Principal Investigator: Professor Laneman

AWaRE REU Researcher: Nathan Jensen, Brigham Young University

Other Contributors: Xiwen Kang and John Morris

 

Project Summary:

The Citizens Broadband Radio Service (CBRS), currently targeting a radio frequency (RF) band centered around 3.5 GHz, represents a breakthrough in wireless technology and policy in the United States. For the first time, widespread commercial cellular networks based upon LTE technology will intelligently utilize RF spectrum that has otherwise been exclusively reserved for government systems like Navy radars. As RF spectrum becomes more crowded, and sharing spectrum among very different commercial and government systems becomes the norm, wireless system engineers need to build radios and network services that are much more context-aware and collaborative compared to current designs, basically redesigning such systems from the ground up to be more resilient to interference in congested environments.

To address problems in this space, our team has been developing prototypes, models, and algorithms for what is being called a collaborative intelligent radio system (CIRS). A CIRS needs to be able to sense what is going on in the RF spectrum in and around its intended band of operation, and then adaptive its transmission formats and receiver signal processing algorithms accordingly. Our radio prototypes are based upon software-defined radio (SDR), with which our team has extensive experience. Student projects involve learning how to use and develop for the prototyping platform, designing and implementing a set of new features, and testing and demonstrating those features to the group.

Finding:

Modern communication networks rely heavily on wireless technology which demands a reliable link be established between the sender and receiver of a transmission. A tremendous deal of largely successful research has been performed to increase the data rates achievable via wireless communication. However, very little research exists addressing the issues of maintaining link quality in the presence of antagonistic signal sources. Congested and contested networks are becoming increasingly prevalent issues. We are creating an upper level university course which will expose these to students, thus enabling them to engineer communication networks capable of maintaining link quality in these adverse conditions. The lab for this class involves exposing the students to the various components and signal processing techniques required for building a solid radio transmitter and receiver system. Most recently, we upgraded the radio hardware to include tunable phase locked-loops serving as the local oscillators, active mixers for the modulators and demodulators, and fully differential amplifier drivers supporting dual channel operation. The use of these various integrated circuits- some of which operate at radio frequencies- involves careful circuit design to maintain system integrity and flexibility. Furthermore, combining the various hardware components to build a functional radio is far from trivial, and therefore extensive unit and system testing was performed to determine system performance. Finally, various signal processing techniques were utilized to ensure a robust and high performing communication network. The second version of the course hardware kit has been finalized, allowing continuous streaming over a wireless link to be realized utilizing the homodyne radio architecture.

Principal Investigator: Professor O’Sullivan

AWaRE REU Researcher: Anuj Gajjar, Northeastern University

Other Contributors: Alicia Wei

 

Project Summary:

Despite the explosive growth in the development of wearable and implantable sensors for monitoring health and personal wellness, there are currently no viable sensor technologies that can sense targets deep within the human body. Current sensors are limited to sensing cutaneous or shallow subcutaneous tissue volumes, have limited functionality, or are simply too large and obtrusive. This prevents their use in some of the most impactful areas of medicine including monitoring solid tumors, simultaneous deep brain sensing and stimulation, and monitoring diseases of the internal organs. The long-term goal of this project is to develop an extensible microimplant platform that can ultimately be placed anywhere in the human body and provide sensitivity to multiple biomolecular targets continuously and in real-time. This project entails sensor design, modeling (mechanical and functional), and prototyping of wireless microimplants using advanced manufacturing processes.

Finding:

Breast tissue markers are tiny radiologically-visible grain-sized implants which are routinely implanted into suspicious breast lesions during biopsy procedures. These “breast clips” enable clinicians to radiologically locate breast lesions and group diseased areas for more precise monitoring. We are developing similarly-sized “smart” breast clips that can provide real-time information of a tumor to optimize treatment and extend survival. These smart clips consist of hyperspectral optical sources, photodetectors, and wireless power receiver and communication circuitry. These hyperspectral sources detect changes in concentrations and chemical states of three biomarkers: hemoglobin (oxygenated and deoxygenated), water (protein-bound or free), and lipids (saturated or unsaturated), which are directly related to tumor composition, metabolism, and vascularity. Such biomarkers can also predict a pathologic complete response (pCR) to chemotherapy. 

