Millimeter-Wave and Terahertz Transceivers in SiGe BiCMOS Technologies

This invited paper reviews the progress of silicon–germanium (SiGe) bipolar-complementary metal–oxide–semiconductor (BiCMOS) technology-based integrated circuits (ICs) during the last two decades. Focus is set on various transceiver (TRX) realizations in the millimeter-wave range from 60 GHz and at terahertz (THz) frequencies above 300 GHz. This article discusses the development of SiGe technologies and ICs with the latter focusing on the commercially most important applications of radar and beyond 5G wireless communications. A variety of examples ranging from 77-GHz automotive radar to THz sensing as well as the beginnings of 60-GHz wireless communication up to THz chipsets for 100-Gb/s data transmission are recapitulated. This article closes with an outlook on emerging fields of research for future advancement of SiGe TRX performance

Millimetre-wave radar development for high resolution detection

Automotive technology today is focusing on autonomous vehicle development. The sensors for these systems include radars due to their robustness against adverse weather conditions such as rain, fog, ash or snow. In this constant search for advancement, high resolution systems play a central role in target detection and avoidance. In this PhD project, these methods have been researched and engineered to leverage the best radar resolution for collision avoidance systems. The first part of this thesis will focus on the existing systems consisting of the state-of-the-art at the time of writing and explain what makes a high resolution radar and how it can cover the whole field of view. The second part will focus on how a non-uniform sparse radar system was simulated, developed and benchmarked for improved radar performance up to 40% better than conventional designs. The third part will focus on signal processing techniques and how these methods have achieved high resolution and detection: large virtual aperture array using Multiple Input Multiple Output (MIMO) systems, beampattern multiplication to improve side-lobe levels and compressive sensing. Also, the substrate-integrated waveguide (SIW) antennas which have been fabricated provide a bandwidth of 1.5GHz for the transmitter and 2GHz at the receiver. This has resulted in a range resolution of 10 cm. The four part of this thesis presents the measurements which have been carried out at the facilities within Heriot-Watt University and also at Netherlands Organisation for Applied Scientific Research (TNO). The results were better than expected since a two transmitter four receiver system was able to detect targets which have been separated at 2.2◦ in angle in the horizontal plane. Also, compressive sensing was used as a high resolution method for obtaining fine target detection and in combination with the multiplication method showed improved detection performance with a 20 dB side-lobe level suppression. The measurement results from the 6-months placements are presented and compared with the state-of the art, revealing that the developed radar is comparable in performance to high-grade automotive radars developed in the industry

Ball Grid Array Module with Integrated Shaped Lens for 5G Backhaul/Fronthaul Communications in F-Band

In this paper, we propose a ball grid array (BGA) module with an integrated 3-D-printed plastic lens antenna for application in a dedicated 130 GHz OOK transceiver that targets the area of 5G backhaul/fronthaul systems. The main design goal was the full integration of a small footprint antenna with an energy-efficient transceiver. The antenna system must be compact and cost effective while delivering an approximately 30 dBi gain in the working band, defined as 120 to 140 GHz. Accordingly, a 2×2 array of aperture-coupled patch antennas was designed in the 7×7×0.362 mm3 BGA module as the feed antenna of the lens. This achieved a 7.8 dBi realized gain, broadside polarization purity above 20 dB, and over 55% total efficiency from 110 to 140 GHz (20% bandwidth). A plastic elliptical lens 40 mm in diameter and 42.3 mm in height was placed on top of the BGA module. The antenna achieved a return loss better than ?10 dB and a 28 dBi realized gain from 114 to 140 GHz. Finally, active measurements demonstrated a >12 Gbps Tx/Rx link at 5 m with bit error rate (BER) < 10?6 at 1.6 pJ/b/m. These results pave the way for future cost-effective, energy-efficient, high-data rate backhaul/fronthaul systems for 5G communications.info:eu-repo/semantics/acceptedVersio

ON FUNDAMENTAL OPERATING PRINCIPLES AND RANGE-DOPPLER ESTIMATION IN MONOLITHIC FREQUENCY-MODULATED CONTINUOUS-WAVE RADAR SENSORS

