scholarly journals Radiation-Scattering–Integrated Design of Multi-Functional Metasurfaces Based on Antenna-Embedded Substrates

2022 ◽  
Vol 8 ◽  
Author(s):  
Xinmin Fu ◽  
Ya Fan ◽  
Yajuan Han ◽  
Jiafu Wang ◽  
Zhuangzhuang Wang ◽  
...  
Keyword(s):  
Antenna Array ◽  
High Efficiency ◽  
Design Method ◽  
Structural Parameters ◽  
Ground Plane ◽  
Integrated Design ◽  
Frequency Selective Surface ◽  
Dielectric Substrate ◽  
Substrate Thickness ◽  
Radiation Scattering

The integration of the metasurface and antenna has brought new vitality to function integration and performance improvement for metasurfaces. In this study, we propose a radiation-scattering–integrated (RSI) design method of functional metasurfaces by incorporating antenna radiators into the substrates. The antenna radiators can also be considered as a band-stop frequency selective surface (FSS) embedded within the dielectric substrate, which adds up to the degree of freedom (DOF) in tailoring electromagnetic (EM) properties of the substrate. In this way, not only radiation function is added to the metasurfaces but also the original scattering-manipulation function is augmented. As an example, we apply this method to the design of a metasurface that can achieve a high radiation gain in-band and low-RCS out-of-band simultaneously. An antenna array was first designed, which uses circular patches as the radiators. Then, the antenna array was used as the substrate of a typical polarization conversion (PC) metasurface. The circular patch lies between the ground plane and the PC meta-atom, providing optimal electrical substrate thickness for PC at two separate bands. By adjusting structural parameters, the operating band of the antenna array can be made to lie in between the two PC bands. In this way, the metasurface can simultaneously possess high-gain radiation function in-band and high-efficiency PC function for RCS reduction out-of-band. A prototype was fabricated and measured. Both the simulated and measured results show that the metasurface can achieve satisfactory radiation gain in-band and significant RCS reduction out of band. This work provides an alternative method of designing multi-functional metasurfaces, which may find applications in smart skins and others.

scholarly journals Suppression of Mutual Coupling Between Two Microstrip Patch Antennas using a Sophisticated Non-Linear DGS Structure for High Frequency Wave Applications

2018 ◽  
Vol 10 (1) ◽  
pp. 161-184 ◽  
Author(s):  
Lavesh Gupta ◽  
Arun Dev Dhar Dwivedi
Keyword(s):  
Antenna Array ◽  
Mutual Coupling ◽  
Ground Plane ◽  
Microwave Frequency ◽  
Critical Issue ◽  
Dielectric Substrate ◽  
Defected Ground Structure ◽  
Frequency Wave ◽  
Main Motive ◽  
Bottom Side

Purpose – If the two or more than two antennas are present in the antenna array, the mutual coupling between them becomes a critical issue to deal with. At microwave frequency, microstrip design is often used as a transmission line because of its good performance in transferring the energy and microwave signals. Most commonly used microstrip antenna has similar structure as that of the microstrip line. On one side of dielectric substrate layer, is an extremely thin layer of conductor that forms the radiating elements and on bottom side is the ground plane made up of metallic material. Our main motive is to maintain mutual coupling suppressing structure to its simplest form. Methodology/approach/design – We therefore use a Defected Ground Structure (DGS), which greatly decreases the mutual coupling between the two antennas, thus enhancing the performance of the antenna array. Findings – The introduction of the DGS does not affect the characteristics of antenna array system. The Simulation is done using CST (Computer Simulation Technology) software and the results are tested using Vector Network Analyzer. Both the simulated and measured results are in good agreement. The coupling has been reduced from -22 to -37 dB. The recent boom in wireless industry has led to the demand for the multiband antennas.

scholarly journals An Ultrathin Graphite Based Absorber for Wearable Applications

