PIER M | PIER Journals

2024-09-13

PIER M

Vol. 128, 145-153, 2024

download: 71

Two-Port Hexagon-Shaped MIMO Antenna for UWB Applications Integrated with Four Frequently-Used Stopbands for Medical Domains

Liangliang Zhao , Aidong Li , Yongmao Wang , Dengyang Song , Mingxuan Zheng , Chenlu Liu , Chuwei Li , Yongtao Liang , Huiling Zhao and Chufeng Hu

A compact ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna with four stopbands is designed and experimentally investigated. By the method of coating, various T-shaped structures and split-ring resonators (SRRs) are used for suppressing the mutual coupling and introducing the band-notched characteristics, respectively. The actual design has an overall size of 46 × 37 × 1.57 mm³ across the whole UWB spectrum from 2 to 22 GHz except stopbands from 3.47 to 3.83 GHz, 5.2 to 5.85 GHz, 7.19 to 7.84 GHz, and 8.15 to 8.6 GHz, which prevent the interference of Microwave Access (WiMax), wireless local area network (WLAN), satellite downlink and satellite communications band (ITU 8 GHz) bands, respectively. Besides, the isolation of the most operating frequencies is higher than 20 dB, and the antenna obtains a fairly stable radiation pattern and gain, as well as a lower envelope correlation coefficient (ECC < 0.005). Additionally, using the antenna inserted in name badge of the doctor, the chance of infection will be greatly reduced. Ultimately, the proposed MIMO monopole antenna has a potential application in the medical domain.

Two-port Hexagon-shaped MIMO Antenna for UWB Applications Integrated with Four Frequently-used Stopbands for Medical Domains

2024-09-07

PIER M

Vol. 128, 135-144, 2024

doi:10.2528/PIERM24062805

download: 108

Artificial Magnetic Conductor Based Improved Radiation Properties of Fractal MIMO Antenna for UWB Applications

Deshpande Ramesh , Yalavarthi Usha Devi and Boddapati Taraka Phani Madhav

A novel artificial magnetic conductor (AMC) structure as a reflector is presented to enhance the gain of a fractal ultra-wideband (UWB) multi-input multi-output (MIMO) antenna. Unit cell of proposed AMC structure is achieved through 4 iterations to obtain better characteristics as reflector. An in-phase reflection from 2-16 GHz is achieved by the unit cell. The proposed AMC structure 6 × 6 array and 6 × 12 array are examined with single element and 2 element fractal MIMO antennas respectively. The fractal MIMO antenna backed with an AMC structure achieved an operating band from 2.2 to 15.8 GHz, and the isolation between the elements is greater than 23 dB. The proposed AMC is structure is fabricated, and experimental results are analysed in comparison with simulation ones. An average gain improvement of 6.1 dB is observed by the proposed AMC structure in the operating band. Surface current distributions, EM fields, and radiation patterns are investigated at various frequencies. MIMO performance parameters such as diversity gain, total active reflection coefficient, envelope correlation coefficient, and channel capacity loss characteristics are analyzed in this paper. The fractal MIMO antenna backed with an AMC structure exhibits good diversity performance characteristics with improved radiation properties for UWB applications.

Artificial Magnetic Conductor Based Improved Radiation Properties of Fractal MIMO Antenna for UWB Applications

2024-09-02

PIER M

Vol. 128, 127-134, 2024

doi:10.2528/PIERM24070404

download: 144

3D-Printing of Slanted Corrugated Horn Antennas for the E-Band

Markus Tafertshofer , Maximilian Binder and Erwin M. Biebl

In this paper, the feasibility of using additive manufacturing (AM) technologies for the fabrication of corrugated horn antennas for the E-band (60 to 90 GHz) is investigated. Stereolithography apparatus (SLA) and selective laser melting (SLM) are identified as the most suitable technologies for manufacturing horn antennas in this frequency range. To ensure good manufacturing, slanted corrugations are utilized. The antennas have a gain of 13 dBi at 72 GHz and are designed in CST Microwave Studio. For the fabrication of the plastic parts, SLA and the finer-scaled projection micro stereolithography (PμSL) technology are applied. The metal antennas are printed with direct metal laser sintering (DMLS) from the aluminum alloy AlSi₁₀Mg and the finer scaled micro metal laser sintering (μMLS) from 316L stainless steel. Overall, four antennas are fabricated. The plastic antennas are plated with copper. Dimensional tolerances and surface roughness of the antennas are evaluated. The antennas are investigated considering H- and E-plane beam shapes, input reflection, and realized gain. The measurement is conducted in an anechoic chamber using the Single-Antenna method. The μMLS antenna supplies the best results.