The diverse application areas of emerging monolithic noncontactradar sensors that are able to measure object’s distance and velocity is expected to grow in the near future to scales that are now nearly inconceivable. A classical concept of frequency-modulated continuous-wave (FMCW) radar, tailored to operate in the millimeter-wave (mm-wave) band, is well-suited to be implemented in the baseline CMOS or BiCMOS process technologies. High volume production could radically cut the cost and decrease the form factorof such sensing devices thus enabling their omnipresence in virtually every field. This introductory paper explains the key concepts of mm-wave sensing starting from a chirp as an essential signal in linear FMCW radars. It further sketches the fundamental operating principles and block structure of contemporary fully integrated homodyne FMCW radars. Crucial radar parameters like the maximum unambiguously measurable distance and speed, as well as rangeand velocity resolutions are specified and derived. The importance of both beat tones in the intermediate frequency (IF) signal and the phase in resolving small spatial perturbations and obtaining the 2-D range-Doppler plot is pointed out. Radar system-level trade-offs and chirp/frame design strategies are explained. Finally, the nonideal and second-order effects are commented and the examples of practical FMCW transmitter and receiver implementations are summarized

A 37-40 GHz Dual-Polarized 16-Element Phased-Array Antenna with Near-Field Probes

With the development of fifth-generation (5G) communication networks, in order to meet the growing demand for high-speed and low-latency wireless communication services, channel capacity has become the main driving force for choosing millimeter wave (mm-wave) over over-crowded sub-6 GHz frequency bands. Recently, beamforming phased array attracts significant research efforts as it is a promising solution and unique in its ability to overcome the high path-loss at high frequency, provide fast beam steering and deliver better user-ends experience. However, to alleviate the issues that associated with beamforming phased array, such as imbalance between array elements and non-linearity caused by power-amplifiers (PAs) in beamforming channels, far-field (FF) based array calibration and digital pre-distortion (DPD) need to be performed, which is not practical in real world scenario. This thesis presents a low-cost 16-element dual-polarized mm-wave antenna-on-printed circuit board (PCB) transmitter RF beamforming array with embedded near-field probes (NFPs) at 37-40 GHz. The elements are orthogonal, proximity-coupled feed dual-polarized patch antenna with a spacing of 0.5λ within 2x2 subarray and 0.6λ between 2x2 subarray at 38.5 GHz, resulting in maximum 17.7 dB gain with a scan angle of +/-50◦, +/-20◦ in azimuth and +/-20◦, +/-50◦ in elevation for vertical polarization and horizontal polarization, respectively. Without affecting phased array performance, the NFPs achieve flat and comparable coupling magnitude and group delay to the closet RF chain for both polarizations, across operating frequency range. This ensures the quality of received output signal from phased array to implement array calibration and DPD. The configuration of embedded NFPs maintains the scalability of phased array and eliminate the needs of impractical FF reference probe for array calibration and DPD

