Abstract This paper emphasizes on amalgamation of MIMO antenna with DRA structures; explicitly useful to wireless applications. The feeding mechanism is accomplished by the symmetrically positioned tapered Y-shape lines. The design also encompasses a CSRR geometry along with two metallic reflectors. The incorporation of CSRR introduces novel investigation into traditional designs, resulting in improved isolation performance of the MIMO design. In order to demonstrate the effectiveness of the mentioned antenna, we performed a simulation using ANSYS-HFSS. Subsequently, a physical model was developed and tested. It confirms four different resonating points as 2.56, 4.08, 5.76, and 9.12 GHz with isolations of 36, 47.3, 33.9, and 33 dB respectively. In addition, a few other important parameters relevant to MIMO have been considered and presented in the form of ECC, MEG, DG, CCL, and TARC which claim the dominancy of the stated antenna under the MIMO diversity scenario. In summary, we have presented a model that demonstrates a strong correlation between the simulated and measured outcomes.
{"title":"CIQBCP-MIMO-DRA: CSRR inspired quad band circularly polarized MIMO-DRA for W-LAN, Wi-Max, Wi-Fi (6E) and X-band applications","authors":"Satyanarayan Rath, Sheeja Kochuthundil Lalitha","doi":"10.1515/freq-2023-0281","DOIUrl":"https://doi.org/10.1515/freq-2023-0281","url":null,"abstract":"Abstract This paper emphasizes on amalgamation of MIMO antenna with DRA structures; explicitly useful to wireless applications. The feeding mechanism is accomplished by the symmetrically positioned tapered Y-shape lines. The design also encompasses a CSRR geometry along with two metallic reflectors. The incorporation of CSRR introduces novel investigation into traditional designs, resulting in improved isolation performance of the MIMO design. In order to demonstrate the effectiveness of the mentioned antenna, we performed a simulation using ANSYS-HFSS. Subsequently, a physical model was developed and tested. It confirms four different resonating points as 2.56, 4.08, 5.76, and 9.12 GHz with isolations of 36, 47.3, 33.9, and 33 dB respectively. In addition, a few other important parameters relevant to MIMO have been considered and presented in the form of ECC, MEG, DG, CCL, and TARC which claim the dominancy of the stated antenna under the MIMO diversity scenario. In summary, we have presented a model that demonstrates a strong correlation between the simulated and measured outcomes.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"40 6","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139437200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Shared-radiator design of a broadband and dual-mode antenna that simultaneously covers the VHF/UHF band and satellite navigation band is presented for personal role radio (PRR) applications. Quadrifilar helix antenna (QHA) is devised to be a circularly polarized radiator which as well acts as a part of the upper half radiation arm of the dipole antenna and be equivalent to a linearly polarized radiation current carrier at VHF/UHF band, forming a symmetrical dipole antenna with a sinusoidal current distribution. A 5th-order balanced matching network comprised of five cascade L-sections is adopted to obtain the maximum possible working band-width and a 3.76:1 band-width (116 %) at VHF/UHF band is achieved. Strong mutual coupling effect of the two operating modes is observed near 1.5 GHz originated from QHA shared-radiator design, and a new balun structure is applied to achieve high isolation and self-decoupling, subsequently |S21| of the two operating modes is significantly reduced from about −18 dB to below −32 dB at satellite navigation band without affecting the reflection coefficient and radiation efficiency. The measured results show that radiation patterns of the manufactured prototype is basically consistent with corresponding simulation counterparts.
