scholarly journals Near-Field-Based 5G Sub-6 GHz Array Antenna Diagnosis Using Transfer Learning

2021 ◽  
Vol 11 (21) ◽  
pp. 10164
Author(s):  
Hong Jun Lim ◽  
Dong Hwan Lee ◽  
Hark Byeong Park ◽  
Keum Cheol Hwang
Keyword(s):  
Transfer Learning ◽  
Near Field ◽  
Array Antenna ◽  
Excitation Signal ◽  
Measurement Results ◽  
Field Lines ◽  
Abnormal Operation ◽  
Trained Network

In this paper, we propose a method for near-field-based 5G sub 6-GHz array antenna diagnosis using transfer learning. A classification network was implemented for normal/abnormal operation of the array antenna and the failure of a specific port. Furthermore, a regression network that could predict the amplitude and phase of the excitation signal of the array antenna was employed. Additionally, to accelerate the array antenna diagnosis, several near-field lines were sampled and reflected in the regression network. The proposed method was verified by measuring a fabricated 5G sub-6 GHz band 4×4 array antenna in various scenarios using a divider and coaxial cables. The tests showed that the trained network accurately diagnosed 29 of 30 measurement results.

scholarly journals Phase-to-pattern inverse design paradigm for fast realization of functional metasurfaces via transfer learning

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ruichao Zhu ◽  
Tianshuo Qiu ◽  
Jiafu Wang ◽  
Sai Sui ◽  
Chenglong Hao ◽  
...  
Keyword(s):  
Transfer Learning ◽  
Electromagnetic Waves ◽  
Inverse Method ◽  
Inverse Design ◽  
Learning Network ◽  
Design Paradigm ◽  
Simulation And Experiment ◽  
Meta Atom ◽  
Trained Network ◽  
Input Phase

AbstractMetasurfaces have provided unprecedented freedom for manipulating electromagnetic waves. In metasurface design, massive meta-atoms have to be optimized to produce the desired phase profiles, which is time-consuming and sometimes prohibitive. In this paper, we propose a fast accurate inverse method of designing functional metasurfaces based on transfer learning, which can generate metasurface patterns monolithically from input phase profiles for specific functions. A transfer learning network based on GoogLeNet-Inception-V3 can predict the phases of 28×8 meta-atoms with an accuracy of around 90%. This method is validated via functional metasurface design using the trained network. Metasurface patterns are generated monolithically for achieving two typical functionals, 2D focusing and abnormal reflection. Both simulation and experiment verify the high design accuracy. This method provides an inverse design paradigm for fast functional metasurface design, and can be readily used to establish a meta-atom library with full phase span.

scholarly journals Multi-Probe Measurement System Based on Single-Cut Transformation for Fast Testing of Linear Arrays

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1744
Author(s):  
Fernando Rodríguez Varela ◽  
Manuel José López Morales ◽  
Rubén Tena Sánchez ◽  
Alfonso Tomás Muriel Barrado ◽  
Elena de la Fuente González ◽  
...  
Keyword(s):  
Measurement System ◽  
Near Field ◽  
Linear Measurement ◽  
Complete Characterization ◽  
Linear Arrays ◽  
Full Characterization ◽  
X Band ◽  
Measurement Results ◽  
The Many ◽  
3D Information

This paper introduces a near-field measurement system concept for the fast testing of linear arrays suited for mass production scenarios where a high number of nominally identical antennas needs to be measured. The proposed system can compute the radiation pattern, directivity and gain on the array plane, as well as the array complex feeding coefficients in a matter of seconds. The concept is based on a multi-probe antenna array arranged in a line which measures the near field of the antenna under test in its array plane. This linear measurement is postprocessed with state-of-the-art single-cut transformation techniques. To compensate the lack of full 3D information, a previous complete characterization of a “Gold Antenna” is performed. This antenna is nominally identical to the many ones that will be measured with the proposed system. Therefore, the data extracted from this full characterization can be used to complement the postprocessing steps of the single-cut measurements. An X-band 16-probe demonstrator of the proposed system is implemented and introduced in this paper, explaining all the details of its architecture and operation steps. Finally, some measurement results are given to compare the developed demonstrator with traditional anechoic measurements, and show the potential capabilities of the proposed concept to perform fast and reliable measurements.

