scholarly journals Practical Aspects of Acoustic Leaky-Wave Antennas Applied to Underwater Direction Finding

2020 ◽  
Vol 2 (1) ◽  
pp. 93
Author(s):  
Ivan Felis-Enguix ◽  
Jorge Otero-Vega ◽  
María Campo-Valera ◽  
I. Villó-Pérez ◽  
J. L. Gómez-Tornero
Keyword(s):  
Low Cost ◽  
Beam Steering ◽  
Near Field ◽  
Doa Estimation ◽  
Direction Finding ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Sound Waves ◽  
Leaky Wave ◽  
First Time

Acoustic leaky-wave antennas (ALWAs) have demonstrated the capacity to steer directive sound waves in frequency-dependent directions, due to the inherent dispersive radiation characteristic of leaky modes. Compared to more conventional uniform linear array (ULA) acoustic traducers for electronic beam steering (which rely on multiple sensors), the ALWA allows for single microphone operation. Thus, ALWAs offer a direct mechanism to scan a directive acoustic beam in the angular space by simply sweeping the operating frequency of the acoustic signal, which envisions cost-efficient single-transducer direction finders for SONAR applications. In this paper, we study for the first time some important features of an ALWA for acoustic underwater Direction-of-Arrival (DoA) estimation applications. First, we report for the first time on the necessity to shape the radiated ALWA beams in both far- and near-field zones to improve the DoA estimation performance, following similar techniques recently applied for low-cost frequency-scanned direction-finding radars based on LWAs. Furthermore, the capacity to reduce the Side Lobe Level (SLL) has been analyzed in order to improve performance, demonstrating aperture tapering techniques to the ALWA for the first time. These acoustic behaviour aspects have a considerable interest in real applications of ALWA in innovative SONAR systems for underwater scenarios.

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.

scholarly journals Ka-Band Lightweight High-Efficiency Wideband 3D Printed Reflector Antenna

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Yu Zhai ◽  
Ding Xu ◽  
Yan Zhang
Keyword(s):  
High Efficiency ◽  
Near Field ◽  
Side Lobe ◽  
High Gain ◽  
Reflector Antenna ◽  
Field Analysis ◽  
Side Lobe Level ◽  
Ka Band ◽  
3D Printed ◽  
Reflecting Surface

This paper presents a lightweight, cost-efficient, wideband, and high-gain 3D printed parabolic reflector antenna in the Ka-band. A 10 λ reflector is printed with polylactic acid- (PLA-) based material that is a biodegradable type of plastic, preferred in 3D printing. The reflecting surface is made up of multiple stacked layers of copper tape, thick enough to function as a reflecting surface (which is found 4 mm). A conical horn is used for the incident field. A center-fed method has been used to converge the energy in the broadside direction. The proposed antenna results measured a gain of 27.8 dBi, a side lobe level (SLL) of −22 dB, and a maximum of 61.2% aperture efficiency (at 30 GHz). A near-field analysis in terms of amplitude and phase has also been presented which authenticates the accurate spherical to planar wavefront transformation in the scattered field.

Highly Directive Hybrid Plasmonic Leaky-Wave Optical Antenna With Controlled Side-Lobe Level

2015 ◽  
Vol 33 (23) ◽  
pp. 4791-4798 ◽  
Author(s):  
Mohammad Ali Panahi ◽  
Leila Yousefi ◽  
Mahmoud Shahabadi
Keyword(s):  
Side Lobe ◽  
Side Lobe Level ◽  
Optical Antenna ◽  
Leaky Wave

scholarly journals Analysis and Design of Leaky-Wave Antenna with Low SLL Based on Half-Mode SIW Structure

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Jiaying Guo ◽  
Zheng Li ◽  
Junhong Wang ◽  
Meie Chen ◽  
Zhan Zhang
Keyword(s):  
Structural Parameters ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Leaky Wave ◽  
Antenna Aperture ◽  
Antenna Structure ◽  
Analysis And Design ◽  
Leaky Wave Antenna ◽  
Radiated Power ◽  
Wave Antenna

This paper presents a novel leaky-wave antenna based on the Half-Mode Substrate Integrated Waveguide (HMSIW) structure with low side lobe level. The effect of the structural parameters of the LWAs on the radiation performances is studied. Using beam-forming technique, the leakage loss factorαalong the radiation aperture is designed in a tapered way by controlling the aperture depth along the structure. This controls the radiated power along the antenna aperture and finally achieves the radiation pattern with low SLL. Furthermore, the antenna structure is optimized to get an even lower SLL.

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