摘要 针对个人作用无线电（PRR）应用，介绍了一种同时覆盖 VHF/UHF 波段和卫星导航波段的宽带双模天线的共用辐射器设计。四叉螺旋天线（QHA）被设计成圆极化辐射器，同时作为偶极子天线上半辐射臂的一部分，相当于 VHF/UHF 波段的线性极化辐射载流子，形成正弦电流分布的对称偶极子天线。为获得尽可能大的工作带宽，采用了由五个级联 L 段组成的五阶平衡匹配网络，在 VHF/UHF 频段实现了 3.76:1 的带宽（116%）。由于采用了 QHA 共辐射器设计，在 1.5 GHz 附近观察到了两种工作模式的强烈相互耦合效应，并采用了一种新的平衡器结构来实现高隔离和自去耦，从而在不影响反射系数和辐射效率的情况下，将两种工作模式的|S21|从卫星导航频段的-18 dB 左右显著降低到-32 dB 以下。测量结果表明，制造原型的辐射模式与相应的模拟模式基本一致。
{"title":"Shared-radiator design of broadband and dual-mode antenna for personal role radio applications","authors":"Guanjun Wang, Liang Zhu, Yayun Xie, Chao Lu","doi":"10.1515/freq-2023-0181","DOIUrl":"https://doi.org/10.1515/freq-2023-0181","url":null,"abstract":"Abstract Shared-radiator design of a broadband and dual-mode antenna that simultaneously covers the VHF/UHF band and satellite navigation band is presented for personal role radio (PRR) applications. Quadrifilar helix antenna (QHA) is devised to be a circularly polarized radiator which as well acts as a part of the upper half radiation arm of the dipole antenna and be equivalent to a linearly polarized radiation current carrier at VHF/UHF band, forming a symmetrical dipole antenna with a sinusoidal current distribution. A 5th-order balanced matching network comprised of five cascade L-sections is adopted to obtain the maximum possible working band-width and a 3.76:1 band-width (116 %) at VHF/UHF band is achieved. Strong mutual coupling effect of the two operating modes is observed near 1.5 GHz originated from QHA shared-radiator design, and a new balun structure is applied to achieve high isolation and self-decoupling, subsequently |S21| of the two operating modes is significantly reduced from about −18 dB to below −32 dB at satellite navigation band without affecting the reflection coefficient and radiation efficiency. The measured results show that radiation patterns of the manufactured prototype is basically consistent with corresponding simulation counterparts.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"52 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139437259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rotman lens beamforming networks are widely used for high gain, wide bandwidth applications in 5G communication. The uniform amplitude and phase distribution along with wide angle scanning at the array ports are mostly demanded for reducing the losses. Furthermore, minimum phase error is essential requirement for lens designs. Conventionally, for wide angle scanning, the lenses are designed by using most common expression between beam angle α and focal ratio (parameter ‘g’) i.e. g = 1 + 0.5α2. The lenses obtained by such relation are inefficient for higher beam angle such as α = 45° due to the restricted shapes of beam and array contours. Hence suffer with large path length error limitation. In this paper, the mathematical relation between beam angle and focal ratio (parameter ‘g’) has been developed. The proposed relation offers phase error reduction more than 3× than the conventional expression based lens error. The simulation of the designed lens has performed using Software MATLAB which showed close agreement with the analytical values. Furthermore, three rectangular MPA arrays at center frequency 2.35 GHz have been proposed and simulated with lens design for 5G frequency range i.e. 2.3–2.4 GHz and offer high gain, directivity and wide coverage.
{"title":"Analysis of 5G Rotman beamforming lens antenna for higher beam angle and minimum phase error","authors":"Deep Kishore Parsediya, Pramod Kumar Singhal","doi":"10.1515/freq-2023-0239","DOIUrl":"https://doi.org/10.1515/freq-2023-0239","url":null,"abstract":"Rotman lens beamforming networks are widely used for high gain, wide bandwidth applications in 5G communication. The uniform amplitude and phase distribution along with wide angle scanning at the array ports are mostly demanded for reducing the losses. Furthermore, minimum phase error is essential requirement for lens designs. Conventionally, for wide angle scanning, the lenses are designed by using most common expression between beam angle <jats:italic>α</jats:italic> and focal ratio (parameter ‘<jats:italic>g</jats:italic>’) i.e. <jats:italic>g</jats:italic> = 1 + 0.5<jats:italic>α</jats:italic> <jats:sup>2</jats:sup>. The lenses obtained by such relation are inefficient for higher beam angle such as <jats:italic>α</jats:italic> = 45<jats:italic>°</jats:italic> due to the restricted shapes of beam and array contours. Hence suffer with large path length error limitation. In this paper, the mathematical relation between beam angle and focal ratio (parameter ‘<jats:italic>g</jats:italic>’) has been developed. The proposed relation offers phase error reduction more than 3× than the conventional expression based lens error. The simulation of the designed lens has performed using Software MATLAB which showed close agreement with the analytical values. Furthermore, three rectangular MPA arrays at center frequency 2.35 GHz have been proposed and simulated with lens design for 5G frequency range i.e. 2.3–2.4 GHz and offer high gain, directivity and wide coverage.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"113 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139057627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this communication, a pyramidal horn antenna is proposed and investigated to operate in the sub-THz region at a centre frequency of 0.245 THz. The antenna has five layers such as coupling layer, air cavity layer, excitation layer, pyramidal horn, and extended side wings. The coupling layer is responsible to couple the electromagnetic (EM) wave from waveguide feed. The excitation layer consists of a plus shape slot which is responsible for the excitation of the proposed antenna. The air cavity is designed such that it can efficiently excite the plus-shaped slot of the excitation layer. In order to achieve high gain and efficiency, the pyramidal horn and the extended side wings are used in combination. The proposed horn antenna has a significant efficiency and gain of 97.1 % and 19.2 dBi respectively and gives a wide impedance bandwidth of 32.3 % (0.205–0.284 THz). When compared to the literature, the proposed novel design demonstrates significant improvement in terms of bandwidth, directivity, and gain. The antenna finds its suitability for Sub-THz 6G wireless communication.
