Precision at Scale: System Design from Tiny Biosensors to Giant Arrays

In order to change the world, technological advancements must be made affordable and available for the general public to use. In other words, we must be able to scale our inventions effectively. Silicon integrated circuits are crucial components in scaling electronic systems because they are mass producible and offer a phenomenal cost-to-complexity ratio. This thesis summarizes the author’s work on highly scalable sensor and array systems. It presents three high precision systems, that demonstrate how the use of highly functional radio-frequency integrated circuits enables the realization of previously unfeasible architectures

A Sub-Picosecond Hybrid DLL for Large-Scale Phased Array Synchronization

A large-scale timing synchronization scheme for scalable phased arrays is presented. This approach utilizes a DLL co-designed with a subsequent 2.5GHz PLL. The DLL employs a low noise, fine/coarse delay tuning to reduce the in-band rms jitter to 323fs, an order of magnitude improvement over previous works at similar frequencies. The DLL was fabricated in a 65nm bulk CMOS process and was characterized from 27MHz to 270MHz. It consumes up to 3.3mW from a 1V power supply and has a small footprint of 0.036mm^2

A Sub-Picosecond Hybrid DLL for Large-Scale Phased Array Synchronization

A large-scale timing synchronization scheme for scalable phased arrays is presented. This approach utilizes a DLL co-designed with a subsequent 2.5GHz PLL. The DLL employs a low noise, fine/coarse delay tuning to reduce the in-band rms jitter to 323fs, an order of magnitude improvement over previous works at similar frequencies. The DLL was fabricated in a 65nm bulk CMOS process and was characterized from 27MHz to 270MHz. It consumes up to 3.3mW from a 1V power supply and has a small footprint of 0.036mm^2

Dynamic Focusing of Large Arrays for Wireless Power Transfer and Beyond

We present architectures, circuits, and algorithms for dynamic 3-D lensing and focusing of electromagnetic power in radiative near- and far-field regions by arrays that can be arbitrary and nonuniform. They can benefit applications such as wireless power transfer at a distance (WPT-AD), volumetric sensing and imaging, high-throughput communications, and optical phased arrays. Theoretical limits on system performance are calculated. An adaptive algorithm focuses the power at the receiver(s) without prior knowledge of its location(s). It uses orthogonal bases to change the phases of multiple elements simultaneously to enhance the dynamic range. One class of such 2-D orthogonal and pseudo-orthogonal masks is constructed using the Hadamard and pseudo-Hadamard matrices. Generation and recovery units (GU and RU) work collaboratively to focus energy quickly and reliably with no need for factory calibration. Orthogonality enables batch processing in high-latency and low-rate communication settings. Secondary vector-based calculations allow instantaneous refocusing at different locations using element-wise calculations. An emulator enables further evaluation of the system. We demonstrate modular WPT-AD GUs of up to 400 elements utilizing arrays of 65-nm CMOS ICs to focus power on RUs that convert the RF power to dc. Each RFIC synthesizes 16 independently phase-controlled RF outputs around 10 GHz from a common single low-frequency reference. Detailed measurements demonstrate the feasibility and effectiveness of RF lensing techniques presented in this article. More than 2 W of dc power can be recovered through a wireless transfer at distances greater than 1 m. The system can dynamically project power at various angles and at distances greater than 10 m. These developments are another step toward unified wireless power, sensing, and communication solutions in the future

A lightweight tile structure integrating photovoltaic conversion and RF power transfer for space solar power applications

We demonstrate the development of a prototype lightweight (1.5 kg/m^3) tile structure capable of photovoltaic solar power capture, conversion to radio frequency power, and transmission through antennas. This modular tile can be repeated over an arbitrary area to forma large aperture which could be placed in orbit to collect sunlight and transmit electricity to any location. Prototype design is described and validated through finite element analysis, and high-precision ultra-light component manufacture and robust assembly are described

A lightweight tile structure integrating photovoltaic conversion and RF power transfer for space solar power applications

We demonstrate the development of a prototype lightweight (1.5 kg/m^3) tile structure capable of photovoltaic solar power capture, conversion to radio frequency power, and transmission through antennas. This modular tile can be repeated over an arbitrary area to forma large aperture which could be placed in orbit to collect sunlight and transmit electricity to any location. Prototype design is described and validated through finite element analysis, and high-precision ultra-light component manufacture and robust assembly are described

A flexible phased array system with low areal mass density

Phased arrays are multiple antenna systems capable of forming and steering beams electronically using constructive and destructive interference between sources. They are employed extensively in radar and communication systems but are typically rigid, bulky and heavy, which limits their use in compact or portable devices and systems. Here, we report a scalable phased array system that is both lightweight and flexible. The array architecture consists of a self-monitoring complementary metal–oxide–semiconductor-based integrated circuit, which is responsible for generating multiple independent phase- and amplitude-controlled signal channels, combined with flexible and collapsible radiating structures. The modular platform, which can be collapsed, rolled and folded, is capable of operating standalone or as a subarray in a larger-scale flexible phased array system. To illustrate the capabilities of the approach, we created a 4 × 4 flexible phased array tile operating at 9.4–10.4 GHz, with a low areal mass density of 0.1 g cm^(−2). We also created a flexible phased array prototype that is powered by photovoltaic cells and intended for use in a wireless space-based solar power transfer array

A Coupled Inductive Bridge for Magnetic Sensing Applications

A highly-sensitive magnetic sensor with excellent long-term stability is presented. We modify a conventional all-inductor AC Wheatstone Bridge by coupling two inductor pairs in a cross-coupled configuration which halves its size and doubles its sensitivity, while maintaining a fully differential output that reduces common-mode induced offset and drift. The sensor was fabricated with integrated excitation and receiver circuitry in a 65nm bulk CMOS process. It operates between 770MHz and 1.45GHz, has an effective sensing area of 200µm × 200µm, and reliably and continuously detects single 4.5µm magnetic label beads without significant drift over time periods notably longer than previously reported works. To our best knowledge, this is the first demonstration of a magnetic sensor using a fully symmetric, gain enhanced, and all-inductor coupled bridge circuit

Analysis and Design of Coupled Inductive Bridges for Magnetic Sensing Applications

This paper presents the analysis and design of a novel magnetic sensor. We study the underlying physics of inductance shift sensors as a special case of the broader family of magnetic energy deviation sensors. The result is a quantitative definition of performance metrics with all assumptions and approximations explicitly stated. This analysis is then used to design a modified ac Wheatstone bridge that uses two inductor-pairs in a cross-coupled configuration, to half its size and double its transducer gain while maintaining a fully differential structure with a matched frequency response. A proof-of-concept sensor was fabricated with peripheral circuitry in a 65-nm bulk CMOS process to operate between 770 and 1450 MHz with an effective sensing area of 200 µm x 200 µm. The new bridge sensor is fully characterized at a frequency of 770 MHz and demonstrates a reliable and continuous detection of 4.5-µm iron-oxide magnetic beads over time periods longer than 30 min, appreciably longer than previously reported works