Adhoc mobile power connectivity using a wireless power transmission grid

Wireless charging of devices has significant outcomes for mobile devices, IoT devices and wearables. Existing technologies consider using Point to Point type wireless transfer from a transmitter Tx (node that is sending Power) to a receiver Rx (node that receives power), which limits the area of coverage for devices. As a result, existing systems are forced to use near field coupling to charge such devices. Fundamental limitation is also that such methods limit charging to a small hotspot. In partnership with Wireless Electrical Grid LANs (WiGL pronounced “wiggle”), we demonstrate patented Ad-hoc mesh networking method(s) to provide wireless recharging at over 5 feet from the source, while allowing significant lateral movement of the receiver on the WiGL (Wireless Grid LAN or local area network). The transmitter network method leverages a series of panels, operating as a mesh of transmitters that can be miniaturized or hidden in walls or furniture for an ergonomic use. This disruptive technology holds the unique advantage of being able to provide recharging of moving targets similar to the cellular concept used in WiLAN, as opposed to prior wireless charging attempts, which only allow a hotspot-based charging. Specifically, we demonstrate the charging of a popular smartphone using the proposed system in the radiating near field zone of the transmitter antennas, while the user is free to move in the space on the meshed network. The averaged received power of 10 dBm is demonstrated using 1W RF-transmitter(s), operating in the 2.4 GHz ISM band. The proposed hardware consists of antennas arrays, rectennas, power management and USB 2.0 interfaces for maintaining a voltage between 4.2 and 5.3 V and smooth charging. We also show extending the wireless grid coverage with the use of multiple transmitting antennas, and mechanical beam-steering even further an increased coverage using the proposed system

A Passive STAR Microwave Circuit for 1-3 GHz Self-Interference Cancellation

Simultaneous transmit and receive (STAR) allows full-duplex operation of a radio, which leads to doubled capacity for a given bandwidth. A circulator with high-isolation between transmit and receive ports, and low-loss from the antenna to receive port is typically required for achieving STAR. Conventional circulators do not offer wideband performance. Although wideband circulators have been proposed using parametric, switched delay-line/capacitor, and N-path filter techniques using custom integrated circuits, these magnet-free devices have non-linearity, noise, aliasing, and switching noise injection issues. In this paper, a STAR front-end based on passive linear microwave circuit is proposed. Here, a dummy antenna located inside a miniature RF-silent absorption chamber allows circulator-free STAR using simple COTS components. The proposed approach is highly-linear, free from noise, does not require switching or parametric modulation circuits, and has virtually unlimited bandwidth only set by the performance of COTS passive microwave components. The trade-off is relatively large size of the miniature RF-shielded chamber, making this suitable for base-station side applications. Preliminary results show the measured performance of Tx/Rx isolation between 25-60 dB in the 1.0-3.0 GHz range, and 50-60 dB for the 2.4-2.7 GHz range.Comment: 4 figures, 4 page

A low frequency mechanical transmitter based on magnetoelectric heterostructures operated at their resonance frequency

Magneto-elasto-electric (ME) coupling heterostructures, consisting of piezoelectric layers bonded to magnetostrictive ones, provide for a new class of electromagnetic emitter materials on which a portable (area ~ 16 cm 2 ) very low frequency (VLF) transmitter technology could be developed. The proposed ME transmitter functions as follows: (a) a piezoelectric layer is first driven by alternating current AC electric voltage at its electromechanical resonance (EMR) frequency, (b) subsequently, this EMR excites the magnetostrictive layers, giving rise to magnetization change, (c) in turn, the magnetization oscillations result in oscillating magnetic fields. By Maxwell’s equations, a corresponding electric field, is also generated, leading to electromagnetic field propagation. Our hybrid piezoelectric-magnetostrictive transformer can take an input electric voltage that may include modulation-signal over a carrier frequency and transmit via oscillating magnetic field or flux change. The prototype measurements reveal a magnetic dipole like near field, demonstrating its transmission capabilities. Furthermore, the developed prototype showed a 10 4 times higher efficiency over a small-circular loop of the same area, exhibiting its superiority over the class of traditional small antennas

Hardware Accelerated Fast FDTD of Time Dependent Maxwell’s Equations on Xilinx RF SoC