The smart breast clip performs this molecular sensing of tumor composition and hemodynamics via two microchip vertical-cavity surface-emitting lasers (VCSELs) covering the optical bandwidth (visible and near-infrared light) used to measure the above biomarkers. The implant also includes an analog front end to control the VCSELs and photodetectors, a receiver coil and impedance matching and rectification circuitry for wireless power transfer, as well as load-modulation of the RF power field for wireless communication. All sensor components and circuitry are integrated into a single printed circuit board sized to standard syringe needle sizes for in vivo implantation. 

To enable the final development aim of preclinical evaluation of the device, the accuracy, precision, dynamic range, stability, and tissue depth range must be well characterized. This characterization involves simulating the optical performance of the sensor, profiling the power performance of the VCSELs, profiling the response of the sensor’s photodetectors, and testing performance in an optical and electromagnetic phantom. In this poster, we describe our work to enable repeatable characterization of smart breast clips. 

The first goal was to perform Monte-Carlo-based tissue optical simulations of the device to obtain metrics about the overall expected optical performance of the breast clip. The second goal of this work was to automate a characterization procedure for the breast clip, which involved reading measurements from various external detectors that characterize laser and photodetector performance, as well as controlling the analog front end within the sensor. Using a combination of Python and C++ programming, a modular software system was built to achieve both goals, and thus provide progress toward preclinical evaluation of the breast clip.

Principal Investigator: Professor Striegel

AWaRE REU Researcher: Junji (John) Shen, Valparaiso University

Contributors: Alamin Mohammed and Shangyue Zhu

 

Project Summary:

Traditionally, most network measurement tools such as Speedtest.net and others measure the network in an isolated manner. Further, while peak speed can be interesting, it often fails to capture all of the dynamics of modern wireless networks. The focus of this project is to study the interplay of how sharing various pieces of network information between apps and wireless devices can lead to improved network understanding and performance.

Finding:

The current free analysis of Internet access performance like Speedtest.net measures the data throughput and latency by sending larger and larger data flows until the network fails to handle additional traffic with the process generally taking on the order of 10-20 seconds. The advantage of this approach is that it is easy to implement and can accurately measure the achievable throughput of the network. However, during the Speedtest.net measuring process, tens of megabytes of data can be sent between devices and the network can be congested for quite some time, resulting in a large cost in terms of both mobile device energy and link utilization. For instance, for a single test on a link of 10 Mb/s, the resulting test will use approximately 20 MB of data making it difficult to justify running tests longitudinally to measure network performance. Moreover, the majority of the users do not necessarily need to know the exact bandwidth of the network, rather all the users care about is if the network can handle their normal online activities. Therefore, a method that can reduce the data being transmitted with reduced bandwidth and shorter times could be a significant improvement.  The focus of this work is to explore the extent that QUIC and the Go language, a new variant for network transfers and a newly emergent language for concurrency, could help advance existing works in a more scalable and effective manner towards measuring network performance.

Principal Investigator: Professor Lin

AWaRE REU Researcher: Dillon Falkinburg, University of Nebraska – Lincoln

Contributors: Vincent Kurtz

 

Project Summary:

This REU project aims to develop a team of robotic systems that can accomplish complex team missions even in the face of uncertain and dynamic environments. Applications that motivate this project include, but not limited to, emergency response, future manufacturing systems, and service robots. In this REU project, we will touch topics on both hardware/software development and theoretical/algorithm design, such as communication-aware coordinated motion planning, sensing, task planning through formal methods, a counterexample-guided synthesis which combines logic inference with optimization.

Finding:

Developed algorithms to synthesize robust trajectories, and to adapt the trajectories during run-time to deal with unknown obstacles or other agents in the environment. Implemented these algorithms in real robotic platforms, such as Pioneer 3AT/3DX and Baxter.

Principal Investigator: Professor Joshi

AWaRE REU Researcher: Colton Kammes, University of Notre Dame

Other Contributors: Mark Horeni and Tanner Waltz

 

Project Summary:

Due to tight on-die integration in low-cost, low-power wireless modules, digital and mixed-signal subsystems are often placed very close to each other. Noise coupling from the digital system is often indicative of the computations being performed and thus leaks information to the outside world. We would like to characterize this leakage and see what can we infer about the computations occurring inside the chip using only the signals leaking outside.

