Microstrip Leaky-Wave Antenna for Radar Applications

The work in this article focuses on developing and improving the performance of new leaky-wave antenna configurations that can be adapted for use in radar systems. The study focused on the W-band, where we demonstrated the possibility of modifying resonant frequencies and reducing the number of patches required. The antenna was designed using HFSS, based on the finite element method. It we designed enabled us to observe the influence of the number of patches on the radiation pattern, and also to achieve low levels of minor’s lobes. and good directivity at the operating frequency. These patches are arranged in the shape of an inverted T. The interest of this study is to meet the requirements of radar antennas dedicated to detection.

Prediction of Bandwidth of Metamaterial Antenna Using Pearson Kernel-Based Techniques

The use of metamaterial enhances the performance of a specific class of antennas known as metamaterial antennas.The radiation cost and quality factor of the antenna are influenced by the size of the antenna.Metamaterial antennas allow for the circumvention of the bandwidth restriction for small antennas.Antenna parameters have recently been predicted using machine learning algorithms in existing literature.Machine learning can take the place of the manual process of experimenting to find the ideal simulated antenna parameters.The accuracy of the prediction will be primarily dependent on the model that is used.In this paper,a novel method for forecasting the bandwidth of the metamaterial antenna is proposed,based on using the Pearson Kernel as a standard kernel.Along with these new approaches,this paper suggests a unique hypersphere-based normalization to normalize the values of the dataset attributes and a dimensionality reduction method based on the Pearson kernel to reduce the dimension.A novel algorithm for optimizing the parameters of Convolutional Neural Network(CNN)based on improved Bat Algorithm-based Optimization with Pearson Mutation(BAO-PM)is also presented in this work.The prediction results of the proposed work are better when compared to the existing models in the literature.

Metamaterials and metasurfaces for designing metadevices:Perfect absorbers and microstrip patch antennas

In the past twenty years, electromagnetic metamaterials represented by left-handed metamaterials（LHMs） have attracted considerable attention due to the unique properties such as negative refraction, perfect lens, and electromagnetic cloaks. In this paper, we present a comprehensive review of our group＇s work on metamaterials and metasurfaces. We present several types of LHMs and chiral metamaterials. As a two-dimensional equivalent of bulk three-dimensional metamaterials, metasurfaces have led to a myriad of devices due to the advantages of lower profile, lower losses, and simpler to fabricate than bulk three-dimensional metamaterials. We demonstrate the novel microwave metadevices based on metamaterials and metasurfaces： perfect absorbers and microwave patch antennas, including novel transmission line antennas,high gain resonant cavity antennas, wide scanning phased array antennas, and circularly polarized antennas.

Metamaterial beam scanning leaky-wave antenna based on quarter mode substrate integrated waveguide structure

In this paper, we first propose a metamaterial structure by etching the same two interdigital fingers on the upper ground of quarter mode substrate integrated waveguide（QMSIW）. The simulated results show that the proposed QMSIWbased metamaterial has a continuous phase constant changing from negative to positive values within its passband. A periodic leaky-wave antenna（LWA）, which consists of 11 QMSIW-based metamaterial unit cells, is designed, fabricated,and measured. The measured results show that the fabricated antenna achieves a continuous beam scanning property from backward-43° to forward ＋32° over an operating frequencyrange of 8.9 GHz–11.8 GHz with return loss better than 10 d B.The measured antenna gain keeps consistent with the variation of less than 2 d B over the operating frequency range with a maximum gain of 12 d B. Besides, the measured and simulated results are in good agreement with each other, indicating the significance and effectiveness of this method.

Leaky-Wave Antennas for 5G/B5G Mobile Communication Systems:A Survey

Since leaky-wave antennas(LWAs)have the advantages of high directivity,low loss and structural simplicity,LWAs are very suitable for designing millimeter-wave(mmW)antennas.The purpose of this paper is to review the latest research progress of LWAs for 5G/B5G mobile communication systems.Firstly,the conventional classification and design methods of LWAs are introduced and the effects of the phase constant and attenuation constant on the radiation characteristics are discussed.Then two types of new LWAs for 5G/B5G mobile communication systems including broadband fixed-beam LWAs and frequencyfixed beam-scanning LWAs are summarized.Finally,the challenges and future research directions of LWAs for 5G/B5G mobile communication systems are presented.