3D-printing of Slanted Corrugated Horn Antennas for the E-band

2024-08-28

PIER M

Vol. 128, 115-125, 2024

doi:10.2528/PIERM24072701

download: 160

Design of a 3D Printed Wide Band Metasurface Antenna for High Power Applications

Mohamed Z. M. Hamdalla , Mashrur Zawad , Matthew Kunkle , Somen Baidya , Roy C. Allen , Peter J. Bland , Travis D. Fields and Ahmed M. Hassan

Weight-size optimization is the main challenge of high-power antenna design. This paper presents a low-profile, metasurface-based wideband antenna. The proposed antenna comprises an N-type-to-waveguide transition to excite the metasurfaces and handle high-power excitations. A metasurface array of 4×4-unit cells is integrated into the waveguide. The proposed waveguide is 3D printed, and its internal faces are covered by copper tape to maintain a low weight (less than 200 g). The prototype is experimentally tested, and the results confirm the prototype's functionality from 2.1 GHz to 3.6 GHz with a bandwidth of 52.6% and a peak gain of 8.5 dBi. Furthermore, the high-power handling capability of the proposed design has been experimentally confirmed by exciting it with a 7 kV pulsed source. These results demonstrate the applicability of the proposed antenna in satellite communication, radar applications, and wireless communication between Unmanned Aerial Vehicles (UAVs).

Design of a 3D Printed Wide Band Metasurface Antenna for High Power Applications

2024-08-26

PIER M

Vol. 128, 99-113, 2024

doi:10.2528/PIERM24062603

download: 442

Numerical Modeling of GPR for Underground Multi-Pipes Detection by Combining GprMax and Deep Learning Model

Qiang Guo , Peng-Ju Yang , Rui Wu and Yuqiang Zhang

As a popular nondestructive technique, ground penetrating radar (GPR) is extensively utilized for detecting underground pipelines. In this paper, an efficient and automatic scheme is presented for the detection and classification of underground pipelines by combining electromagnetic modeling and machine learning techniques. By virtue of open-source gprMax software, the B-Scan signatures of underground pipelines are simulated and analyzed in detail, with four types of underground pipelines taken into account, i.e., iron pipelines, concrete pipelines, copper pipelines, and PVC pipelines. On the basis of electromagnetic modeling, B-scan profiles of underground pipelines are preprocessed by using the average method and time gain compensation method to obtain a dataset for training neural network of YOLOv8 model. The simulations indicate that our scheme combining simulated B-Scan profiles and YOLOv8 model is able to detect and classify underground pipelines with high accuracy, and the category and material of underground pipelines can be determined with a high confidence level. Specifically, the detection time of a single B-scan image for underground pipelines is about 0.02s, and the average detection accuracy can reach 0.995, which is potentially valuable for the automatic detection and classification of underground pipelines in GPR applications.

Numerical Modeling of GPR for Underground Multi-pipes Detection by Combining GprMax and Deep Learning Model

2024-08-25

PIER M

Vol. 128, 89-98, 2024

doi:10.2528/PIERM24070803

download: 239

Compact Dual-Band BPF Based on Loaded SIW with Meandered Slot Line for 5G and Beyond Applications

