Circulant Shift-based Beamforming for Secure Communication with Low-resolution Phased Arrays

Millimeter wave (mmWave) technology can achieve high-speed communication due to the large available spectrum. Furthermore, the use of directional beams in mmWave system provides a natural defense against physical layer security attacks. In practice, however, the beams are imperfect due to mmWave hardware limitations such as the low-resolution...

A 2D Ultrasound Phased-Array Transmitter ASIC for High-Frequency US Stimulation and Powering

Ultrasound (US) neuromodulation and ultrasonic power transfer to implanted devices demand novel ultrasound transmitters capable of steering focused ultrasound waves in 3D with high spatial resolution and US pressure, while having a miniaturized form factor. Meeting these requirements needs a 2D array of ultrasound transducers directly...

InFocus: A spatial coding technique to mitigate misfocus in near-field LoS beamforming

Phased arrays, commonly used in IEEE 802.11ad and 5G radios, are capable of focusing radio frequency signals in a specific direction or a spatial region. Beamforming achieves such directional or spatial concentration of signals and enables phased array-based radios to achieve high data rates. Designing beams for millimeter wave and terahertz...

Physical Layer Defense against Eavesdropping Attacks on Low-Resolution Phased Arrays

Eavesdropping attacks are a severe threat to millimeter-wave (mmWave) networks that use low-resolution phased arrays. Although directional beamforming in mmWave phased arrays provides natural defense against eavesdropping, the use of low-resolution phase shifters induces energy leakage into unintended directions. This energy leakage can be...

5G SIW-Based Phased Antenna Array With Cosecant-Squared Shaped Pattern

In this article, a concept of a phased antenna array based on substrate integrated waveguide (SIW) technology for 5G base stations is proposed. The array has a cosecant radiation pattern in the vertical plane for uniform illumination in a sector area. The array itself consists of 16 SIW traveling wave subarrays of 12 slot-coupled microstrip...

An Integrated 2D Ultrasound Phased Array Transmitter in CMOS with Pixel Pitch-Matched Beamforming

Emerging non-imaging ultrasound applications, such as ultrasonic wireless power delivery to implantable devices and ultrasound neuromodulation, require wearable form factors, millisecond-range pulse durations and focal spot diameters approaching 100 μm with electronic control of its three-dimensional location. None of these are compatible...

Simulation of ultrasonic beam propagation from phased arrays in anisotropic media using linearly phased multi-Gaussian beams

Phased array ultrasonic testing is widely used to test structures for flaws due to its ability to produce steered and focused beams. The inherent anisotropic nature of some materials, however, leads to skewing and distortion of the phased array beam and consequently measurement errors. To overcome this, a quantitative model of phased array...

Phase-Only Control of Peak Sidelobe Level and Pattern Nulls Using Iterative Phase Perturbations

Minimization of the maximum sidelobe level for a given array geometry, amplitude distribution, and nulling sectors by phase-only adjustment of the element coefficients is studied. Nonlinear optimization problem for phase distribution is solved using a novel iterative convex optimization algorithm, which includes mutual coupling effects and...