scholarly journals Beam focusing antenna array technology for non-stationary mobility

2016 ◽  
Author(s):  
Hind Zaaraoui ◽  
Zwi Altman ◽  
Eitan Altman
Keyword(s):  
Antenna Array ◽  
Beam Focusing ◽  
Array Technology

scholarly journals A Review of Antenna Array Technologies for Point-to-Point and Point-to-Multipoint Wireless Communications at Millimeter-Wave Frequencies

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
G. Federico ◽  
D. Caratelli ◽  
G. Theis ◽  
A. B. Smolders
Keyword(s):  
Wireless Communications ◽  
Antenna Array ◽  
Antenna Arrays ◽  
Communication Systems ◽  
High Gain ◽  
Multimedia Services ◽  
Ongoing Research ◽  
Array Technology ◽  
Point To Point ◽  
Technical Solutions

With the introduction of 5G communication systems operating in the mm-wave frequency range, new opportunities in terms of multimedia services and applications will become available. For this to happen, several technical challenges from an antenna standpoint need to be addressed. The achievements of high-gain characteristics and agile beamforming with wide-scan capabilities are the main targets of the ongoing research on mm-wave antenna arrays. In this paper, an up-to-date overview of antenna array technology for wireless communications at mm-wave frequencies is given. Particular focus is put on the review of the state-of-the art and most advanced antenna array concepts for point-to-point and point-to-multipoint radio links at said frequencies. Various figures of merit are assessed for a comprehensive analysis and bench marking of the technical solutions investigated in the presented survey.

scholarly journals Efficiency of the Miniature Anti-jam GNSS Antenna Array

2018 ◽  
pp. 37-46
Author(s):  
A. V. Nemov ◽  
D. A. Nemov ◽  
D. L. Minh ◽  
S. A. Saveliev ◽  
A. N. Plastikov
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
Interference Suppression ◽  
Point Of View ◽  
High Tech ◽  
Array Technology ◽  
Negative Effect ◽  
Miniaturized Antenna ◽  
Miniature Antennas ◽  
Miniature Antenna

The use of the miniature controlled reception pattern antennas (CRPAs) in GNSS equipment is one of the trends in GPS, Baidow, GLONASS development. A miniaturized GPS antenna array technology reduces the size of the antenna elements and the array dimensions. Miniature CRPAs are in demand not only with mass consumer of GPS/GLONASS house-hold equipment, but with expert users of complex hardware as well, where high-tech multi-sensor miniature antenna systems (AC) can be applied. Such types of AC used for intelligent control of spatial selectivity are considered as antenna arrays. The advantages of miniature CRPAs with anti-jamming capability include possibility to be installed on vehicles where it used to be impossible due to their size. The negative effect of miniaturization is in degradation of some antennas characteristics, such as gain, suppression of the reverse lobe of radiation pattern (RP), a heterogeneity of RP. In miniature antennas, the resonator interinfluence increases, that leads to distortion of individual emitters RP and to the in-crease of the total RP lobe of the antenna array irregularity, as well as the width of RP lobe. Designers take special measures to reduce the interinfluence of the resonators. However, they are not fully described in the available literature. Therefore, the achieved performance of miniature CRPAs is in great interest. The final criterion (from a consumer point of view) is in effective functional of a device containing a miniature CRPA, the degradation of its parameters in compare with traditional CRPA equipment of expert users. The authors focus on property investigation of miniature CRPAs manufactured primarily by US industry. Specifications of two antennas and some expected details of the miniaturized antenna array technology are described along with the test results of their ability to perform the objective function jammer suppression. The article contains the results obtained from independent testing of electrodynamics parameters of miniature L1/L2 frequency CRPA and its design analysis. The experimental data of sensor interinfluence are outlined. The measures to reduce the sensor interinfluence are take into account. The efficiency of the miniature antenna is estimated in the process of interference suppression by means of computer simulation. The Monte-Carlo method is applied. For the sake of generality, two types of algorithm for interference suppression are used.

Applying Virtual Antenna Array Technology to Minimize DOA Errors

2021 ◽  
Author(s):  
Evgeniy A. Ishchenko ◽  
Yuri G. Pasternak ◽  
Vladimir A. Pendyurin ◽  
Sergey M. Fedorov
Keyword(s):  
Antenna Array ◽  
Array Technology

Восстановление изображения отражателей на границе основного металла и сварного соединения с использованием ультразвуковых антенных решеток

2021 ◽  
pp. 3-17
Author(s):  
А.Е. Базулин ◽  
Е.Г. Базулин ◽  
А.Х. Вопилкин ◽  
Д.С. Тихонов
Keyword(s):  
Antenna Array ◽  
Welded Joints ◽  
Phased Array ◽  
Ultrasonic Inspection ◽  
Control Object ◽  
Fusion Boundary ◽  
High Quality ◽  
Array Technology

The article suggests an effective method of replacing zonal focusing with an antenna array, traditionally used for automated ultrasonic inspection of welded joints with a narrow cutting to detect defects at the fusion boundary. This method, based on the use of multi-circuit digital focusing antenna technology (DFA), allows you to obtain and analyze high-quality images of reflectors. The proposed method, in comparison with zonal focusing made using phased array technology, is less sensitive to the accuracy of positioning the antenna array relative to the seam axis and to changes in the thickness of the control object, allows you to estimate the height of defects not by the amplitude attribute, but by the size of the glare reflectors.

scholarly journals The Unbiased Characteristic of Doppler Frequency in GNSS Antenna Array Processing