Decoupling technique of patch antenna arrays with shared substrate by suppressing near-field magnetic coupling using magnetic metamaterials

In this paper,we propose the decoupling technique of patch antenna array by suppressing near-field magnetic coupling（NFMC） using magnetic metamaterials.To this end,a highly-integrated magnetic metamaterials,the substrate-integrated split-ring resonator（SI-SRR）,is firstly proposed to achieve negative permeability at the antenna operating frequency.By integrating SI-SRR in between two closely spaced antennas,magnetic fields are blocked in the shared substrate due to negative permeability of SI-SRR,reducing NFMC between the two antennas.To verify the technique,a prototype was fabricated and measured.The measured results demonstrated that the isolation can be enhanced by more than 17 dB even when the gap between the two patch antennas is only about 0.067 A.Due to high integration,this technique provides an effective alternative to high-isolation antenna array.

Design of continuous long slot leaky-wave antenna for millimeter wave application

A simple and efficient design scheme of the continuous long slot leaky-wave antenna is developed. The key steps involved in the scheme are summarized. First, the cut-off frequencies of slot waveguides with different slot offsets are obtained by 3D finite-difference time-domain （FDTD） method, Second, the attenuation function a^a is estimated by the aperture distribution, and the attenuation function αrs is determined by the slot radiation. Finally, the attenuation function αrs is combined with the attenuation function αrs by the coefficient K. And an example in Ka band is presented. Moreover, the return loss of the E-plane Tee-junction （ET） and the radiation pattern of leaky-wave antenna are simulated. The scheme is verified by comparing with the experimental result.

Spoof surface plasmon polaritons excited leaky-wave antenna with continuous scanning range from endfire to forward

A novel leaky-wave antenna(LWA)utilizing spoof surface plasmon polaritons(SSPPs)excitation is proposed with continuous scanning range from endfire to forward.The designed transmission line unit supports two SSPPS modes,of which the 2nd order mode is applied in the design.A novel strategy has been devised to excite the spatial radiation of the-1st order harmonics by arranging periodic counter changed sinusoidal structures on both sides of the SSPPs transmission line.Both full-wave simulation and measurement results show that the proposed LWA presents wide scanning angle from endfire to forward.In the frequency range from 4 GHz to 10 GHz,LWAs achieve scanning from 90°to+20°,covering the entire backward quadrant continuously.

High-performance lens antenna using high refractive index metamaterials

In this paper, a high refractive index metamaterial （HRM）, whose element is composed of bilayer square patch （BSP） spaced by a dielectric plate, is proposed. By reducing the thickness of the dielectric plate and the gap between adjacent patches, the BSP can effectively enhance capacitive coupling and simultaneously suppress diamagnetic response, which significantly increases the refractive index of the proposed metamaterial. Furthermore, the high refractive index region is far away from the resonant region of the metamaterial, resulting in broadband. Based on these characteristics of BSP, a gradient refractive index （GRIN） lens with thin thickness （0.34/~0, where 2~0 is the wavelength at 5.75 GHz） is designed. By using this lens, we then design a circularly polarized horn antenna with high performance. The measurement results show that the 3-dB axial ratio bandwidth is 34.8% （4.75 GHz-6.75 GHz） and the antenna gain in this frequency range is increased by an average value of 3.4 dB. The proposed method opens up a new avenue to design high-performance antenna.

Double Negative Left-Handed Metamaterials for Miniaturization of Rectangular Microstrip Antenna

In this paper, I have explored a significant concept for the miniaturization of microstrip patch antenna configuration by using the double negative (DNG) left-handed Metamaterials, which have dielectric permittivity and magnetic permeability both negative, simultaneously. It is achieved through the concept of phase-compensation by thin slab consist of the double positive (DPS) material, which have dielectric permittivity and magnetic permeability both positive, simultaneously and DNG metamaterials as a substrate of the microstrip patch antenna. By combining the DNG metamaterial slab with the slab made of DPS materials form a cavity resonator whose dispersion relation is independent of the sum of thickness of the slabs filling this cavity but it depends on the ratio of their thicknesses. This cavity constitutes by DPS and DNG material is used as substrate of the microstrip antennas and the DNG material slab is behave as phase compensator.

Edge Port Excited Metamaterial Based Patch Antennas for 5G Application

Microstrip Patch Antenna is a narrowband antenna fabricated by etching the antenna element pattern in metal trace of elements like copper bonded to an insulating dielectric substrate with a continuous metal layer on the opposite side of the substrate which forms a ground plane. Electromagnetic Metamaterial is an artificial material that is made up of different types of structural designs on dielectric substrates. In this paper, a broad and elite investigation is being carried out by designing and simulating a single negative metamaterial cell comprising a square split ring resonator. This metamaterial cell depicts negative values of permeability for a specific range of frequencies. These cells show exceptionally great applications in the design of microstrip patch antenna. The substrate of the microstrip patch antenna with a ground plane is loaded with a square split-ring resonator, Conventional and proposed patch antennas are simulated, analyzed, and reported for performance comparison of its parameters. The proposed edge port feed metamaterial based Rectangular microstrip patch antenna and Circular patch antenna designed at 26 GHz resonance frequency useful for 5G applications. Both antennas are designed on RT Duroid 5880 Substrate with 2.2, dielectric constants. The parameters such as bandwidth, gain and return loss of metamaterial loaded rectangular microstrip patch antenna and Circular patch antenna increases considerably compared to conventional antennas. Comparing parameters of both antennas, the performance of the rectangular microstrip patch antenna is found to be better than circular patch antenna.