A High Performance Micromachined Sub-Millimeter-Wave Radar Technology

Motivated by the recent interest in high millimeter-wave (MMW) and sub-MMW radar sensors for applications ranging from navigation and mapping in autonomous systems to public safety and standoff detection of concealed weapons, this work presents the technology in support of a novel sub-MMW radar with minimal Size, Weight, and Power consumption (SWaP). This includes development of novel design, microfabrication, and measurement methods and techniques to develop the passive RF front-end of the radar system operating at 240 GHz. The sub-MMW radar system is designed for navigation and mapping applications in autonomous systems. The salient features of the proposed radar are its ultra-lightweight (less than 5 grams), compact form factor (2 cm3), low power consumption (6.7 mW for 1 fps), and ease of scalability to higher frequencies (up to 1 THz). This work introduces novel components and sub-systems for the RF front-end of the radar system. This includes developing high performance radar antenna systems as well as the chip packaging and integration technology with the associated transitions for realization of the radar system. In order to satisfy the requirements for high resolution and wide field of view for this imaging and navigation radar sensor, frequency scanning beam-steering antennas are developed to achieve ±25˚ of beam steering with a very narrow beam of 2.5˚ in the direction of scan. The designed array antenna has over 600 radiating elements and exhibits a radiation efficiency of over 55% and a gain of over 30 dBi over the entire operation frequency range. Additionally, for polarimetry applications, two versions of the antenna with both co- and cross-polarizations are developed to allow full-polarimetry imaging at sub-MMW frequencies. Another contribution of this work is development of a novel chip packaging methodology with the associated biasing network for sub-MMW integration of active and passive MMICs in the RF front-end. The packaging method offers a compact, low-loss, and wideband integration solution in the sub-MMW to terahertz (THz) frequency band which can be standardized for reliable and repeatable integrations at such frequencies. Due to the small wavelength at MMW to THz frequency band, fabrication of sub-MMW components requires high fabrication tolerances and accuracies, which is costly and hard to achieve with the standard machining techniques. To overcome this problem, in this work novel silicon micromachining methods are developed to enable reliable fabrication of complex structures, such as the radar RF front end, with low mass and low cost. The fabrication method allows seamless realization of the entire radar RF front-end on a single silicon block with a compact form factor and high level of integration. Repeatable and reliable characterization of sub-MMW components and sub-systems is a very challenging task and one major contribution of this dissertation pertains to development of novel measurement techniques to enable reliable on-wafer characterization of such devices in the MMW to THz band. This includes development of a novel waveguide probe measurement technique along with specially designed probes and the associated transitions for on-wafer S-parameter measurements at sub-MMW frequencies. Additionally, a novel on-wafer near-field measurement method is developed to allow pattern and power characterization of the antennas at sub-MMW frequencies. These methods are employed to perform full on-wafer characterization of the micromachined RF front-end components, including the antennas as well as the chip packaging, where excellent agreement of designed and measured results are shown.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/140879/1/arminjam_1.pd

Radar networks: A review of features and challenges

Networks of multiple radars are typically used for improving the coverage and tracking accuracy. Recently, such networks have facilitated deployment of commercial radars for civilian applications such as healthcare, gesture recognition, home security, and autonomous automobiles. They exploit advanced signal processing techniques together with efficient data fusion methods in order to yield high performance of event detection and tracking. This paper reviews outstanding features of radar networks, their challenges, and their state-of-the-art solutions from the perspective of signal processing. Each discussed subject can be evolved as a hot research topic.Comment: To appear soon in Information Fusio

High Performance Local Oscillator Design for Next Generation Wireless Communication

