Integrated Circuits and Systems for Millimeter-Wave Frequencies

In the first section of this thesis, mm-wave circuit- and system-level solutions for addition of multi-user service to conventional multi-antenna phased array architectures will be introduced. The proposed architecture will enhance the link capacity, co-channel user service and hardware cost compared to conventional solutions. Theory and design of the circuits and system are detailed and comprehensive measurement results are presented verifying the system-level functionality. First section is named A Millimeter-Wave Partially-Overlapped Beamforming-MIMO Receiver: Theory, Design, and Implementation. More specifically, this section presents an analysis and design of a partially-overlapped beamforming-MIMO architecture capable of achieving higher beamforming and spatial multiplexing gains with lower number of elements compared to conventional architectures. As a proof of concept, a 4-element beamforming-MIMO receiver (RX) covering 64-67 GHz frequency band enabling 2-stream concurrent reception is designed and measured. By partitioning the RX elements into two clusters and partially overlapping these clusters to create two 3-element beamformers, both phased-array (coherent beamforming) as well as MIMO (spatial multiplexing) features are simultaneously acquired. 6-bit phase shifters with 360° phase control and 5-bit VGAs with 11 dB range are designed to enable steering of the two RX clusters toward two arbitrary angular locations corresponding to two users. Fabricated in a 130-nm SiGe BiCMOS process, the RX achieves a 30.15 dB maximum direct conversion gain and a 9.8 dB minimum noise figure (NF) across 548 MHz IF bandwidth. S-parameter-based array factor measurements verify spatial filtering of the interference and spatial multiplexing in this RX chip.In the second section of this thesis, energy-efficient ultra-high speed transceiver architectures will be presented. Current high-speed transceivers rely on high-sampling-rate high-resolution power-hungry analog-to-digital converters or digital-to-analog converters at the interface of analog and digital circuitries. However, design of these backend data-converters are extremely power-hungry at very high speeds in a fully-integrated end-to-end scenario (i.e. RF-to-Bits, Bits-to-RF). Novel system-level architectures will be presented that obviate the need for such costly data converters and will significantly relax the complexity of digital signal-processing. The proposed architecture will result in orders of magnitude energy saving at ultra-high speeds. Theory, design, and measurement results of the highest-speed, highly energy-efficient fully-integrated end-to-end transceiver will be discussed in this section. Second section is named A Millimeter-Wave Energy-Efficient Direct-Demodulation Receiver: Theory, Design, and Implementation. More precisely, this section presents the theory, design, and implementation of an 8PSK direct-demodulation receiver based on a novel multi-phase RF-correlation concept. The output of this RF-to-bits receiver architecture is demodulated bits, obviating the need for power-hungry high-speed-resolution data converters. A single-channel 115-135-GHz receiver prototype was fabricated in a 55-nm SiGe BiCMOS process. A max conversion gain of 32 dB and a min noise figure (NF) of 10.3 dB was measured. A data-rate of 36 Gbps was wirelessly measured at 30 cm distance with the received 8PSK signal being directly demodulated on-chip at a bit-error-rate (BER) of 1e-6. The measured receiver sensitivity at this BER is -41.28 dBm. The prototype occupies 2.5 by 3.5 mm squared of die area including PADs and test circuits (2.5 mm squared active area) and consumes a total DC power of 200.25 mW

Low-Power Integrated Circuits For Biomedical Applications

With thousands new cases of spinal cord injury reported everyday, many people suffer from paralysis and loss of sensation in both legs. Beside the healthcare costs, such a state severely deteriorates the patients' quality of life and may even lead to additional medical conditions. Therefore, there is a growing need for cyber-physical systems to restore the walking ability through bypassing the damaged spinal cord. This goal can be achieved by monitoring and processing patient's brain signals to enable brain-directed control of prosthetic legs. Among several existing methods to record brain signals, electrocorticography (ECoG) has gained popularity due to being robust to motion artifacts, having high spatial resolution and signal to noise ratio, being moderately invasive and the possibility of chronic implantation of recording grids with no or minor scar tissue formation. The latest property is of particular importance for the whole system to be a viable fully implantable solution. Furthermore, the implanted system has to operate independently with no or minimal need of external hardware (e.g. a bulky personal computer) to be individually and socially accepted. To implement a fully implantable system, low-power and miniaturized electronics are needed to reduced heat generation, increase battery life-time and be minimally intrusive. These requirements indicate that many of the system's components should be custom-designed to integrated as much functionality as possible in a given real estate. This thesis presents silicon tested prototypes of several building blocks for the envisioned system, namely, ultra low-power brain signal acquisition front-ends, a low-power and inductorless MedRadio transceiver, and a fast start-up crystal oscillator. Brain signal acquisition front-ends provide low noise amplification of weak ECoG biosignals. MedRadio transceiver enables communication between the implant and end effectors or base station (e.g. prosthetic legs or desktop computer). Crystal oscillator generates the reference signal for other system's components such as analog to digital converter. Novel techniques to improve important performance parameters (power consumption, low noise operation and interference resilience) have been introduced. Electrical, in-vitro and in-vivo experimental measurements have verified the functionality and performance of each design