Electromagnetics, which govern the fields of wireless communications, radar, and remote sensing, are fully described using four first-order PDEs known as Maxwell’s Equations. The finite-difference time-domain (FDTD) algorithm invented by Yee in 1966 operates on a discrete space-time staggered grid-pair for the electric and magnetic fields, and solutions are obtained via leapfrog update equations. The field of computational electromagnetics makes extensive use of the FDTD algorithm for modeling involving various types of antennas, microwave filters, circuits, aerospace vehicles, and wireless systems. For accurate and dispersion-less solution, the discretization of the spatial and temporal variables require a high degree of over-sampling that is much higher than what is demanded by the Nyquist Sampling Theorem, in order for the discrete domain update equations to represent the behavior of a continuous linear PDE system. The highly-oversampled nature of FDTD results in high computational complexity and therefore long execution times on high-performance computing systems. Hardware acceleration is a technique to accelerate the computation of FDTD using application-specific integrated digital processor arrays that are custom designed for implementing FDTD without using any software at all. The hard-wired parallel computation allows very good acceleration compared to state-of-art computing solutions based on high-performance compute servers, GPU realizations, and cloud computing techniques. The talk reports on a hardware accelerator that supports real-time operation on a Xilinx RF SoC device. Comparison with GPUs are provided (interim results show better than x100)

Design and Development of Dual Polarized, Stacked Patch Antenna Element for S-Band Dual-Pol Weather Radar Array

Dual-polarized weather radars are gaining popularity due to their promise of accurate and faster weather prediction. This work presents the design of a dual-polarized, patch antenna element operating in the band 2.7 GHz - 3.0 GHz, with 30 dB isolation between the ports, which can be utilized for a dual-pol weather radar array. To characterize current design for weather radar, recently published parameters called W-parameters, have been evaluated for the demonstrated antenna hardware. Certain other properties of these W-parameters have also been studied. In the process of reaching a low cross-pol design, basic mechanism of cross-polar radiation in rectangular patch antennas has also been analyzed using a novel strategy of near-field analysis. This near field analysis has been further applied on slotted antennas to understand their radiation properties. New strategy of understanding the radiation properties based on the near-field provides visualization based understanding of the radiation mechanism in small antennas

Generation of vector vortex wave modes in cylindrical waveguides

Abstract In this paper, we propose a method to generate Vector Vortex Modes (VVM) inside a metallic cylindrical waveguide at microwave frequencies and demonstrate the experimental validation of the concept. Vector vortex modes of EM waves can carry both spin and orbital angular momentum as they propagate within a tubular medium. The existence of such waves in tubular media can be beneficial to wireless communication in such structures. These waves can carry different orbital angular momentum and spin angular momentum, and therefore, they feature the ability to carry multiple orthogonal modes at the same frequency due to spatial structure of the phase and polarization. In essence, high data rate channels can be developed using such waves. In free space, Orbital Angular Momentum carrying vortex waves have beam divergence issues and a central field-minima, which makes these waves unfavorable for free space communication. But vector vortex mode waves in guided structures do not suffer from these drawbacks. This prospect of enhancement of communication spectrum in waveguides provides the background for the study of vortex wave in circular waveguides. In this work, new feed structures and a radial array of monopoles are designed to generate the VVM carrying waves inside the waveguide. The experimental findings on the distribution of the amplitude and phase of the electromagnetic fields inside the waveguide are presented and the relationship between the waveguide fundamental modes and VVMs are discussed for the first time. The paper also presents methods for varying the cutoff frequency of the VVMs by introducing dielectric materials in the waveguide

Generation of vector vortex wave modes in cylindrical waveguides

In this paper, we propose a method to generate Vector Vortex Modes (VVM) inside a metallic cylindrical waveguide at microwave frequencies and demonstrate the experimental validation of the concept. Vector vortex modes of EM waves can carry both spin and orbital angular momentum as they propagate within a tubular medium. The existence of such waves in tubular media can be beneficial to wireless communication in such structures. These waves can carry different orbital angular momentum and spin angular momentum, and therefore, they feature the ability to carry multiple orthogonal modes at the same frequency due to spatial structure of the phase and polarization. In essence, high data rate channels can be developed using such waves. In free space, Orbital Angular Momentum carrying vortex waves have beam divergence issues and a central field-minima, which makes these waves unfavorable for free space communication. But vector vortex mode waves in guided structures do not suffer from these drawbacks. This prospect of enhancement of communication spectrum in waveguides provides the background for the study of vortex wave in circular waveguides. In this work, new feed structures and a radial array of monopoles are designed to generate the VVM carrying waves inside the waveguide. The experimental findings on the distribution of the amplitude and phase of the electromagnetic fields inside the waveguide are presented and the relationship between the waveguide fundamental modes and VVMs are discussed for the first time. The paper also presents methods for varying the cutoff frequency of the VVMs by introducing dielectric materials in the waveguide