{"title":"Sub-THz pyramidal horn antenna for 6G wireless communication","authors":"Sunil Kumar, Saurabh Kumar","doi":"10.1515/freq-2023-0114","DOIUrl":"https://doi.org/10.1515/freq-2023-0114","url":null,"abstract":"Abstract In this communication, a pyramidal horn antenna is proposed and investigated to operate in the sub-THz region at a centre frequency of 0.245 THz. The antenna has five layers such as coupling layer, air cavity layer, excitation layer, pyramidal horn, and extended side wings. The coupling layer is responsible to couple the electromagnetic (EM) wave from waveguide feed. The excitation layer consists of a plus shape slot which is responsible for the excitation of the proposed antenna. The air cavity is designed such that it can efficiently excite the plus-shaped slot of the excitation layer. In order to achieve high gain and efficiency, the pyramidal horn and the extended side wings are used in combination. The proposed horn antenna has a significant efficiency and gain of 97.1 % and 19.2 dBi respectively and gives a wide impedance bandwidth of 32.3 % (0.205–0.284 THz). When compared to the literature, the proposed novel design demonstrates significant improvement in terms of bandwidth, directivity, and gain. The antenna finds its suitability for Sub-THz 6G wireless communication.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"35 7","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138943847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents a compact implantable antenna for biomedical use in the ISM band (2.4–2.48 GHz). The antenna is designed with Roger RT/duroid 6010.2LM high permittivity substrate of thickness 0.25 mm, and feed with a 50 Ω co-axial feed. A hybrid-loop resonator slot structure and C & I-shaped slots in the radiating patch has enabled the antenna to work in the ISM band. Via less ground makes this design simple, easier to fabricate, and a suitable candidate for implantable application. The proposed antenna occupies a small volume of 0.0984 λ0 × 0.082 λ0 × 0.00468 λ0 and retained 152 MHz bandwidth (2.4077–2.5599 GHz with FBW 7.64 %) with a maximum gain of −22 dBi where λ0 is guided wavelength. The projected antenna has good performance in the multi-layer tissue model, male human head voxel model, frequency-dependent skin model, and in muscle phantom by maintaining a minimum −20 dB return-loss in the ISM band. The proposed antenna’s Device Integration using a frequency-dependent skin phantom was performed and the results are well-suited for biomedical applications in the ISM band. The bare antenna was used to study the Specific Absorption Rate (SAR) in the human scalp. Where for 1 g and 10 g tissues the investigated results are 626.05 W/kg and 84.4 W/kg for an input power of 1 W, however the input power is limited to maximum 2.55 mW (for 1 g tissue) and 23.56 mW (for 10 g tissue) to comply with IEEE SAR guidelines. The qualities of the manufactured antenna are verified in a skin-imitating gel and animal tissue that exhibits good agreement with the simulation outcomes.
