Broadband, Beam-Steering Asymmetric Stacked Microstrip Phased Array with Enhanced Front-to-Back Ratio

2021 ◽  
Vol 36 (3) ◽  
pp. 273-281
Author(s):  
Melih Turk ◽  
Fikret Tokan
Keyword(s):  
Phased Array ◽  
Phased Arrays ◽  
Linear Array ◽  
Beam Steering ◽  
Impedance Matching ◽  
Base Station ◽  
Critical Problem ◽  
Backward Radiation ◽  
Broadside Radiation ◽  
Asymmetric Configuration

The backward radiation is a critical problem that may cause breakdown of the front-end circuits that are integrated behind the antenna. Thus, antennas having high Front to Back Ratio (FBR) are required. For phased arrays, the back lobe suppression is required for all scanning angles at all frequencies of the band. In this work, a stacked patch linear array with asymmetric configuration is proposed. It is capable of scanning the beam in ±40° with less than 1.34 dB scanning loss. Due to the usage of probe-fed stacked patches as the antenna elements, impedance matching in 8-10 GHz is achieved. More than 30 dB FBR is obtained for broadside radiation. It is above 20 dB when the beam is steered to θ = 40°. This is valid for all frequencies of the band. A prototype is fabricated and measured. Higher than 38 dB FBR is observed. With its broadband, high FBR and low scanning loss, the proposed asymmetrical stacked patch phased array is suitable as radar and base station antenna.

Pressure Vessels Inspections Using Ultrasonic Phased Arrays

2003 ◽  
Author(s):  
Michael D. C. Moles ◽  
Fre´de´ric Jacques ◽  
Noe¨l Dube´
Keyword(s):  
Defect Detection ◽  
Phased Array ◽  
Phased Arrays ◽  
Beam Steering ◽  
Pressure Vessels ◽  
Probability Of Detection ◽  
Inspection Time ◽  
Narrow Gap ◽  
Beam Shape ◽  
Lack Of Fusion

Phased arrays offer significant technical advantages for weld inspections over conventional ultrasonics. The phased array beams can be steered, scanned, swept and focused electronically. Beam steering permits the selected beam angles to be optimized ultrasonically by orienting them perpendicular to the predicted defects, especially Lack of Fusion. Electronic (linear) scanning permits very rapid coverage of the welds. Beam steering (usually called sectorial or azimuthal scanning) can be used for mapping welds at appropriate angles to optimize Probability of Detection of defects. Electronic focusing permits optimizing the beam shape and size at the expected defect location, also to optimize Probability of Detection. Overall, the use of phased arrays permits optimizing defect detection while minimizing inspection time. The paper describes the application of phased arrays for inspecting pressure vessel welds. Phased arrays offer significant practical advantages over conventional automated inspections. Thick section weld inspections typically use the established “top, side, end” or “top, side, TOFD” views of the weld. Other displays can be used, e.g. strip charts for zone discrimination scanning of narrow gap welds. Special inspections can be easily performed with phased arrays, e.g. additional beams for extra coverage, multiple angles or inspection set-ups simultaneously, or special scans such as tandem probes. Different delivery systems and instrumentation can be assembled for any required scan. Fitness-For-Service inspections requiring high PoD and accurate sizing can be performed using upscale systems. These phased array inspections can be tailored to any known code requirements.

Implement of Lamb Wave Using PZT Phased Arrays for Structural Health Monitoring

2013 ◽  
Vol 347-350 ◽  
pp. 36-39 ◽  
Author(s):  
Ya Jie Sun ◽  
Yong Hong Zhang ◽  
Cheng Shan Qian
Keyword(s):  
Time Delay ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Lamb Wave ◽  
Phased Array ◽  
Phased Arrays ◽  
Wave Beam ◽  
Beam Steering ◽  
Damage Localization ◽  
Localization Method

Phased array theory is analyzed. The PZT phased array is applied in SHM for the Al plate to identify the hole in the structure. The Lamb wave beam steering is controlled by adding the time delay to the signals. The structure can be scanned in half plane by using the phased array theory to control the Lamb wave beam steering. The damage in the structure can be recognized and localized by the phased array method. The identification result is shown on mapped image. The phased array damage localization method is verified by the experiment and the result shows that the method is effective to recognize the hole damage in the structure.

