A review of millimeter-wave radar research

With the rapid development of scientifi c research and the maturity of technology, millimeter-wave radar has become the focus of research in industrial production, national defense construction and other fi elds because of its high precision and high applicability. This paper introduces the application fields and algorithm development of millimeter wave radar, expounds the common application scenarios of millimeter wave radar, and gradually elaborates the development and update of radar detection algorithm, on this basis, the new research direction of millimeter wave radar and the improved algorithm idea of FMCW millimeter wave radar detection algorithm are proposed

Millimeter wave radar for SLAM applications

Lo scopo di questa tesi è quello di introdurre la tecnologia radar ad onde millimetriche applicata a problemi di mapping e di localizzazione in modo da investigare la fattibilità del recente concetto di "personal radar". Più specificatamente, può essere inteso come una caratteristica futura degli apparecchi mobili per la stima delle mappe degli ambienti interni sfruttando le tecnologie di comunicazione già presenti, avendo così la possibilità di creare applicazioni di localizzazione che non necessitano di infrastrutture ad-hoc. Il personal radar scansiona automaticamente l'ambiente circostante e mediante l'utilizzo di antenne colleziona le risposte provenienti dall'ambiente ad ogni direzione di scansione. Successivamente analizzando i dati collezionati il personal radar è in grado di dedurre la mappa dell'ambiente. Al momento le tecnologie più usate sono quella lidar o quella camera-based ma sono solitamente tecnologie più costose e che richiedono supporti meccanici e perfette condizioni di visibilità dell'ambiente. Per queste ragioni è interessante esplorare la tecnologia radar ad onde millimetriche. Questa teconologia infatti offre la possiilità di impacchettare un numero elevato di antenne in un piccolo spazio e quindi di realizzare diagrammi di radiazione molto stretti alle spese di una degradazione delle perfomance. Per queste ragioni è stato deciso di suddividere la tesi nei seguenti capitoli. Nel primo capitolo viene fornita una breve spiegazione della teoria radar con attenzione particolare alla tecnologia (FMCW) del dispositivo utilizzato. Nel secondo capitolo viene fornita una analisi della teoria dello SLAM con un approfondimento sulla teoria SLAM basata su grafi. Dopodichè è presente una analisi del dispositivo utilizzato. Nel quarto capitolo vengono descritti gli algoritmi sviluppati e i motivi per cui sono stati necessari e infine nel capitolo finale vengono riportati i risultati finali con le relative considerazioni

Walking Step Monitoring with a Millimeter-Wave Radar in Real-Life Environment for Disease and Fall Prevention for the Elderly

We studied the use of a millimeter-wave frequency-modulated continuous wave radar for gait analysis in a real-life environment, with a focus on the measurement of the step time. A method was developed for the successful extraction of gait patterns for different test cases. The quantitative investigation carried out in a lab corridor showed the excellent reliability of the proposed method for the step time measurement, with an average accuracy of 96%. In addition, a comparison test between the millimeter-wave radar and a continuous-wave radar working at 2.45 GHz was performed, and the results suggest that the millimeter-wave radar is more capable of capturing instantaneous gait features, which enables the timely detection of small gait changes appearing at the early stage of cognitive disorders

Universal Millimeter-Wave Radar Front End

A quasi-optical front end allows any arbitrary polarization to be transmitted by controlling the timing, amplitude, and phase of the two input ports. The front end consists of two independent channels horizontal and vertical. Each channel has two ports transmit and receive. The transmit signal is linearly polarized so as to pass through a periodic wire grid. It is then propagated through a ferrite Faraday rotator, which rotates the polarization state 45deg. The received signal is propagated through the Faraday rotator in the opposite direction, undergoing a further 45 of polarization rotation due to the non-reciprocal action of the ferrite under magnetic bias. The received signal is now polarized at 90deg relative to the transmit signal. This signal is now reflected from the wire grid and propagated to the receive port. The horizontal and vertical channels are propagated through, or reflected from, another wire grid. This design is an improvement on the state of the art in that any transmit signal polarization can be chosen in whatever sequence desired. Prior systems require switching of the transmit signal from the amplifier, either mechanically or by using high-power millimeter-wave switches. This design can have higher reliability, lower mass, and more flexibility than mechanical switching systems, as well as higher reliability and lower losses than systems using high-power millimeter-wave switches

Line of sight visibility analysis for foreign object debris detection system

It is challenging to monitor busy airports' runway through visual inspection to precisely detect foreign object debris. Currently, many technologies for the detection of foreign object debris are available. It has been investigated that millimeter-wave radar technology's detection capability can be one of the most effective techniques for detecting foreign object debris as it is weather-resilient. However, the positioning and height of a millimeter-wave radar pole covering the runway area, considering the existing runway infrastructure, are challenging. The task involves finding the appropriate placement and optimum height. This paper presents a novel method of line of sight visibility for placement and height of radar pole using human factor research to ensure that each point on the runway is visible from various heights of the millimeter-wave radar pole to the runway locations. Kuala Lumpur International Airport, Malaysia runway 32L/14R, has used a case study to test the visibility analysis. The visual analytic test's successful results for different millimeter-wave radar pole locations and viewing heights under a visible and invisible line of sight conditions on the runway have been verified in the field experiment

Contactless Electrocardiogram Monitoring with Millimeter Wave Radar

The electrocardiogram (ECG) has always been an important biomedical test to diagnose cardiovascular diseases. Current approaches for ECG monitoring are based on body attached electrodes leading to uncomfortable user experience. Therefore, contactless ECG monitoring has drawn tremendous attention, which however remains unsolved. In fact, cardiac electrical-mechanical activities are coupling in a well-coordinated pattern. In this paper, we achieve contactless ECG monitoring by breaking the boundary between the cardiac mechanical and electrical activity. Specifically, we develop a millimeter-wave radar system to contactlessly measure cardiac mechanical activity and reconstruct ECG without any contact in. To measure the cardiac mechanical activity comprehensively, we propose a series of signal processing algorithms to extract 4D cardiac motions from radio frequency (RF) signals. Furthermore, we design a deep neural network to solve the cardiac related domain transformation problem and achieve end-to-end reconstruction mapping from RF input to the ECG output. The experimental results show that our contactless ECG measurements achieve timing accuracy of cardiac electrical events with median error below 14ms and morphology accuracy with median Pearson-Correlation of 90% and median Root-Mean-Square-Error of 0.081mv compared to the groudtruth ECG. These results indicate that the system enables the potential of contactless, continuous and accurate ECG monitoring

Non-Contact Vital Sign Detection Using mm-Wave Radar

Vital Sign detection using radars has been a rising technology in the fields of healthcare, security, and military purposes. Typically, radars used for these tasks operate at lower frequencies due to their low cost and and the ability to detect behind obstacles, such as walls or undre debris. However, this leads to an overall large system as the lower the frequency of operation, the larger the size of the antennas. The system size increases when multiple antennas are used for subject localization. But, with the development of millimeter- wave radars and Antenna-on-Package (AoP) solutions, a more compact and portable radar is possible. In this thesis, a commercial, compact, and portable millimeter wave radar operating at 60 GHz is used to detect the vital signs of subjects. With the use of direction of arrival, beamforming, and frequency tracking, the millimeter wave radar is able to accurately detect the heart rate and respiration rate of subjects with high accuracy. Experiments are performed involving detection with varying distances, detection through drywall, and for a single or even multiple subjects