Probabilistic Approach to Design of Large Antenna Arrays

2000 Mathematics Subject Classification: 78A50Recent advances in space exploration have shown a great need for antennas with high resolution, high gain and low sidelobe (SL) level. The last characteristic is of paramount importance especially for the Microwave Power Transmission (MPT) in order to achieve higher transmitting efficiency. In this concern statistical methods play an important role. Various probabilistic properties of a large antenna array with randomly, uniformly and combined spacing of elements are studied and especially the relationship between the required number of elements and their appropriate spacing from one part and the desired SL level, the aperture dimension, the beamwidth and transmitting efficiency from the other. We propose a new unified approach in searching for reducing SL level by exploiting the interaction of deterministic and stochastic workspaces of proposed algorithms, emphasizing on the distribution of the maximums of SL level. These models indicate any advantages with respect to sidelobes in the large area around the main beam. A new concept of designing a large antenna array system is proposed. Our theoretic study and simulation results clarify how to deal with the problems of sidelobes in designing a large antenna array, which seems to be an important step toward the realization of future SPS/MPT systems

Zero Poynting vector E∥H Beltrami field cylindrical cavity resonators

In this paper, we present novel cylindrical cavity resonators accommodating spatially and temporally zero Poynting vector Beltrami standing waves with the parallel electric and magnetic fields (E∥H). We introduce the special boundary conditions, i.e., longitudinal electromagnetic conductor (LEMC) on which zero longitudinal electromagnetic components are enforced and circumferential electromagnetic conductor (CEMC) on which zero circumference electromagnetic components are enforced in an axisymmetric waveguide system, and show that the zero Poynting vector E∥H Beltrami standing wave is generated as a superposition of dual degenerated axisymmetric TM and TE standing waves in a cylindrical resonator using the LEMC and CEMC boundary conditions. We present physical implementation methods of the LEMC and CEMC boundary conditions composed of the circumferentially arranged corrugations and the concentrically aligned cylindrical thin fins, respectively. In addition, we numerically demonstrate the Beltrami standing field generation and reveal its peculiar electromagnetic properties: the spatially and temporally E∥H with zero Poynting vector distribution, identical electric and magnetic energy density distributions, and zero local reactive energy flow

Strigolactone can promote or inhibit shoot branching by triggering rapid depletion of the auxin efflux protein PIN1 from the plasma membrane.

Plants continuously extend their root and shoot systems through the action of meristems at their growing tips. By regulating which meristems are active, plants adjust their body plans to suit local environmental conditions. The transport network of the phytohormone auxin has been proposed to mediate this systemic growth coordination, due to its self-organising, environmentally sensitive properties. In particular, a positive feedback mechanism termed auxin transport canalization, which establishes auxin flow from active shoot meristems (auxin sources) to the roots (auxin sinks), has been proposed to mediate competition between shoot meristems and to balance shoot and root growth. Here we provide strong support for this hypothesis by demonstrating that a second hormone, strigolactone, regulates growth redistribution in the shoot by rapidly modulating auxin transport. A computational model in which strigolactone action is represented as an increase in the rate of removal of the auxin export protein, PIN1, from the plasma membrane can reproduce both the auxin transport and shoot branching phenotypes observed in various mutant combinations and strigolactone treatments, including the counterintuitive ability of strigolactones either to promote or inhibit shoot branching, depending on the auxin transport status of the plant. Consistent with this predicted mode of action, strigolactone signalling was found to trigger PIN1 depletion from the plasma membrane of xylem parenchyma cells in the stem. This effect could be detected within 10 minutes of strigolactone treatment and was independent of protein synthesis but dependent on clathrin-mediated membrane trafficking. Together these results support the hypothesis that growth across the plant shoot system is balanced by competition between shoot apices for a common auxin transport path to the root and that strigolactones regulate shoot branching by modulating this competition

Auto-Tracking Wireless Power Transfer System With Focused-Beam Phased Array

This article used image recognition and beam forming technology to build a phased array with target tracking and transmitting the microwaves with a focused beam. The coordinate position of the target is obtained from the image recognition module and converted into phase information for the phased array. This system was constructed by a 1 × 4 5.764-GHz phased array with four 4-bit phase shifters. The phase shifters created a focused beam, which requires not only the target’s direction angle but also the transmission distance. The target position as well as direction and distance information were gathered using image recognition. The tracking beam method was evaluated by simulation and actual measurement. The results showed that the focused beam can always be formed in real time to track the target. The transfer efficiency of the focused beam was improved higher than that of uniform phase beam within a distance of 50 cm. The automatic tracking power transmission system has a response time of about 100 ms