2021 ◽  
Author(s):  
Avinash ◽  
Nisha Gupta
Keyword(s):  
Low Cost ◽  
Ground Plane ◽  
Frequency Selective Surface ◽  
Dielectric Substrate ◽  
Experimental Models ◽  
Unit Cell ◽  
Prototype Model ◽  
Angle Of Incidence ◽  
Wearable Electronics ◽  
High Frequency Structure Simulator

Abstract In this paper, a low-cost, flexible, ultrathin absorber comprising a simple square patch-shaped frequency selective surface (FSS) is proposed for wearable applications. The FSS based absorbing structure contains periodic graphite patch pattern placed on a thin paper substrate, and backed with a copper foil-based ground plane. The dimension and periodicity of the unit cell are 0.31λo and 0.36λo respectively, while the thickness of the absorber is approximately λo/85, where λo is the wavelength of free space at 10 GHz. The characteristics of the FSS absorber is optimized in terms of unit cell periodicity, and dielectric substrate height using a full-wave high frequency structure simulator software (HFSS). The effects of the parameters are also examined using equivalent circuit approach. The proposed absorber shows insensitivity towards the angle of incidence as well as angle of polarization. Finally, a prototype model is fabricated, measured, and validated with simulation results. A good agreement is depicted between simulated and experimental models. The proposed absorber finds application in the field of wearable electronics, medical, and automotive applications for effective mitigation of the EMI.

scholarly journals Design of Wideband Antenna Array with Dielectric Lens and Defected Ground Structure

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2066
Author(s):  
Jinhang Wang ◽  
Wenjie Cui ◽  
Yang Zhou ◽  
Ruipeng Liu ◽  
Mengjun Wang ◽  
...  
Keyword(s):  
Antenna Array ◽  
Mutual Coupling ◽  
Design Method ◽  
Ground Plane ◽  
Experimental Results ◽  
Defected Ground Structure ◽  
Ground Structure ◽  
Dielectric Lens ◽  
Feed Network ◽  
Element Array

In order to increase the gain of an end-fire antenna array and improve its broadband characteristics, techniques using a dielectric lens and defected ground structure have been investigated in this paper. The element of the array was constructed using an antipodal tapered slot, and two pairs of U-slots were symmetrically cut on the edges of the two antipodal fins to obtain better performance regarding impedance and radiation in the wider band. While loading an ellipse dielectric lens onto each element, the direction and gain were enhanced at the higher frequency. Meanwhile, a defected ground structure was added on the ground plane to decline the mutual coupling of adjacent radiation arms. This design method was verified by a four-element array and a four-way Wilkinson power divider was used as a feed network. Finally, a fabricated sample was tested. Experimental results showed the designed array was available.

Integrated Design and Multi-Objective Optimization of a Single Stage Heat-Pump Turbocompressor

2013 ◽  
Author(s):  
J. Schiffmann
Keyword(s):  
Design Optimization ◽  
High Efficiency ◽  
Integrated Design ◽  
Heat Pumps ◽  
Small Scale ◽  
Multi Objective Optimization ◽  
Design Constraints ◽  
Multi Objective ◽  
Wide Range ◽  
Standard Design