Electromagnetic coupling reduction in dual-band microstrip antenna array using ultra-compact single-negative electric metamaterials for MIMO application

In this paper, an ultra-compact single negative（SNG） electric waveguided metamaterial（WG-MTM） is first investigated and used to reduce the mutual coupling in E ＆ H planes of a dual-band microstrip antenna array. The proposed SNG electric WG-MTM unit cell is designed by etching two different symmetrical spiral lines on the ground, and has two stopbands operating at 1.86 GHz and 2.40 GHz. The circuit size is very compact, which is only λ_0/33.6 ×λ_0/15.1（where λ_0 is the wavelength at 1.86 GHz in free space）. Taking advantage of the dual-stopband property of the proposed SNG electric WG-MTM, a dual-band microstrip antenna array operating at 1.86 GHz and 2.40 GHz with very low mutual coupling is designed by embedding a cross shaped array of the proposed SNG electric WG-MTM. The measured and simulated results of the designed dual-band antenna array are in good agreement with each other, indicating that the mutual coupling of the fabricated dual-band antenna array realizes 9.8/11.1 d B reductions in the H plane, 8.5/7.9 d B reductions in the E plane at1.86 GHz and 2.40 GHz, respectively. Besides, the distance of the antenna elements in the array is only 0.35 λ_0（where λ_0 is the wavelength at 1.86 GHz in free space）. The proposed strategy is used for the first time to reduce the mutual coupling in E ＆ H planes of the dual-band microstrip antenna array by using ultra-compact SNG electric WG-MTM.

Metamaterials and Metamaterial-Based Antenna Technology

The study of metamaterials is among the most important and attractive topics of the electromagnetic field theory and applications in the past 15 years.Much effort has been devoted to scientific research into the new physical phenomena with great progress.This paper presents the thoughts about the applications of metamaterials in innovative antenna designs from an engineering perspective.The new understanding of metamaterials offers us great possibility to translate the physical concepts of metamaterials in laboratories to innovative antenna designs in practical engineering applications.The technologies have been successfully developed,significantly improving key performances of antennas at microwave and millimeter-wave bands.The recently invented metamaterial-based antennas demonstrate not only wide operating bandwidth,high antenna efficiency,high gain,but also significantly reduced volume with simple mechanical structures.

Metamaterials技术及其天线应用综述

Metamaterials技术的一些独特电磁特性为克服当前天线、通信等领域遇到的一些技术上的限制提供了可能的解决方案。首先述评了目前文献中经常见到的一些Metamaterials的概念及其电磁特性;其次,重点综述了电磁带隙这一代表性技术的分析方法、分析模型及其在天线中应用;最后讨论了Metamaterials技术的国内外研究现状及发展方向。

An Optimized Ensemble Model for Prediction the Bandwidth of Metamaterial Antenna

Metamaterial Antenna is a special class of antennas that uses metamaterial to enhance their performance.Antenna size affects the quality factor and the radiation loss of the antenna.Metamaterial antennas can overcome the limitation of bandwidth for small antennas.Machine learning(ML)model is recently applied to predict antenna parameters.ML can be used as an alternative approach to the trial-and-error process of finding proper parameters of the simulated antenna.The accuracy of the prediction depends mainly on the selected model.Ensemble models combine two or more base models to produce a better-enhanced model.In this paper,a weighted average ensemble model is proposed to predict the bandwidth of the Metamaterial Antenna.Two base models are used namely:Multilayer Perceptron(MLP)and Support Vector Machines(SVM).To calculate the weights for each model,an optimization algorithm is used to find the optimal weights of the ensemble.Dynamic Group-Based Cooperative Optimizer(DGCO)is employed to search for optimal weight for the base models.The proposed model is compared with three based models and the average ensemble model.The results show that the proposed model is better than other models and can predict antenna bandwidth efficiently.