Hasan Al-Darraji and Hussam Al-Saedi

In this paper, a meandered slot line (MSL) is proposed to miniaturize a substrate-integrated waveguide (SIW) band-pass filter (BPF) and independently realize a dual-band response. The suggested MSL is symmetrically etched on the upper layer of the SIW resonator; hence, maximum space utilization is realized to increase the miniaturization factor. The TE₁₀₁ and TE₁₀₂ modes were excited and controlled independently through the size and shape of the MLS to highly perturbate the electric field distribution inside the SIW cavity. A systematic procedure was employed to design the proposed dual-band SIW-BPF at the desired specifications. Ansys EDT (2022 R1) full wave simulator was used to analyze and optimize the proposed second-order dual-band BPF. The suggested filter was fabricated using printed circuit board technology on Rogers RO4003 with a dielectric constant (ε_r = 3.55). The proposed MSL-SIW structure achieved an overall miniaturization of 68.3% at the lower band compared to the conventional SIW filter, where the resonance frequency of the TE₁₀₁ shifted from 16.43 GHz to 4.61 GHz. The overall area of the proposed filter is 0.08λ_g² at 4.61 GHz with a physical length of 14 mm and width of 7 mm. The operating dual bands are centered at 4.61 GHz for the first band and 6.91 GHz for the second band, with fractional bandwidths of 7.6% and 3.6%, respectively. Measurement results, which highly match the simulation findings, achieved a return loss (RL) of 25 dB and 18 dB and an insertion loss (IL) of 0.95 dB and 1.5 dB for the first and second bands, respectively. Accordingly, a simple, low IL, and compact SIW-based BPF was realized, making it an excellent candidate for 5G and beyond applications.

Compact Dual-band BPF Based on Loaded SIW with Meandered Slot Line for 5G and Beyond Applications

2024-08-24

PIER M

Vol. 128, 83-88, 2024

doi:10.2528/PIERM24071701

download: 176

A Lightweight Deep Learning Model for Full-Wave Nonlinear Inverse Scattering Problems

Yixin Xia and Siyuan He

Nowadays, deep learning schemes (DLSs) have gradually become one of the most important tools for solving inverse scattering problems (ISPs). Among DLSs, the dominant current scheme (DCS), which extracts physical features from the dominant components of the induced currents, has shown its successes by simplifying the learning process in solving ISPs. It has shown excellent performance in terms of efficiency and accuracy, but the increasing number of channels in DCS often requires higher computational costs and memory usage. In this paper, a lightweight deep learning model for DCS is proposed to reduce the burden of memories in the training and testing processes of network structure. And extensive tests of the model are conducted, where comparisons with results from the U-Net structure are provided. The comparison results validate its potential application in utilizing DCS under limited resource conditions.

A Lightweight Deep Learning Model for Full-wave Nonlinear Inverse Scattering Problems

2024-08-14

PIER M

Vol. 128, 71-82, 2024

doi:10.2528/PIERM24050702

download: 311

Millimeter-Wave Quasi-Elliptic Filters in Groove Gap Waveguide Technology Using Overmoded Cavity with Spurious Coupling Suppression for Next-Generation SATCOM Applications

Rajni Kant , Deepak Ghodgaonkar , Abhishek Jindal , Parthasarathi Samanta , Hitesh Modi and Praveen Kumar Ambati

This paper addresses the issue of sidelobe imbalance due to spurious coupling in quasi-elliptic filters designed in groove gap waveguide (GGW) technology using TE₁₀₂ overmoded cavity based resonator to realize the cross coupling in the cascaded quadruplet topology. The filter is designed at 38 GHz with 750 MHz bandwidth (1.97% fractional bandwidth) to demonstrate its potential as a narrow-band, high-power output filter at mm-wave frequencies in next-generation high throughput satellites. The filter is designed for production yield avoiding any complex structures to realize the negative cross coupling and using an all-capacitive iris structure. Systematic studies have been performed to identify and mitigate the sidelobe imbalance issue, and a final design has been proposed with a very low (<1 dB) sidelobe imbalance. The measured results of the realized hardware closely match simulated ones. The proposed design configuration is an ideal filter option for next generation SATCOM applications as it provides benefits of narrowband symmetrical frequency response with low insertion loss, sharp near band rejection, and high-power handling capability along with the benefits of gap waveguide technology in terms of ease of fabrication, low passive intermodulation (PIM) level, and low sensitivity towards surface imperfections and misalignment issues.

Millimeter-wave Quasi-elliptic Filters in Groove Gap Waveguide Technology Using Overmoded Cavity with Spurious Coupling Suppression for Next-generation SATCOM Applications

2024-08-14

PIER M

Vol. 128, 61-69, 2024

doi:10.2528/PIERM24060603

download: 243

Designing Magnetic Coupler of Static Wireless Power Transfer System for Thermal Reduction by Using Silicon-Cobalt Wafer

Umar Farooq , Jiropast Suakaew , Poramed Wongjom , Latif Jan , Maryam and Wanchai Pijitrojana

Wireless power transfer (WPT) for electric vehicles (EV) is a promising technology that can help with e-mobility because of its convenience and ability to reduce range anxiety issues. The safety concerns of such systems have received a lot of attention recently. Magnetic coupler is the most important component of WPT systems in terms of thermal safety as its temperature rises because of power outages during the charging process, which could cause damage to the surroundings and other components associated with the system. This article proposes a new thermal and magnetic coupler design by utilizing a Silicon-Cobalt wafer using the Spin Seebeck effect (SSE) phenomenon fabricated through the sputtering technique which can enhance the efficiency of the transmission coil as well as act as a heat exchanger to remove the heat from the coil as well as reduce temperature with the design model.

