (5G), communication data rate will achieve several Gigabits per second with ultra-low latency. The capacity enhancement of the mobile backhaul and fronthaul is a challenge. The transmission capacity can be enhanced by increasing the bandwidth, increasing the spectrum efficiency and increasing both the bandwidth and the spectrum efficiency at the same time. \ua0Millimeter-wave frequency bands have the bandwidth in the order of GHz which provide great opportunities to realize high data rate communications. In this case, millimeter-wave frontend modules and wideband modems are needed in communication systems. In this thesis, a 40 Gbps real-time differential quadrature phase shift keying (DQPSK) modem has been presented to support high-speed communications [A]. As a complete system, it aims to work together with the D-band frontend module published in [1] providing more than 40 GHz bandwidth. In this modem, the modulator is realized in a single field programmable gate array (FPGA) and the demodulator is based on analog components. Although millimeter-wave frequency bands could provide wide available bandwidth, it is challenging to generate high output power of the carrier signal. In addition, the transmitter needs to back off several dB in output power in order to avoid the non-linear distortion caused by power amplifiers. In this thesis, an outphasing power combining transmitter is proposed [B] to use the maximum output power of power amplifiers while maintaining the signal quality at the same time. This transmitter is demonstrated at E-band with commercially available components.Increasing the spectrum efficiency is an additional method to enhance the transmission capacity. High order modulation signals such as quadrature amplitude modulation (QAM) signals are commonly used for this purpose.\ua0 In this case, receivers usually require coherent detection in order to demodulate the signals. Limited by the sampling rate of the analog to digital converters (ADCs), the traditional digital carrier recovery methods can be only applied to a symbol rate lower than the sampling rate. A synchronous baseband receiver is proposed [C] with a carrier recovery subsystem which only requires a low-speed ADC with a sampling rate of 100 MSps