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This paper presents an mmWave FMCW radar that can achieve sub-centimeter-scale range resolution at 14- GHz chirp-bandwidth while maintaining the radar range beyond 50 meters. To meet the requirements on power efficiency, chirp linearity, and signal-to-noise ratio (SNR), a phase-locked steppedchirp FMCW radar architecture is introduced. Specifically, a fully integrated radar transceiver comprising an interleaved frequency-segmented phase-locked transmitter and a segmented receiver architecture with high sensitivity is presented. The proposed design addresses the limitations of conventional typeII phase-locked loops (PLLs) in extending the radar bandwidth across multiple sub-bands with identical chirp profiles. Fabricated in a 22nm FD-SOI technology, the prototype chip comprises two sub-bands with 14 GHz of free-running bandwidth and 10 GHz of phase-locked bandwidth. The system achieves -101.7 dBc/Hz phase noise at 1 MHz offset, 8 dBm of effective isotropic radiated power (EIRP), 10 dB noise figure (NF), and 362.6 mW collective power consumption of transmitter and receiver arrays. 

Abstract Objective.Invasive brain–computer interfaces (BCIs) have shown promise in restoring motor function to those paralyzed by neurological injuries. These systems also have the ability to restore sensation via cortical electrostimulation. Cortical stimulation produces strong artifacts that can obscure neural signals or saturate recording amplifiers. While front-end hardware techniques can alleviate this problem, residual artifacts generally persist and must be suppressed by back-end methods.Approach.We have developed a technique based on pre-whitening and null projection (PWNP) and tested its ability to suppress stimulation artifacts in electroencephalogram (EEG), electrocorticogram (ECoG) and microelectrode array (MEA) signals from five human subjects.Main results.In EEG signals contaminated by narrow-band stimulation artifacts, the PWNP method achieved average artifact suppression between 32 and 34 dB, as measured by an increase in signal-to-interference ratio. In ECoG and MEA signals contaminated by broadband stimulation artifacts, our method suppressed artifacts by 78%–80% and 85%, respectively, as measured by a reduction in interference index. When compared to independent component analysis, which is considered the state-of-the-art technique for artifact suppression, our method achieved superior results, while being significantly easier to implement.Significance.PWNP can potentially act as an efficient method of artifact suppression to enable simultaneous stimulation and recording in bi-directional BCIs to biomimetically restore motor function.