Design of graded honeycomb radar absorbing structure with wide-band and wide-angle properties

2018 ◽  
Vol 11 (2) ◽  
pp. 143-150 ◽  
Author(s):  
Yuchen Zhao ◽  
Fang Ren ◽  
Li He ◽  
Jinsheng Zhang ◽  
Yanning Yuan ◽  
...  
Keyword(s):  
Transverse Electric ◽  
Incident Angle ◽  
Wide Band ◽  
Transverse Magnetic ◽  
Magnetic Polarization ◽  
Wide Range ◽  
Transverse Magnetic Polarization ◽  
Radar Absorbing Structure ◽  
Theoretical Limitation ◽  
Good Agreement

AbstractIn this paper, the design of a graded honeycomb radar absorbing structure (RAS) is presented to realize both a wide bandwidth and absorption over a wide range of angles. For both transverse-electric and transverse-magnetic polarization, a fractional bandwidth of more than 118.6% is achieved for at least a 10 dB reflectivity reduction when the incident angle is <45°, an 8 dB reduction when the incident angle is <55° and a 5 dB reduction when the incident angle is <70°. Meanwhile the 10 dB reduction upper angle limit is approximately 30° for the uniform coating honeycomb RAS in the literature, which loses its absorbing ability when the incident angle is larger than 55°. Furthermore, the total thickness of our design is 10.7 mm, which is only approximately 1.29 times that of the theoretical limitation. The good agreement between the calculated, simulated, and measured results demonstrates the validity of this optimization.

Lateral and transverse shifts in reflected dipole radiation

2011 ◽  
Vol 467 (2133) ◽  
pp. 2500-2519 ◽  
Author(s):  
M. V. Berry
Keyword(s):  
Electromagnetic Waves ◽  
Poynting Vector ◽  
Transverse Electric ◽  
Transverse Magnetic ◽  
Magnetic Polarization ◽  
Dipole Radiation ◽  
Plane Transverse ◽  
Out Of Plane ◽  
Transverse Magnetic Polarization ◽  
Large Peak

In-plane (lateral) and out-of-plane (transverse) shifts in the direction of arbitrarily polarized electromagnetic waves in a denser medium, reflected totally or partially at an interface with a rarer medium, are calculated exactly, in terms of the deviation of the Poynting vector from radial. The shifts are analogous to the Goos–Hänchen and Fedorov–Imbert shifts for beams. There is a transverse shift even for unreflected dipole radiation if the polarization is not linear. With reflection, there is a transverse shift for linear polarization, provided this is not pure transverse electric or transverse magnetic. The contributions from the geometrical ray, the lateral ray that interferes strongly with it, and the large peak at the Brewster angle (for transverse magnetic polarization), are calculated asymptotically far from the geometrical image. At the critical angle, the lowest order asymptotics is inadequate and a more sophisticated treatment is devised, reproducing the exact shifts accurately.

On the inversion and phase recovery of scattered electromagnetic amplitude data

1989 ◽  
Vol 426 (1871) ◽  
pp. 361-375 ◽  
Keyword(s):  
Electromagnetic Scattering ◽  
Transverse Electric ◽  
Complex Structure ◽  
Polarization State ◽  
Scattering Problem ◽  
Transverse Magnetic ◽  
One Dimensional ◽  
Amplitude Data ◽  
Transverse Magnetic Polarization ◽  
The One

The one-dimensional inverse electromagnetic scattering problem for the inversion of amplitude data of either linear polarization state is investigated. The method exploits the complex structure of the field scattered from a class of inhomogeneous dielectrics and enables the analytic signal to be reconstructed from measurements of the amplitude alone. The method is demonstrated and exemplified with experimental data in both transverse electric and transverse magnetic polarization states. The implications of the method as a means for regularization of scattered data are briefly discussed.

scholarly journals Machine–learning-enabled metasurface for direction of arrival estimation

Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Min Huang ◽  
Bin Zheng ◽  
Tong Cai ◽  
Xiaofeng Li ◽  
Jian Liu ◽  
...  
Keyword(s):  
Machine Learning ◽  
Incident Angle ◽  
Wide Band ◽  
Direction Of Arrival ◽  
Doa Estimation ◽  
Signal Acquisition ◽  
Reconstruction Algorithms ◽  
Time Saving ◽  
Wide Range

Abstract Metasurfaces, interacted with artificial intelligence, have now been motivating many contemporary research studies to revisit established fields, e.g., direction of arrival (DOA) estimation. Conventional DOA estimation techniques typically necessitate bulky-sized beam-scanning equipment for signal acquisition or complicated reconstruction algorithms for data postprocessing, making them ineffective for in-situ detection. In this article, we propose a machine-learning-enabled metasurface for DOA estimation. For certain incident signals, a tunable metasurface is controlled in sequence, generating a series of field intensities at the single receiving probe. The perceived data are subsequently processed by a pretrained random forest model to access the incident angle. As an illustrative example, we experimentally demonstrate a high-accuracy intelligent DOA estimation approach for a wide range of incident angles and achieve more than 95% accuracy with an error of less than 0.5 ° $0.5{\degree}$ . The reported strategy opens a feasible route for intelligent DOA detection in full space and wide band. Moreover, it will provide breakthrough inspiration for traditional applications incorporating time-saving and equipment-simplified majorization.

scholarly journals Bidirectional Angle-Tolerant Polarization-Tuned Filtering and Wide-Range Refractive Index Sensing Based on Metal Film Coated Nanograting

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 47
Author(s):  
Wenli Cui ◽  
Qiannan Wu ◽  
Bo Chen ◽  
Xufeng Li ◽  
Xiaolin Luo ◽  
...  
Keyword(s):  
Refractive Index ◽  
Metal Film ◽  
High Performance ◽  
Incident Angle ◽  
Single Layer ◽  
Transverse Magnetic ◽  
Photonic Devices ◽  
Biomedical Sensors ◽  
Dual Channel ◽  
Wide Range

The miniaturization and integration of photonic devices are new requirements in the fast-growing optics field. In this paper, we focus on a feature-rich sub-wavelength nanograting-coated single-layer metal film. The numerical results show that the reflection behaviors of this proposed structure can realize bidirectional dual-channel ultra-narrowband polarized filtering and bidirectional wavelength-modulated sensing in a wide refractive index (RI) range from 1.0 to 1.4 for incident angle of 10° with transverse-magnetic (TM) polarized illumination at wavelengths between 550 nm to 1500 nm. Moreover, the bidirectional properties of filtering and sensing are not obviously decreased when increasing incident angle from 10° to 30°, and decreasing incident angle from 10° to 0°. The calculated RI sensitivity can be up to 592 nm/RIU with a high figure of merit (FOM) of 179.4 RIU−1. More to the point, this nanograting has a simple structure and is less sensitive to the height and shape of grating ridge, which provides great convenience for the fabrication of devices. The other thing that is going on is that this structure can also realize synchronously tunable color filtering, including green to red, with high color purity in the visible band by choosing the period. The underlying physical mechanism is analyzed in detail, and is primarily attributed to surface plasmon polariton (SPP) resonance and dipole resonance at double plasmon resonance wavelengths. This work has tremendous potential in developing multipurpose and high-performance integrated optical devices such as spectral filters, colored displays and plasmon biomedical sensors.

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