Finding:

System-on-Chips (SoCs) are integrated circuits that integrate multiple components of a computer.  These devices are typically used in IoT and Smartphone applications and typically have radios in close proximity to the other components such as the processor and memory. Due to the proximity, CPU and  Memory activity can propogate through the radio and leak data wirelessly through RF communications. When encryption (such as AES-128) is occurring on the chip, leakage is transmitted which can be used to determine the encryption key through template attack algorithms like canonical correlation analysis.  Such algorithms require many traces to attack a single key, but a Multi-Layer Perceptron (MLP) can attack multiple keys with fewer traces. To train the MLP, a large, clean, and consistent dataset must be collected. After training, an MLP can collect a single trace from a target and recover information such as an encryption key. Single trace MLP attacks are a vast improvement to classic algorithms as they are faster and require significantly less data at the time of attack.

Principal Investigator: Professor Fay

AWaRE REU Researcher: Lauren Stark, University of Notre Dame

Other Contributor: Nivedhita Venkatesan

 

Project Summary:

GaN-based transistors are increasingly attractive for applications across the microwave and millimeter-wave frequency range, including power amplifiers, low-noise amplifiers, switches for reconfigurable RF systems, and more. This project includes measuring the performance of several GaN transistor designs (including DC measurement, low-frequency AC, and high-frequency on-wafer characterization) and developing models suitable for computer-aided circuit design of these transistors from the measured characteristics. Comparisons of different models (e.g. ASM-HEMT, Angelov, etc.) and their respective abilities to capture key device performance features are included to evaluate the suitability of the models for different circuit applications.

Finding:

Transistors are the workhorse device that underpins all modern electronics.  While silicon-based transistors have come to dominate in digital applications due to their scalability and high degree of integration, for wireless communications and RF applications, silicon devices have limitations in terms of their output power, frequency range, and noise performance. One attractive solution to this problem that is being explored is the use of Gallium Nitride (GaN) based transistors. Because of the material properties of GaN (larger band gap, higher electron mobility) GaN transistors have the ability to function at a higher power levels, higher frequencies, and at higher temperatures than silicon.  However, an open question is what are the ultimate limits of GaN transistors, and how can they best be used in circuits? To address this question, a nonlinear model (suitable for circuit design) is being extracted based on measured electrical characteristics of devices.  Example research-grade GaN transistors, with gate lengths of approximately 50 nm and gate periphery of 37.5 microns, were placed under a microscope on a probe station.  Two microwave-style probes were used (one on each side) that allowed different voltages to be applied to the device, and the resulting currents to be measured. The outcome of this test created multiple data sets that quantify the device’s response to these applied measurements. 

Principal Investigator: Professor Chisum

AWaRE REU Researcher: James Ernst, Valparaiso University

Other Contributors: Nicholas Estes, Nicolas Garica, and Wei Wang

 

Project Summary:

Phased arrays have proven to be an enabler for high-performance communications and sensing in the sub-6 GHz bands. They enable high-gain links to individual remote radios which can be tracked in space to achieve high data rates, enable spatial reuse, and even provide location-aware applications. This technology was initially developed in the defense sector at great cost and with significant power consumption. However, commercial-off-the-shelf (COTS) DACs and ADCs have seen a dramatic reduction in cost and power consumption and a wide range of integrated RF components in the sub-6 GHz bands have become available. These trends have enabled the technology to transition to the commercial sector with great success.

More recently the same technology was transitioned to the millimeter-wave (MMW) bands (>30 GHz) to enable 5G MMW communications with data rates beyond 1 Gbps. Unfortunately, the technology (data converters and radio components) did not scale well so the 5G MMW phased arrays consume extremely high power. In fact, the first generation of 5G MMW-enabled mobile phones were only capable of operating at Gbps rates for ~10 minutes before the battery was drained.

Instead of taking technologies that worked well at low-frequencies and moving them up in frequency, an alternative approach is to take technologies which natively work at high frequencies such as lens antennas, and modify them to provide the desired functionality (high-speed beam-scanning and multi-beam apertures) for 5G MMW.

The purpose of this research project is to explore the length to which switch-beam lens antennas can provide the most important features and capabilities of a phased array but at a fraction of the cost and power. This project will build off of the MMW lens antenna demonstrations from the PIs research group and will include theoretical electromagnetic antenna modeling as well as linear systems analysis (especially beam-forming theory and beam-synthesis methods from field theory). In addition, the student will use the PI’s measurement laboratory and near-field antenna range to demonstrate phased-array-fed lens antennas using state-of-the-art beamformer integrated circuits.