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Yuchen Xie ◽  
Zhengrong Li ◽  
Feiqiang Chen ◽  
Huaming Chen ◽  
Feixue Wang
Keyword(s):  
Antenna Array ◽  
Carrier Phase ◽  
Array Processing ◽  
Doppler Frequency ◽  
Low Complexity ◽  
Satellite System ◽  
Accurate Estimation ◽  
Array Technology ◽  
Gnss Receivers ◽  
Global Navigation Satellite

The antenna array technology, especially the spaced-time array processing (STAP), is one of the effective methods used in Global Navigation Satellite System (GNSS) receivers to refrain the power of jamming and enhance the performance of receivers in the circumstance of interference. However, biases induced to the receiver because of many reasons, including characteristic of antennas, front-end channel electronics, and space-time filtering, are extremely harmful to the high precise positioning of receivers. Although plenty of works have been done to calibrate the antenna and to mitigate these biases, achieving a good performance of antijamming, high accuracy, and low complexity at the same time still remains challenging. Different from existing works, this paper leverages the characteristic of GNSS signal’s Doppler frequency in STAP, which is proven to remain unbiased to solve the problem, even when the nonideal antennas are used and the interference circumstance changes. Since the integration of frequency is carrier phase, the unbiased Doppler frequency leads to an accurate estimation of carrier phase which can be used to calibrate the antenna array without extra apparatus or complicating algorithms. Therefore, a simple Doppler-aid strategy may be developed in the future to solve the difficulty of STAP bias mitigation.

scholarly journals DYNAMIC FOCUSING OF ELECTROACOUSTIC ARRAYS IN NON‐DESRUCTIVE CONTROL COMPOSITE MATERIALS

Aviation ◽  
2010 ◽  
Vol 14 (2) ◽  
pp. 49-53
Author(s):  
Eugenijus Pileckas
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Antenna Array ◽  
Beam Focusing ◽  
Material Analysis ◽  
Modelling Method ◽  
Acoustic Images ◽  
Acoustic Antenna ◽  
Control Technologies ◽  
Non Destructive

Nowadays the application possibilities for composite materials for aviation are increasing, and monitoring their quality during production and exploitation is becoming more and more relevant. Acoustic non‐destructive control technologies provide promising possibilities for monitoring and analysing the characteristics and parameters of composites. This paper discusses an acceptable modelling method based on acoustic images of composite material analysis using a dynamic beam focusing method of an acoustic antenna array. Santrauka Vis plačiau naudojant kompozitines medžiagas aviacijoje aktualeja ir ju kokybes būsenos stebejimas konstrukciju gamybos ir eksploatacijos metu. Akustines neardomosios kontroles technologijos atveria, mūsu nuomone, perspektyvias kompozitiniu medžiagu charakteristiku bei ju parametru stebejimo ir tyrimo galimybes. Straipsnyje nagrinejamas priimtinas kompozitiniu medžiagu tyrimui akustiniu vaizdu formavimo būdas, panaudojant akustines antenu gardeles dinamini spindulio fokusavimo būda.

Point-Cathode Electron Gun Using Electron-Beam Bombardment for Cathode Tip Heating

1990 ◽  
Vol 48 (1) ◽  
pp. 198-199
Author(s):  
Ryo Iiyoshi ◽  
Susumu Maruse ◽  
Hideo Takematsu
Keyword(s):  
Electron Beam ◽  
Tungsten Wire ◽  
Local Heating ◽  
Electron Gun ◽  
Original Position ◽  
Beam Power ◽  
Radius Of Curvature ◽  
High Brightness ◽  
Beam Focusing ◽  
Time Operation

Point cathode electron gun with high brightness and long cathode life has been developed. In this gun, a straightened tungsten wire is used as the point cathode, and the tip is locally heated to higher temperatures by electron beam bombardment. The high brightness operation and some findings on the local heating are presented.Gun construction is shown in Fig.l. Small heater assembly (annular electron gun: 5 keV, 1 mA) is set inside the Wehnelt electrode. The heater provides a disk-shaped bombarding electron beam focusing onto the cathode tip. The cathode is the tungsten wire of 0.1 mm in diameter. The tip temperature is raised to the melting point (3,650 K) at the beam power of 5 W, without any serious problem of secondary electrons for the gun operation. Figure 2 shows the cathode after a long time operation at high temperatures, or high brightnesses. Evaporation occurs at the tip, and the tip part retains a conical shape. The cathode can be used for a long period of time. The tip apex keeps the radius of curvature of 0.4 μm at 3,000 K and 0.3 μm at 3,200 K. The gun provides the stable beam up to the brightness of 6.4×106 A/cm2sr (3,150 K) at the accelerating voltage of 50 kV. At 3.4×l06 A/cm2sr (3,040 K), the tip recedes at a slow rate (26 μm/h), so that the effect can be offset by adjusting the Wehnelt bias voltage. The tip temperature is decreased as the tip moves out from the original position, but it can be kept at constant by increasing the bombarding beam power. This way of operation is possible for 10 h. A stepwise movement of the cathode is enough for the subsequent operation. Higher brightness operations with the rapid receding rates of the tip may be improved by a continuous movement of the wire cathode during the operations. Figure 3 shows the relation between the beam brightness, the tip receding rate by evaporation (αis the half-angle of the tip cone), and the cathode life per unit length, as a function of the cathode temperature. The working life of the point cathode is greatly improved by the local heating.

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