The Design of an Ultrasonic Phased Array System on Pipelines’ Weld Inspection

2004 ◽  
Author(s):  
Shili Chen ◽  
Guangde Song ◽  
Shijiu Jin ◽  
Xianglin Zhan
Keyword(s):  
Time Delays ◽  
Phased Array ◽  
Phased Arrays ◽  
Beam Steering ◽  
Specific Model ◽  
Ultrasonic Signal ◽  
Ultrasonic Waves ◽  
Inspection System ◽  
Destructive Interference ◽  
Weld Inspection

Phased arrays generate ultrasonic waves by using recisely-defined time delays for each element in an ultrasonic array group, this permits constructive and destructive interference of the wavefronts to form the pre-defined beam. So, ultrasonic phased arrays are well suited to weld inspections. First, beams can be multiplexed across the array, in what is called “electronic scanning”. This permits very rapid inspections of components, typically an order of magnitude faster than a single transducer raster scan. Second, the beam can be swept through a range of angles without moving the array; this is called “beam steering”, and the inspections are typically called “azimuthal” scans or “sectorial” scans. Before weld inspecting, the time delays between elements were computed using a specific model and compared to experimental delays obtained using through transmission tests. This paper describes the application of phased array on pipelines’ weld inspection. The detail hardware designs of linear phased arrays system and the summary of system performance are presented. This inspection system includes eight ultrasonic signal transmitting and receiving circuit units, which are used to control time sequence of ultrasonic beam and select channel used for waves construction, and amplify the received ultrasonic signal. Each unit is connected with 16 probe elements (total 128 elements in this system), and can receive 4-way ultrasonic signals (channel selection is done by RF switching). Additional performance is gained by intensively using FPGA (Field Programmable Gate Arrays) technology for memory and delay counters. Since the working frequency or FPGA is 100MHz, the delay time less than 10 ns is realized by analogue delay line. This system not only has the functions of conventional ultrasonic inspector, but also can display the defect shape and its size on the screen.

An Optimized Scheme for Optical Phased Array Beam Steering Controlled by Wavelength

PIERS Online ◽  
2007 ◽  
Vol 3 (2) ◽  
pp. 127-131 ◽  
Author(s):  
Ying Zhao ◽  
Xiaozhou Yang ◽  
Qin Cai ◽  
Weiwei Hu
Keyword(s):  
Phased Array ◽  
Beam Steering ◽  
Optical Phased Array

scholarly journals A Design Approach of Optical Phased Array with Low Side Lobe Level and Wide Angle Steering Range

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 63
Author(s):  
Xinyu He ◽  
Tao Dong ◽  
Jingwen He ◽  
Yue Xu
Keyword(s):  
Phased Array ◽  
Phase Distribution ◽  
Beam Steering ◽  
Side Lobe ◽  
Design Approach ◽  
Optical Antennas ◽  
Side Lobe Level ◽  
Wide Angle ◽  
Spacing Distribution ◽  
Optical Phased Array

In this paper, a new design approach of optical phased array (OPA) with low side lobe level (SLL) and wide angle steering range is proposed. This approach consists of two steps. Firstly, a nonuniform antenna array is designed by optimizing the antenna spacing distribution with particle swarm optimization (PSO). Secondly, on the basis of the optimized antenna spacing distribution, PSO is further used to optimize the phase distribution of the optical antennas when the beam steers for realizing lower SLL. Based on the approach we mentioned, we design a nonuniform OPA which has 1024 optical antennas to achieve the steering range of ±60°. When the beam steering angle is 0°, 20°, 30°, 45° and 60°, the SLL obtained by optimizing phase distribution is −21.35, −18.79, −17.91, −18.46 and −18.51 dB, respectively. This kind of OPA with low SLL and wide angle steering range has broad application prospects in laser communication and lidar system.

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