Finding:

5G and satellite-based internet systems both types of systems rely upon beam-scanning antennas while in the millimeter-wave bands to allow target tracking and to close links in real time. The traditional solution for antennas with beam scanning capabilities is a phased array that combines potentially 1000’s of antenna elements, each element has its own active electronics, so synthesizing beams is very costly and consumes large amounts of power. In our research, we are exploring hybrid solutions of widely spaced antenna arrays combined with low-cost lens antennas to achieve similar performance as a traditional phased array, but at a fraction of the active elements. In addition, in our design, less than 10% of the elements are active at a  time which dramatically reduces dynamic power consumption. Our main objective is to characterize a hybrid lens/array system to find the maximum performance for the number of elements used at different spacings. We have measured the radiative electric far-field for each antenna feed in a virtual array using a planar near-field scanner for our hybrid system and 27  GHz and analyzed the possible beams for such a system. The work demonstrates that this method reduces the number of feeds by more than a factor of two while still being able to produce acceptable beam scanning capabilities. Leaving us with a promising method for commercial applications which require millimeter-wave beam scanning.

 

Project Summary:

Notre Dame is involved in the development and implementation of target detection and identification concepts for radar applications. Evaluation of these concepts will be assessed experimentally using software-defined radar platforms. The research for the undergraduate student is expected to involve participation in experiments to evaluate one or more radar concepts, depending on project needs. The student will have opportunities to contribute to various facets of the research, including field tests, data analyses, and documentation.

Student’s Role:

Research opportunities for the undergraduate student will involve one or more topics associated with radar, including advanced radar architectures, distributed radar systems, and novel target characterizations. The undergraduate students will participate in radar literature surveys, radar subsystem implementations (in Matlab), field experimentation, and data analysis. The student is expected to provide research products in the form of slides and weekly status reports. The undergraduate students will work on a team 4 of researchers that includes the PI, research engineers, and graduate students. The student will gain exposure to radar concepts as well as to state-of-the-art equipment, including a software-defined radios, a custom $700K multi-antenna transceiver system, and two 9-ton field research vehicles that are used in experimentation.

Project Summary:

Novel transistor designs for improved linearity in GaN-based FETs are being explored for their potential to improve dynamic range in mm-wave low noise amplifiers (LNAs). This project includes device design, modeling, fabrication, and characterization of devices, as well as design of low-noise amplifiers (based on the extracted models) and comparison with designs based on conventional transistors in order to fully understand the potential benefits and any associated design trade-offs for mm-wave receiver applications.

 

Student’s Role:

Student involvement in this project can take several forms; focus on one particular aspect (e.g. device design, characterization, LNA design) is anticipated. For example, for device design work student would perform physics-based TCAD simulations of candidate designs, and optimize the device structure for best input IP3 and gain performance. For characterization, fabricated devices will be characterized on-wafer using nonlinear vector network analysis and on-wafer noise-parameter measurements in order to experimentally characterize the nonlinearities as well as noise figure and noise parameters. LNA design will include design of mm-wave LNA blocks (e.g. single-stage amplifier with reactive matching) to form the basis of comparative studies between new and conventional device designs.

Principal Investigator: Professor Striegel

AWaRE REU Researcher: Christopher Ferguson, Trine University

Other Contributor: Stephen Mattingly

 

Project Summary:

Beyond serving as an essential part of connectivity for our various smart devices, WiFi also can be helpful in providing environmental context such as the likely presence of people using devices, the density of devices being used, and changes in the nearby environment. The focus of this project is to explore the extent to which vehicle-mounted WiFi sensing could help better discern important environmental cues that are of interest to researchers and government entities.

Finding:

One way of limiting the spread of the ongoing COVID-19 pandemic is reducing contact between infected and uninfected individuals. “Contact tracing”, in which people provide a summary of interpersonal interactions via clinician interview, allows authorities to monitor the spread of the disease. Using this information, authorities can inform individuals of their possible exposure, allowing them to restrict their interactions and avoid further spread.

The N-Distance project aims to create a system using passive and privacy sensitive sensors to achieve a similar effect for a localized area, such as a college campus. This information is utilized in a visual format to allow easy identification of areas that have a high risk of spreading disease based on proximity between individuals, and to identify these patterns historically and in real time, allowing for timely intervention by college officials. In addition, this tool provides individuals the ability to assess risk and modify behavior accordingly, e.g. seeking out a less crowded area to study in.

This system is based on phone location and Bluetooth sighting data gathered from participants who install an app and carry a beacon. By collecting this data, the N-Distance system is able to generate a heatmap of roughly when and where interactions occur on campus. Because data is collected passively and with an emphasis on privacy, the system may reduce the need for self-reporting that may interfere with privacy.