scholarly journals Near-Field Antenna Measurements with Manual Collection of the Measurement Samples

2020 ◽  
Vol 18 ◽  
pp. 17-22
Author(s):  
Fabian T. Faul ◽  
Hans-Jürgen Steiner ◽  
Thomas F. Eibert
Keyword(s):  
Near Field ◽  
Field Measurements ◽  
Controlled Environment ◽  
Positioning System ◽  
Probe Position ◽  
Site Testing ◽  
Error Level ◽  
Measurement Results ◽  
Anechoic Chambers ◽  
Chamber Measurements

Abstract. Near-field measurements are commonly performed in anechoic chambers which limits the flexibility of the measurements and requires high precision equipment to achieve exact results. In this contribution, we investigate a simple near-field measurement setup which does not use any sophisticated positioning system nor operates in a controlled environment. Instead, the probe antenna is moved by an operator person while the probe position is measured by a laser tracker. This implies that the measurement results will have a higher error level in comparison with antenna chamber measurements. However, excellent error levels are not always necessary, especially when it comes to on-site testing of the principle functionality of antennas. Measurement results are shown to illustrate the performance of the system.

Evaluation of Specific Absorption Rate due to Medical Implant in Near-Field Exposure

2013 ◽  
Vol 64 (3) ◽  
Author(s):  
Nazirah Othman ◽  
Noor Asmawati Samsuri ◽  
Norfatin Akma Ellias
Keyword(s):  
Intramedullary Nail ◽  
Specific Absorption Rate ◽  
Near Field ◽  
Dipole Antenna ◽  
Medical Implants ◽  
Field Exposure ◽  
Maximum Enhancement ◽  
Medical Implant ◽  
Measurement Results ◽  
Simulation Results

This paper presents the effects of conductive medical implant on energy absorbed by the human body and the testicular area when exposed to near field electromagnetic radiation. A dipole antenna is used as the radiating source and it is placed in front of the trousers pocket. Two types of medical implants are used in this study: intramedullary nail and bone plate. Numerical simulations are performed by means of CST Microwave Studio. Results are discussed in terms of changes in SAR values due to the presence of conductive medical implant at 0.4, 0.9, 1.8 and 2.4 GHz. The results have indicated that the conductive intramedullary nail that is located inside the femur significantly increases the SAR. Maximum enhancement in SAR is found when the length of the intramedullary nail is approximately one wavelength of the respective frequency tested. The measurement results indicate good agreements with the simulation results at 2.4 GHz.

scholarly journals Design and Optimization for 77 GHz Series-Fed Patch Array Antenna Based on Genetic Algorithm

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3066 ◽  
Author(s):  
Shuo Yang ◽  
Lijun Zhang ◽  
Jun Fu ◽  
Zhanqi Zheng ◽  
Xiaobin Zhang ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Array Antenna ◽  
Sidelobe Suppression ◽  
Automotive Radar ◽  
Sidelobe Level ◽  
Design And Optimization ◽  
Measurement Results ◽  
Antenna Length ◽  
Half Power ◽  
77 Ghz

This paper proposes a method for designing a 77 GHz series-fed patch array antenna. Based on the traditional genetic algorithm, the study explores different array topologies consisting of the same microstrip patches to optimize the design. The main optimization goal is to reduce the maximum sidelobe level (SLL). A 77 GHz series-fed patch array antenna for automotive radar was simulated, fabricated, and measured by employing this method. The antenna length was limited to no longer than 3 cm, and the array only had a single compact series with the radiation patch about 1.54 mm wide. In the genetic algorithm used for optimization, the maximum sidelobe level was set equal to or less than −14 dB. The measurement results show that the gain of the proposed antenna was about 15.6 dBi, E-plane half-power beamwidth was about ±3.8°, maximum sidelobe level was about −14.8 dB, and H-plane half-power beamwidth was about ±30° at 77 GHz. The electromagnetic simulation and the measurement results show that the 77 GHz antenna designed with the proposed method has a better sidelobe suppression by over 4 dB than the traditional one of the same length in this paper.

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