本文介绍了一种用于 ISM 波段（2.4-2.48 GHz）生物医学的紧凑型植入式天线。该天线采用厚度为 0.25 毫米的 Roger RT/duroid 6010.2LM 高介电常数基板设计，馈电采用 50 Ω 同轴馈电。辐射贴片上的混合环谐振器槽结构和 C & I 形槽使天线能够在 ISM 波段工作。通过较少的接地使该设计简单、易于制造，适合植入式应用。该天线体积小，仅为 0.0984 λ 0 × 0.082 λ 0 × 0.00468 λ 0，带宽为 152 MHz（2.4077-2.5599 GHz，FBW 7.64 %），最大增益为 -22 dBi（λ 0 为导向波长）。投射天线在多层组织模型、男性人体头部体素模型、频率依赖性皮肤模型和肌肉模型中都具有良好的性能，在 ISM 波段中保持了最小 -20 dB 的回波损耗。使用频率依赖性皮肤模型对拟议天线进行了设备集成，结果非常适合 ISM 波段的生物医学应用。裸天线用于研究人体头皮的比吸收率（SAR）。输入功率为 1 W 时，1 g 和 10 g 组织的研究结果分别为 626.05 W/kg 和 84.4 W/kg，但输入功率最大限制为 2.55 mW（1 g 组织）和 23.56 mW（10 g 组织），以符合 IEEE SAR 准则。在仿皮凝胶和动物组织中对制造的天线质量进行了验证，结果与模拟结果十分吻合。
{"title":"An implantable ISM band antenna for biomedical application","authors":"Moumita Bose, Ashim Kumar Biswas, Abhishek Sarkhel, Aparna Kundu, Ujjal Chakraborty","doi":"10.1515/freq-2023-0207","DOIUrl":"https://doi.org/10.1515/freq-2023-0207","url":null,"abstract":"This article presents a compact implantable antenna for biomedical use in the ISM band (2.4–2.48 GHz). The antenna is designed with Roger RT/duroid 6010.2LM high permittivity substrate of thickness 0.25 mm, and feed with a 50 Ω co-axial feed. A hybrid-loop resonator slot structure and C & I-shaped slots in the radiating patch has enabled the antenna to work in the ISM band. Via less ground makes this design simple, easier to fabricate, and a suitable candidate for implantable application. The proposed antenna occupies a small volume of 0.0984 <jats:italic>λ</jats:italic> <jats:sub>0</jats:sub> × 0.082 <jats:italic>λ</jats:italic> <jats:sub>0</jats:sub> × 0.00468 <jats:italic>λ</jats:italic> <jats:sub>0</jats:sub> and retained 152 MHz bandwidth (2.4077–2.5599 GHz with FBW 7.64 %) with a maximum gain of −22 dBi where <jats:italic>λ</jats:italic> <jats:sub>0</jats:sub> is guided wavelength. The projected antenna has good performance in the multi-layer tissue model, male human head voxel model, frequency-dependent skin model, and in muscle phantom by maintaining a minimum −20 dB return-loss in the ISM band. The proposed antenna’s Device Integration using a frequency-dependent skin phantom was performed and the results are well-suited for biomedical applications in the ISM band. The bare antenna was used to study the Specific Absorption Rate (SAR) in the human scalp. Where for 1 g and 10 g tissues the investigated results are 626.05 W/kg and 84.4 W/kg for an input power of 1 W, however the input power is limited to maximum 2.55 mW (for 1 g tissue) and 23.56 mW (for 10 g tissue) to comply with IEEE SAR guidelines. The qualities of the manufactured antenna are verified in a skin-imitating gel and animal tissue that exhibits good agreement with the simulation outcomes.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"41 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138826977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this article, an angle independent Metamaterial Microwave Absorbers (MMA) is designed and demonstrated. The design consists of two concentric hexagon connected through consolidated resistors. The absorber is imprinted on a metal-backed low cost FR4 dielectric substrate with a thickness of 3.2 mm (λ/0.07) and a dielectric constant of 4.3. The proposed structure exhibits a wide absorption bandwidth ranging from 2.8 to 10.42 GHz with absorptivity above 90 % covering S, C and X Band. In the area of interest, the current and electric field distribution has been examined, for two maximum peaks at a frequency of 3.66 and 9.54 GHz, with maximum absorptivity of 99.99 % and 99.44 % respectively. The presented absorber is examined under different polarization angles for phi and theta variation. The fabricated sheet consists of an array of a unit cell, which is examined inside the anechoic chamber with the help of two horn antennas and VNA. The tested and simulated results are compared and it was found that they are almost similar to each other with little variation due to fabrication tolerance. The presented absorber can be practically used for defence applications for Radar Cross Sections (RCS) reduction.