Designing Magnetic Coupler of Static Wireless Power Transfer System for Thermal Reduction by Using Silicon-Cobalt Wafer

2024-08-09

PIER M

Vol. 128, 51-59, 2024

doi:10.2528/PIERM24060507

download: 283

High-Isolation Compact MIMO Antenna with Distributed Metamaterial Loading

Zhi Song , Shucheng Zhao , Siqi Li , Jiayi Chen and Yanbing Xue

This paper details the design and realization of a high-isolation multiple-input-multiple-output (MIMO) antenna tailored for fifth-generation (5G) wireless applications. The antenna consists of a 2-element array, with each unit being a patch antenna loaded with six uniformly sized complementary split-ring resonators (CSRRs). These CSRRs are strategically etched to minimize the antenna's overall size. In addition, the fragment-type split ring resonators (SRRs) are horizontally positioned between the antenna units to further improve isolation. The placement and structure of these fragment-type SRRs are optimized through a combined use of High-Frequency Structure Simulator (HFSS) and genetic algorithm (GA) techniques, which enables significant isolation levels exceeding -40 dB between antenna units. The proposed MIMO antenna operates within the 5G C-band with a -10 dB bandwidth ranging from 4.84 to 5.00 GHz, while the isolation at 4.9 GHz improves from 14.73 dB to 42.88 dB. Moreover, the maximum Envelope Correlation Coefficient is 0.002, and the antenna dimensions are 50 mm × 44 mm × 1.6 mm. Antenna samples are fabricated using wet etching on an FR4 substrate. The measured and simulated values are found to be in good agreement. Compared to the traditional antenna design method, which relies on parameters sweeping, the algorithmic approach used in this paper significantly enhances both the design's effectiveness and efficiency.

High-isolation Compact MIMO Antenna with Distributed Metamaterial Loading

2024-08-08

PIER M

Vol. 128, 41-49, 2024

doi:10.2528/PIERM24051805

download: 278

Design of a Compact Dual Port 2 × 1 Ultra-Wideband MIMO Antenna for Radio Frequency Energy Harvesting Based on Four ``a" Shaped Slots

Amira Ali Khedr , Basem Elhady Elnaghi and Ahmed Magdy Mohamed

Radio frequency energy harvesting (RF-EH), which uses an ultra-wideband (UWB) antenna, is the best substitute for traditional batteries for continuously powering sensor networks. The UWB antenna helps to receive the ambient radio frequency energy that radiates from communication applications for harvesting purposes to power devices or recharge batteries. A novel aspect of this design is the use of dual antenna ports with four ``A" shaped in radiating patches and ground plane, which permits the harvester to completely utilize all accessible frequency bands. The design analysis of a compact dual-port (2 × 1) ultra-wideband multiple-input multiple-output (UWB-MIMO) antenna based on four ``A" shaped and shared ground plane for RF energy harvesting in the band of 2.3-21.7 GHz is presented. The proposed antenna has been implemented on a Rogers RT 5880 substrate with a size of 39 mm × 30 mm, a thickness of 0.8 mm, and a dielectric constant of 2.2. It achieves S₁₁ ≤ -10 dB at (2.3-21.7) GHz and a maximum peak gain of 10.29 dB at 20.53 GHz. The proposed antenna is designed and simulated with ANSYS HFSS and fabricated. The results of simulation and measurement of the proposed antenna are in good agreement, and the antenna achieves bandwidth of 2.3–20 GHz that supports radio frequency energy harvesting in addition to UWB applications across satellite, Wi-Fi, Wi-Max, and mobile applications.