High Gain Antenna Array Design for 5G & MIMO Antenna Systems using Microstrip Ridge Gap Waveguide

The demand for high data rates and the unavailability of low-frequency bands have driven the need to explore and develop millimeter-wave (mm-wave) frequency bands. Indeed, the development of mm-wave frequencies has led to smaller radio frequency (RF) components and more compact profiles, creating more design constraints and challenges. Millimeter-wave technologies are the best-suited candidates that meet the requirements of 5G standards; specifically, for indoor communication, which requires higher gain and more directive beams. Gap waveguide technologies can be used to design high-gain antenna arrays and multiple input multiple output antenna systems (MIMO). In this thesis, we are mainly focusing on Microstrip Ridge Gap Waveguide (MRGW) to design the antenna array systems for the 60 GHz band. Therefore, it is necessary to facilitate the design procedures and propose new design techniques. Here, we propose new design techniques for a large antenna array system using MRGW. The work of this thesis can be divided into two parts. Firstly, developing an efficient modeling and design tool for the MRGW to facilitate the design process. Recently, the use of MRGW has increased due to the need for self-packaged and low loss structures for millimeter-wave applications. The MRGW consists of a grounded textured surface, which is representing an artificial magnetic conductor (AMC) surface. The AMC surface is loaded with a thin low dielectric constant substrate with a printed strip topped with another air-filled or dielectric-filled substrate in which the wave propagates between the strip and the conducting plate covering such a substrate. Currently, full-wave and optimization tools are usually used to design the MRGW structure, which makes the design slow and computationally expensive. Thus, an efficient modeling and design tool for the MRGW is proposed. Empirical expressions are developed for different MRGW parameters to provide the effective dielectric constant, characteristic impedance, and the dispersion effect. The expressions are verified with the full-wave solution. The results show the potential of the proposed approach in modeling and designing the MRGW structure. Secondly, an efficient procedure to design a large finite planar array and its corporate feeding network is presented. The procedure is verified by an 8 × 8 and 16 ×16 array of magneto-electric (ME) dipoles fed by a network of MRGW. The procedure is based on designing the corporate feeding network by replacing the elements ports with the corresponding effective input impedance of each element that accounts for the mutual coupling between the antenna elements. In addition, the far-field characteristics of the array parameters such as the directivity, gain, and radiation patterns are predicted using pattern multiplication, including the mutual coupling effects. The results are verified with the full-wave numerical solution. The procedure requires limited resources and speed up the design cycle. The use of the MRGW helps in having the feeding network lines to be titer than using the ridge gap technology. Thus, allowing the distance between the radiating elements becomes smaller than one wavelength to avoid grating lobes. In addition, to avoid undesired bends and very tight lines that cause undesired interaction between the lines, unique power dividers are designed. Furthermore, a transition from waveguide WR-15 to the MRGW is proposed to feed two halves of the array antenna perfect out of phase at all frequencies and rotating each half to form a mirrored array that better radiation pattern symmetry and low cross-polarization. Then, this procedure is implemented to design a circularly polarized antenna array with excellent performance. To further enhance the antenna, gain, and reduce the number of elements, a superstrate dielectric lens with the proper parameters is added. Study of a 4 × 4 MIMO system is studied, where each antenna is a sub-array to achieve the high gain requirements. Finally, A low-profile, compact, and high-efficiency monopulse array antenna has been presented. The monopulse is built based on a hybrid coupler that has a wideband response for the reflection and the transmission coefficients. Then the monopulse system is used to present a multiplexing antenna system for short-range in the near filed region wireless communication. The multiplexing system works as a MIMO system that has four independent channels. The performance of the system is evaluated through the simulation, which shows that it can be a promising candidate for the next wireless communication systems