Local Oscillator (LO) is an essential building block in modern wireless radios. In modern wireless radios, LO often serves as a reference of the carrier signal to modulate or demod- ulate the outgoing or incoming data. The LO signal should be a clean and stable source, such that the frequency or timing information of the carrier reference can be well-defined. However, as radio architecture evolves, the importance of LO path design has become much more important than before. Of late, many radio architecture innovations have exploited sophisticated LO generation schemes to meet the ever-increasing demands of wireless radio performances. The focus of this thesis is to address challenges in the LO path design for next-generation high performance wireless radios. These challenges include (1) Congested spectrum at low radio frequency (RF) below 5GHz (2) Continuing miniaturization of integrated wireless radio, and (3) Fiber-fast (>10Gb/s) mm-wave wireless communication. The thesis begins with a brief introduction of the aforementioned challenges followed by a discussion of the opportunities projected to overcome these challenges. To address the challenge of congested spectrum at frequency below 5GHz, novel ra- dio architectures such as cognitive radio, software-defined radio, and full-duplex radio have drawn significant research interest. Cognitive radio is a radio architecture that opportunisti- cally utilize the unused spectrum in an environment to maximize spectrum usage efficiency. Energy-efficient spectrum sensing is the key to implementing cognitive radio. To enable energy-efficient spectrum sensing, a fast-hopping frequency synthesizer is an essential build- ing block to swiftly sweep the carrier frequency of the radio across the available spectrum. Chapter 2 of this thesis further highlights the challenges and trade-offs of the current LO gen- eration scheme for possible use in sweeping LO-based spectrum analysis. It follows by intro- duction of the proposed fast-hopping LO architecture, its implementation and measurement results of the validated prototype. Chapter 3 proposes an embedded phase-shifting LO-path design for wideband RF self-interference cancellation for full-duplex radio. It demonstrates a synergistic design between the LO path and signal to perform self-interference cancellation. To address the challenge of continuing miniaturization of integrated wireless radio, ring oscillator-based frequency synthesizer is an attractive candidate due to its compactness. Chapter 4 discussed the difficulty associated with implementing a Phase-Locked Loop (PLL) with ultra-small form-factor. It further proposes the concept sub-sampling PLL with time- based loop filter to address these challenges. A 65nm CMOS prototype and its measurement result are presented for validation of the concept. In shifting from RF to mm-wave frequencies, the performance of wireless communication links is boosted by significant bandwidth and data-rate expansion. However, the demand for data-rate improvement is out-pacing the innovation of radio architectures. A >10Gb/s mm-wave wireless communication at 60GHz is required by emerging applications such as virtual-reality (VR) headsets, inter-rack data transmission at data center, and Ultra-High- Definition (UHD) TV home entertainment systems. Channel-bonding is considered to be a promising technique for achieving >10Gb/s wireless communication at 60GHz. Chapter 5 discusses the fundamental radio implementation challenges associated with channel-bonding for 60GHz wireless communication and the pros and cons of prior arts that attempted to address these challenges. It is followed by a discussion of the proposed 60GHz channel- bonding receiver, which utilizes only a single PLL and enables both contiguous and non- contiguous channel-bonding schemes. Finally, Chapter 6 presents the conclusion of this thesis

Four-element phased-array beamformers and a self-interference canceling full-duplex transciver in 130-nm SiGe for 5G applications at 26 GHz

This thesis is on the design of radio-frequency (RF) integrated front-end circuits for next generation 5G communication systems. The demand for higher data rates and lower latency in 5G networks can only be met using several new technologies including, but not limited to, mm-waves, massive-MIMO, and full-duplex. Use of mm-waves provides more bandwidth that is necessary for high data rates at the cost of increased attenuation in air. Massive-MIMO arrays are required to compensate for this increased path loss by providing beam steering and array gain. Furthermore, full duplex operation is desirable for improved spectrum efficiency and reduced latency. The difficulty of full duplex operation is the self-interference (SI) between transmit (TX) and receive (RX) paths. Conventional methods to suppress this interference utilize either bulky circulators, isolators, couplers or two separate antennas. These methods are not suitable for fully-integrated full-duplex massive-MIMO arrays. This thesis presents circuit and system level solutions to the issues summarized above, in the form of SiGe integrated circuits for 5G applications at 26 GHz. First, a full-duplex RF front-end architecture is proposed that is scalable to massive-MIMO arrays. It is based on blind, RF self-interference cancellation that is applicable to single/shared antenna front-ends. A high resolution RF vector modulator is developed, which is the key building block that empowers the full-duplex frontend architecture by achieving better than state-of-the-art 10-b monotonic phase control. This vector modulator is combined with linear-in-dB variable gain amplifiers and attenuators to realize a precision self-interference cancellation circuitry. Further, adaptive control of this SI canceler is made possible by including an on-chip low-power IQ downconverter. It correlates copies of transmitted and received signals and provides baseband/dc outputs that can be used to adaptively control the SI canceler. The solution comes at the cost of minimal additional circuitry, yet significantly eases linearity requirements of critical receiver blocks at RF/IF such as mixers and ADCs. Second, to complement the proposed full-duplex front-end architecture and to provide a more complete solution, high-performance beamformer ICs with 5-/6- b phase and 3-/4-b amplitude control capabilities are designed. Single-channel, separate transmitter and receiver beamformers are implemented targeting massive- MIMO mode of operation, and their four-channel versions are developed for phasedarray communication systems. Better than state-of-the-art noise performance is obtained in the RX beamformer channel, with a full-channel noise figure of 3.3 d