Design of a Compact Dual Port 2 × 1 Ultra-Wideband MIMO Antenna for Radio Frequency Energy Harvesting Based on Four ``A

2024-07-25

PIER M

Vol. 128, 31-39, 2024

doi:10.2528/PIERM24030604

download: 342

Filter Design Based on Multilayer Wide Side Coupling Structure

Wu-Sheng Ji , Hanglin Du , Ying-Yun Tong , Xiaochun Ji and Liying Feng

In this paper, three kinds of filters are designed, all of which are based on the basic multi-layer structure of microstrip-slot wire-microstrip wide edge coupling. The ultra-wideband filter is realized by three-class connection. The intermediate coupling layer of coplanar waveguide and multimode resonator is designed to realize the double broadband filter. The ultra-wideband filter is realized by using a curved T SIR structure and changing the middle coupling slot structure. The purpose of this paper is to construct a stable and easy to generalize multilayer filter design method, which can achieve broadband and high selectivity, and can realize dual passbands.

Filter Design Based on Multilayer Wide Side Coupling Structure

2024-07-23

PIER M

Vol. 128, 21-30, 2024

doi:10.2528/PIERM24042403

download: 413

Convex Optimization-Based Linear and Planar Array Pattern Nulling

Tong Van Luyen , Nguyen Van Cuong and Phan Dang Hung

In the landscape of wireless communication, smart antennas, or adaptive array antennas, have emerged as vital components, offering heightened gains and spectral efficiency in advanced communication systems such as 5G and beyond. However, augmenting network coverage, capacity, and quality of service remains a pressing concern amid advancing communication technologies and escalating user demands. Array antennas with reduced sidelobe levels, high directivity, and increased beam steering capabilities are sought after to address these challenges. This paper explores convex optimization as a potent tool for array synthesis problems, offering robust performance and solution efficiency. By formulating optimization problems as convex programming, sidelobe reduction challenges can be efficiently addressed. The paper presents a comprehensive investigation into convex optimization-based approaches for array pattern nulling, assessing their performance and computational efficiency in various scenarios. Numerical examples demonstrate the efficacy of the proposed methods in maintaining the main lobe, controlling sidelobe levels, and placing nulls at interfering directions, thereby advancing the state-of-the-art in smart antenna technology.

Convex Optimization-based Linear and Planar Array Pattern Nulling

2024-07-20

PIER M

Vol. 128, 11-20, 2024

doi:10.2528/PIERM24042803

download: 345

Compact Dual-Band Antenna Based on Dual-Cap Metasurface

Xue Chen and Haipeng Dou

A novel compact dual-band antenna based on dual-cap metasurface (MS) is proposed. By etching circumferential circular ring slots on one side of the substrate and large cruciform slot on the other side, the dual-cap MS operates in two frequency bands. In addition, by placing the dual-cap MS at the back of a circular ring planar antenna which serves as a reflector, the impedance characteristic of the antenna in lower band and gain both in two bands are improved. The results show that this dual-cap MS antenna operates in the Wireless Local Area Network (WLAN) bands of 2.43-2.6 GHz and 5.48-6.05 GHz. Moreover, the maximum gains in lower and upper bands can reach 6.9 and 5.8 dBi, respectively.

2024-07-17

PIER M

Vol. 128, 1-9, 2024

doi:10.2528/PIERM23112103

download: 369

A 3-Band Iteration Method to Transfer Knowledge Learned in RGB Pretrained Models to Hyperspectral Domain

Lei Wang and Sailing He

We propose a 3-band iteration method to transfer knowledge learned from RGB (red, green and blue) data pretrained models to the hyperspectral domain. We demonstrate classification of a Multi-spectral Choledoch database for cholangiocarcinoma diagnosis. The results show quicker and more stable training progress: 92%+ top-1 accuracy in the initial 3 epochs. Some advanced training techniques in the RGB computer vision field can be easily utilized and transferred to the hyperspectral domain without adding more parameters to the original architecture. The computational cost and hardware requirements remain the same. After voting, the highest top-1 accuracy on the validation set reached 95.4%, and the highest top-1 accuracy on the test set reached 94.3%. We can directly use our models trained on high-dimensional spectral images to test and infer on RGB color images. We visualized some results by Grad-CAM (Gradient-weighted Class Activation Mapping) on RGB test data, and it shows the transferability of knowledge. We trained the models solely on classification task on spectral data, and these models showed their ability to predict on RGB images with different fields of views. The results indicate good segmentation even when the model has never been trained on any segmentation task.