Compact and Efficient Millimetre-Wave Circuits for Wideband Applications

Radio systems, along with the ever increasing processing power provided by computer technology, have altered many aspects of our society over the last century. Various gadgets and integrated electronics are found everywhere nowadays; many of these were science-fiction only a few decades ago. Most apparent is perhaps your ``smart phone'', possibly kept within arm's reach wherever you go, that provides various services, news updates, and social networking via wireless communications systems. The frameworks of the fifth generation wireless system is currently being developed worldwide. Inclusion of millimetre-wave technology promise high-speed piconets, wireless back-haul on pencil-beam links, and further functionality such as high-resolution radar imaging. This thesis addresses the challenge to provide signals at carrier frequencies in the millimetre-wave spectrum, and compact integrated transmitter front-ends of sub-wavelength dimensions. A radio frequency pulse generator, i.e. a ``wavelet genarator'', circuit is implemented using diodes and transistors in III--V compound semiconductor technology. This simple but energy-efficient front-end circuit can be controlled on the time-scale of picoseconds. Transmission of wireless data is thereby achieved at high symbol-rates and low power consumption per bit. A compact antenna is integrated with the transmitter circuit, without any intermediate transmission line. The result is a physically small, single-chip, transmitter front-end that can output high equivalent isotropically radiated power. This element radiation characteristic is wide-beam and suitable for array implementations

Phase-Locked-Based Phased Array for mm-Wave/Terahertz Radiators

Fully integrated implementation of silicon mm-wave/THz radiators and phased arrays is of great interest for various applications such as high data-rate communication, spectroscopy, and imaging. These applications require wide frequency tuning, sufficient radiated power, and variable phase shifting between adjacent sources to perform beam steering. As a result, recent studies have focused on new potentials and existing challenges. The critical issue associated with any system operating at mm-wave/terahertz frequency is a flexible, integrated source providing a sufficient level of power. mm-wave/THz phased array systems demonstrate a potential to overcome the limited available power of transistors close to the maximum oscillation frequency caused by the coherent combining in a phased array. In addition, at mm-wave frequency range, the higher number of these available coherent sources are implemented to compensate for the reduced power of a single source. Initially the design of a 53-61GHz low-power charge-pump PLL is presented. This integer-N type-II PLL employs a class-D V-band VCO. Transistors in the VCO enter deep triode region to yield low DC power and low phase-noise performance. Pros and cons of the triode region have been studied in this chapter. We have explained how this region has been accurately exploited to improve the phase-noise performance. This is unlike the general notion that the triode region degrades phase-noise performance in oscillators. The PLL is fabricated in a standard 65nm CMOS process. The VCO consumes the minimum power of 10.6mW from 0.8V supply. The PLL achieves a wide tuning range of 13% from 53.35 to 60.83GHz and a phase noise of -88 dBc/Hz at 1MHz offset, while consuming a minimum DC power of 48mW. This PLL can be used as part of the LO generation network for millimeter-wave phased-array transceivers. The main challenge of phased-array systems at mm-wave/THz frequency is the design of phase shifters at these frequencies. Passive phase shifters result in undesired power loss. Alternatively, active phase shifters cannot either provide a wide bandwidth with a constant gain or operate in that frequency range. The goal of this study is to achieve a high frequency phased array with stable, controllable, and high accuracy frequency. This is accomplished by combining a PLL with phased array signal generation. This chapter presents a 1x2 PLL-based phased-array radiator operating at 450.4-to- 486.68GHz and 1x2 PLL-based phased-array system operating at 112.66 -to- 121.67GHz. In this work, by utilizing two PLLs, the required phase shift is generated without a need for the separate phase shifting building blocks. Furthermore, this novel topology avoids routing at high frequency which attenuates the signal power and at the same time uses low frequency connections that can be readily scaled to simplify the design. This work is fabricated in a standard 65nm CMOS process and completely scalable to fully exploits advantages of phased-array system. Finally, a 64-67GHz variable gain attenuator (VGA) is proposed for the amplitude control at each RF channel of a 64-67GHz partially-overlapped phase-amplitude-controlled 4-element beamforming-MIMO receiver. This VGA presents a measured 11dB dynamic range, while exhibiting RMS gain error smaller than 0.32dB within the RF bandwidth. This was achieved by incorporating circuit and EM techniques enabling wide dynamic rang with small gain variation at this frequency range