Optimized Ensemble Algorithm for Predicting Metamaterial Antenna Parameters

Metamaterial Antenna is a subclass of antennas that makes use of metamaterial to improve performance.Metamaterial antennas can overcome the bandwidth constraint associated with tiny antennas.Machine learning is receiving a lot of interest in optimizing solutions in a variety of areas.Machine learning methods are already a significant component of ongoing research and are anticipated to play a critical role in today’s technology.The accuracy of the forecast is mostly determined by the model used.The purpose of this article is to provide an optimal ensemble model for predicting the bandwidth and gain of the Metamaterial Antenna.Support Vector Machines(SVM),Random Forest,K-Neighbors Regressor,and Decision Tree Regressor were utilized as the basic models.The Adaptive Dynamic Polar Rose Guided Whale Optimization method,named AD-PRS-Guided WOA,was used to pick the optimal features from the datasets.The suggested model is compared to models based on five variables and to the average ensemble model.The findings indicate that the presented model using Random Forest results in a Root Mean Squared Error(RMSE)of(0.0102)for bandwidth and RMSE of(0.0891)for gain.This is superior to other models and can accurately predict antenna bandwidth and gain.

A new patch antenna with metamaterial cover

A metamaterial was introduced into the cover of a patch antenna and its band structure was analyzed. The metama- terial cover with correct selection of the working frequency increases by 9.14 dB the patch antenna’s directivity. The mechanism of metamaterial cover is completely different from that of a photonic bandgap cover. The mechanism of the metamaterial cover, the number of the cover’s layers, and the distance between the layers, were analyzed in detail. The results showed that the metamaterial cover, which works like a lens, could effectively improve the patch antenna’s directivity. The physical reasons for the improvement are also given.

The research of high-directive anisotropic magnetic metamaterial antenna loaded with frequency-selective surface

This paper uses a Computer Simulation Technology microwave studio to simulate the performance of a new highdirectivity anisotropic magnetic metamaterial antenna loaded with a frequency-selective surface. Frequency-selective surface with cross-dipole element has a great effect on the directivity, radiation pattern, and gain of such an antenna. The experimental results show that frequency-selective surface （FSS） significantly improve the radiation performance of anisotropic magnetic metamaterial antenna. For example, as a single anisotropic magnetic metamaterial antenna, half power beam width is 4 degrees in the H planes, and the gain of this antenna is 19.5dBi at 10CHz, achieving a 2.1 degree increment in half power beam width, and a 7.3 dB gain increment by loading with the FSS reflector. The simulating results are consistent with our experimental results.

Robust Prediction of the Bandwidth of Metamaterial Antenna Using Deep Learning

The design ofmicrostrip antennas is a complex and time-consuming process,especially the step of searching for the best design parameters.Meanwhile,the performance ofmicrostrip antennas can be improved usingmetamaterial,which results in a new class of antennas called metamaterial antenna.Several parameters affect the radiation loss and quality factor of this class of antennas,such as the antenna size.Recently,the optimal values of the design parameters of metamaterial antennas can be predicted using machine learning,which presents a better alternative to simulation tools and trialand-error processes.However,the prediction accuracy depends heavily on the quality of the machine learning model.In this paper,and benefiting from the current advances in deep learning,we propose a deep network architecture to predict the bandwidth of metamaterial antenna.Experimental results show that the proposed deep network could accurately predict the optimal values of the antenna bandwidth with a tiny value of mean-square error(MSE).In addition,the proposed model is comparedwith current competing approaches that are based on support vector machines,multi-layer perceptron,K-nearest neighbors,and ensemble models.The results show that the proposed model is better than the other approaches and can predict antenna bandwidth more accurately.

Optimized Two-Level Ensemble Model for Predicting the Parameters of Metamaterial Antenna

Employing machine learning techniques in predicting the parameters of metamaterial antennas has a significant impact on the reduction of the time needed to design an antenna with optimal parameters using simulation tools.In this paper,we propose a new approach for predicting the bandwidth of metamaterial antenna using a novel ensemble model.The proposed ensemble model is composed of two levels of regression models.The first level consists of three strong models namely,random forest,support vector regression,and light gradient boosting machine.Whereas the second level is based on the ElasticNet regression model,which receives the prediction results from the models in the first level for refinement and producing the final optimal result.To achieve the best performance of these regression models,the advanced squirrel search optimization algorithm(ASSOA)is utilized to search for the optimal set of hyper-parameters of each model.Experimental results show that the proposed two-level ensemble model could achieve a robust prediction of the bandwidth of metamaterial antenna when compared with the recently published ensemble models based on the same publicly available benchmark dataset.The findings indicate that the proposed approach results in root mean square error(RMSE)of(0.013),mean absolute error(MAE)of(0.004),and mean bias error(MBE)of(0.0017).These results are superior to the other competing ensemble models and can predict the antenna bandwidth more accurately.