Small scale turbomachines in domestic heat pumps reach high efficiency and provide oil-free solutions which improve heat-exchanger performance and offer major advantages in the design of advanced thermodynamic cycles. An appropriate turbocompressor for domestic air based heat pumps requires the ability to operate on a wide range of inlet pressure, pressure ratios and mass flows, confronting the designer with the necessity to compromise between range and efficiency. Further the design of small-scale direct driven turbomachines is a complex and interdisciplinary task. Textbook design procedures propose to split such systems into subcomponents and to design and optimize each element individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported, direct driven turbocompressors for applications with challenging requirements with regards to operation range and efficiency. Using previously validated reduced order models for the different components an integrated model of the compressor is implemented and the optimum system found via multi-objective optimization. It is shown that compared to standard design procedure the integrated approach yields an increase of the seasonal compressor efficiency of more than 12 points. Further a design optimization based sensitivity analysis allows to investigate the influence of design constraints determined prior to optimization such as impeller surface roughness, rotor material and impeller force. A relaxation of these constrains yields additional room for improvement. Reduced impeller force improves efficiency due to a smaller thrust bearing mainly, whereas a lighter rotor material improves rotordynamic performance. A hydraulically smoother impeller surface improves the overall efficiency considerably by reducing aerodynamic losses. A combination of the relaxation of the 3 design constraints yields an additional improvement of 6 points compared to the original optimization process. The integrated design and optimization procedure implemented in the case of a complex design problem thus clearly shows its advantages compared to traditional design methods by allowing a truly exhaustive search for optimum solutions throughout the complete design space. It can be used for both design optimization and for design analysis.

scholarly journals A Graphene-Assembled Film Based MIMO Antenna Array with High Isolation for 5G Wireless Communication

2021 ◽  
Vol 11 (5) ◽  
pp. 2382
Author(s):  
Rongguo Song ◽  
Xiaoxiao Chen ◽  
Shaoqiu Jiang ◽  
Zelong Hu ◽  
Tianye Liu ◽  
...  
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
Multiple Input Multiple Output ◽  
Frequency Selective Surface ◽  
Antenna System ◽  
Antenna Element ◽  
Mimo Antenna ◽  
High Isolation ◽  
Input Multiple Output ◽  
Alternative Material

With the development of 5G, Internet of Things, and smart home technologies, miniaturized and compact multi-antenna systems and multiple-input multiple-output (MIMO) antenna arrays have attracted increasing attention. Reducing the coupling between antenna elements is essential to improving the performance of such MIMO antenna system. In this work, we proposed a graphene-assembled, as an alternative material rather than metal, film-based MIMO antenna array with high isolation for 5G application. The isolation of the antenna element is improved by a graphene assembly film (GAF) frequency selective surface and isolation strip. It is shown that the GAF antenna element operated at 3.5 GHz has the realized gain of 2.87 dBi. The addition of the decoupling structure improves the isolation of the MIMO antenna array to more than 10 dB and corrects the antenna radiation pattern and operating frequency. The isolation between antenna elements with an interval of 0.4λ is above 25 dB. All experimental results show that the GAF antenna and decoupling structure are efficient devices for 5G mobile communication.

scholarly journals Triangular Slot-Loaded Wideband Planar Rectangular Antenna Array for Millimeter-Wave 5G Applications

Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 778
Author(s):  
Iftikhar Ahmad ◽  
Houjun Sun ◽  
Umair Rafique ◽  
Zhang Yi
Keyword(s):  
Antenna Array ◽  
Millimeter Wave ◽  
Communication Systems ◽  
Ground Plane ◽  
Simulated Data ◽  
Impedance Bandwidth ◽  
Antenna Element ◽  
Single Antenna ◽  
Rectangular Patch ◽  
Half Power

This paper presents a design of a triangular slot-loaded planar rectangular antenna array for wideband millimeter-wave (mm-wave) 5G communication systems. The proposed array realizes an overall size of 35.5 × 14.85 mm2. To excite the array elements, a four-way broadband corporate feeding network was designed and analyzed. The proposed array offered a measured impedance bandwidth in two different frequency ranges, i.e., from 23 to 24.6 GHz and from 26 to 45 GHz. The single-antenna element of the array consists of a rectangular patch radiator with a triangular slot. The partial ground plane was used at the bottom side of the substrate to obtain a wide impedance bandwidth. The peak gain in the proposed array is ≈12 dBi with a radiation efficiency of >90%. Furthermore, the array gives a half-power beamwidth (HPBW) of as low as 12.5°. The proposed array has been fabricated and measured, and it has been observed that the measured results are in agreement with the simulated data.

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