Principal Investigator: Professor Pratt

Other Contributors: Luis Perez, Rob Kossler

AWaRE REU Researcher: Patrick Callaghan, Community College of Allegheny County

Project Description: Notre Dame is involved in the development and implementation of target detection and identification concepts for radar applications. Evaluation of these concepts will be assessed experimentally using software-defined radar platforms. The research for the undergraduate student is expected to involve participation in experiments to evaluate one or more radar concepts, depending on project needs. The student will have opportunities to contribute to various facets of the research, including field tests, data analyses, and documentation.

Finding: Monopulse antennas are used in radar to track targets and are also used passively in radio astronomy and in electronic support measures (ESM). In radar applications, monopulse radar is favored for its ratio-based processing—which offers some resilience to jamming—and it conventionally involves single-polarization implementations.

Dual-polarized monopulse concepts, however, are beginning to appear in literature, primarily as a means to augment the monopulse radar’s ability to counter jamming. One example is the paper by Zhang and Pan (“Adaptive Countering Technique for Angle Deception Based on Dual Polarization Radar Seeker”) which deals with monopulse methods enabled by dual-polarization radar architectures to counter angle jamming.

Our goal in the summer research project was to work with data associated with a fabricated monopulse antenna in various tasks, including 1) synthesizing monopulse antenna patterns; 2) implementing monopulse signal processing techniques; 3) modeling and analyzing system responses to simplistic target scenarios, and finally, including dual-polarized methods discussed in literature that aim to improve jamming-resilience.

To work towards these goals, antenna pattern modeling based on recently fabricated dual-polarized monopulse antennas was achieved using an electromagnetic modeling tool called FEKO. The resulting antenna pattern characterizations were exported to MATLAB where sum and difference antenna patterns based on linear combinations of element patterns were synthesized and compared with the FEKO estimates. Additionally, monopulse radar signal processing algorithms were implemented and applied to simplistic single- and two-target scenarios. Plans are to integrate methods from literature to investigate performance in the presence of jamming.

Principal Investigator: Professor Laneman

Other Contributors: Lihua Wan, Miaomiao Hu

AWaRE REU Researcher: Isaac Carrasco, University of New Mexico

Project Description: The Citizens Broadband Radio Service (CBRS), currently targeting a radio frequency (RF) band centered around 3.5 GHz, represents a breakthrough in wireless technology and policy in the United States. For the first time, widespread commercial cellular networks based upon LTE technology will intelligently utilize RF spectrum that has otherwise been exclusively reserved for government systems like Navy radars. As RF spectrum becomes more crowded, and sharing spectrum among very different commercial and government systems becomes the norm, wireless system engineers need to build radios and network services that are much more context-aware and collaborative compared to current designs, basically redesigning such systems from the ground up to be more resilient to interference in congested environments.

To address problems in this space, our team has been developing prototypes, models, and algorithms for what is being called a collaborative intelligent radio system (CIRS). A CIRS needs to be able to sense what is going on in the RF spectrum in and around its intended band of operation, and then adaptive its transmission formats and receiver signal processing algorithms accordingly. Our radio prototypes are based upon software-defined radio (SDR), with which our team has extensive experience. Student projects involve learning how to use and develop for the prototyping platform, designing and implementing a set of new features, and testing and demonstrating those features to the group.

Finding: Current pedagogical techniques of understanding communication systems and hands-on implementations of radio systems are on the decline as more teaching institutions begin to hide key elements of communication systems. One such key element would be the physical radio path which up-converts and down-converts a radio signal. The importance of student’s comprehension of these key elements will give them the insight to diagnose and find solutions to problems that lay at the core of communications systems.

The goal of this project is to devise curriculum and a laboratory setup that is low-cost and packaged to be accessible to academic and government institutions. The research this summer is determining and testing the laboratory setup and materials for the course which consists of a radio path and an ADALM 2000, which is a device that is able to send and receive signals among other features.

This project task is to utilize On-Off Keying (OOK) modulation to modulate a signal and send it out through an ADALM 2000, then receive a signal through the ADALM 2000, and demodulate it in order to get the original signal that was sent out. This will allow the students to see their signal being sent out and received which will improve the student’s understanding of how radio systems work. This combined with the theory and laboratories of the course will improve the student’s comprehension of an overall communication system.