Quarter-wavelength E‖H Beltrami cavity resonators

In this paper, we present the design and implementation methods of quarter-wavelength resonators accommodating Beltrami standing waves with parallel electric and magnetic (E‖H) fields. The resonator is bounded by the quarter-wavelength longitudinal electromagnetic conductor (LEMC), the circumferential electromagnetic conductor (CMEC), and the radial electromagnetic conductor (REMC). The LEMC, CEMC, and REMC boundaries are artificially implemented by the circumferentially aligned corrugation, concentrically aligned circular fins, and axisymmetrically aligned radial fins, respectively. The coupling control methods by introducing slots in the CEMC and REMC with the external TM01 and TE01 circular waveguides are presented. We design the quarter-wavelength resonators with the implemented LEMC, CEMC, and REMC boundaries with controlled external couplings and numerically demonstrate their E‖H properties, which confirms the validity of the proposed design method

High-Power Simultaneous Wireless Information and Power Transfer System Based on an Injection-Locked Magnetron Phased Array

We built a phased array system for high-power simultaneous wireless information and power transfer (SWIPT) using four 5.8-GHz injection-locked magnetrons. In the magnetron injection-locked state, the transmission efficiency was measured at different modulation rates. The fluctuation in the transmission efficiency was not more than 0.5%. We observed that dynamic beamforming does not affect communication quality. Using the magnetron phased array system, SWIPT experiments revealed that a frequency modulated (FM) signal that carries a video camera signal is transmitted and decoded during dynamic beamforming. In this SWIPT system, the main lobe transfers power, and information can be demodulated in front of the magnetron phased array from −90° to 90°. The maximum transmitted microwave power of the proposed system is 1637 W

Abruptly Autofocusing Beams Based on Phase Modulated Zone Plate

2022 Asia-Pacific Microwave Conference (APMC), 29 November 2022 - 02 December 2022, Yokohama, JapanIn this paper, we introduce a phase modulated zone plate to generate the circular symmetric Airy beam (CSAB) with abruptly autofocusing characteristic at 30GHz. This phase modulated zone plate is a phase combination form of a radial phase plate and a lens, which would make the conventional generation system of CSAB more compact. Based on full wave simulation, the unique abruptly autofocusing is explored in the field of millimeter wave. Even if the metal plate is placed in front of the phase modulated zone plate, the focusing can still be well obtained, which provides a potential advantage in millimeter-wave sensing

Aperture-Coupled Beam-Scanning Patch Array With Parasitic Elements Using a Reconfigurable Series-Fed Phase-Shifting Structure

In this letter, we propose a reconfigurable series-fed phase-shifting structure with movable metal plate for active millimeter wave beam-scanning application. The proposed phase-shifting structure can be equivalent to a certain number of phase shifters in the series-fed network. It can be easily controlled with only one metal plate, which further simplify the design of control system for phase shifters and reduce the cost. A prototype of 1-D aperture-coupled patch array with parasitic elements at 28GHz is designed, fabricated and measured for verifying the performance of the proposed phase-shifting structure. The measurement results at 28 GHz show 1-D beam-steering capability with maximum steering angle of ∼22 deg at H-plane can be achieved, revealing great potentials for developing the simple control and cost-effective active phased array for millimeter wave wireless power transmission application

Regulation of male germline transmission patterns by the Trp53-Cdkn1a pathway

A small number of offspring are born from the numerous sperm generated from spermatogonial stem cells (SSCs). However, little is known regarding the rules and molecular mechanisms that govern germline transmission patterns. Here we report that the Trp53 tumor suppressor gene limits germline genetic diversity via Cdkn1a. Trp53-deficient SSCs outcompeted wild-type (WT) SSCs and produced significantly more progeny after co-transplantation into infertile mice. Lentivirus-mediated transgenerational lineage analysis showed that offspring bearing the same virus integration were repeatedly born in a non-random pattern from WT SSCs. However, SSCs lacking Trp53 or Cdkn1a sired transgenic offspring in random patterns with increased genetic diversity. Apoptosis of KIT⁺ differentiating germ cells was reduced in Trp53- or Cdkn1a-deficient mice. Reduced CDKN1A expression in Trp53-deficient spermatogonia suggested that Cdkn1a limits genetic diversity by supporting apoptosis of syncytial spermatogonial clones. Therefore, the TRP53-CDKN1A pathway regulates tumorigenesis and the germline transmission pattern