{"title":"Wide angle metamaterial absorber for S, C and X band application","authors":"Pavan Kumar Shukla, Neelesh Kumar Gupta, Achyutanand Mishra, Sharmila, Apranjal Singh, Chetan Barde","doi":"10.1515/freq-2022-0283","DOIUrl":"https://doi.org/10.1515/freq-2022-0283","url":null,"abstract":"Abstract In this article, an angle independent Metamaterial Microwave Absorbers (MMA) is designed and demonstrated. The design consists of two concentric hexagon connected through consolidated resistors. The absorber is imprinted on a metal-backed low cost FR4 dielectric substrate with a thickness of 3.2 mm (λ/0.07) and a dielectric constant of 4.3. The proposed structure exhibits a wide absorption bandwidth ranging from 2.8 to 10.42 GHz with absorptivity above 90 % covering S, C and X Band. In the area of interest, the current and electric field distribution has been examined, for two maximum peaks at a frequency of 3.66 and 9.54 GHz, with maximum absorptivity of 99.99 % and 99.44 % respectively. The presented absorber is examined under different polarization angles for phi and theta variation. The fabricated sheet consists of an array of a unit cell, which is examined inside the anechoic chamber with the help of two horn antennas and VNA. The tested and simulated results are compared and it was found that they are almost similar to each other with little variation due to fabrication tolerance. The presented absorber can be practically used for defence applications for Radar Cross Sections (RCS) reduction.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"58 35","pages":"21 - 29"},"PeriodicalIF":1.1,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139239962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, the design of broadband, wide-angle, direction-independent metamaterial (MM) electromagnetic wave (EM) absorber for K-band frequency application is investigated and validated experimentally. The unit cell of the metamaterial absorber consists of four 90° rotated L-shaped metallic patches imprinted on a dielectric substrate backed by a metallic sheet. The structure yield absorption in the broad frequency ranges from 22.5 to 29.3 GHz for both TE and TM polarized waves with more than 90 % absorptivity having a wide fractional bandwidth of (6.8 GHz) 25.8 %. The structure is four-fold symmetric and hence yields polarization insensitivity for different angles of polarization under both TE and TM polarized waves. The structure is also investigated under oblique incidence where the 80 % absorptivity holds up to 45° incident angles for both TE and TM waves. The absorption mechanism is explained with the help of top and bottom surface current distribution, induced electric field, and parametric analysis. To verify the resonance in the structure, characteristic mode, and equivalent circuit analysis have been carried out and presented. A prototype of the absorber has been fabricated and simulated results are validated with measured results. Measured results are showing good agreement with the simulated responses. The novelty of the proposed absorber lies in its unique metallic pattern on a λ0/8 (concerning the canter frequency of absorption bandwidth) thin FR-4 substrate while showing the wide absorption bandwidth and direction independence to normal and oblique incidence. The compact nature of the absorber and broadband response with good polarization insensitivity at normal and oblique incidence makes it commercially suitable for the reduction of radar cross section (RCS) in stealth applications at the K-band.
{"title":"Direction independent broad-band wide angle metamaterial absorber for “K” band applications","authors":"Laxmikant Dewangan, Megh Sainadh Patinavalasa, Juin Acharjee, Shrey Anant Sandiman, Saptarshi Ghosh, Nipun Kumar Mishra","doi":"10.1515/freq-2023-0151","DOIUrl":"https://doi.org/10.1515/freq-2023-0151","url":null,"abstract":"In this work, the design of broadband, wide-angle, direction-independent metamaterial (MM) electromagnetic wave (EM) absorber for K-band frequency application is investigated and validated experimentally. The unit cell of the metamaterial absorber consists of four 90° rotated L-shaped metallic patches imprinted on a dielectric substrate backed by a metallic sheet. The structure yield absorption in the broad frequency ranges from 22.5 to 29.3 GHz for both TE and TM polarized waves with more than 90 % absorptivity having a wide fractional bandwidth of (6.8 GHz) 25.8 %. The structure is four-fold symmetric and hence yields polarization insensitivity for different angles of polarization under both TE and TM polarized waves. The structure is also investigated under oblique incidence where the 80 % absorptivity holds up to 45° incident angles for both TE and TM waves. The absorption mechanism is explained with the help of top and bottom surface current distribution, induced electric field, and parametric analysis. To verify the resonance in the structure, characteristic mode, and equivalent circuit analysis have been carried out and presented. A prototype of the absorber has been fabricated and simulated results are validated with measured results. Measured results are showing good agreement with the simulated responses. The novelty of the proposed absorber lies in its unique metallic pattern on a <jats:italic>λ</jats:italic> <jats:sub>0</jats:sub>/8 (concerning the canter frequency of absorption bandwidth) thin FR-4 substrate while showing the wide absorption bandwidth and direction independence to normal and oblique incidence. The compact nature of the absorber and broadband response with good polarization insensitivity at normal and oblique incidence makes it commercially suitable for the reduction of radar cross section (RCS) in stealth applications at the K-band.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"13 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138520155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we introduce a novel design for a high-gain, low-profile quad-feed folded transmitarray antenna (FTA) to enable a more compact system. The proposed antenna system consists of a transmitarray, a reflectarray, and four identical planar microstrip U-slot patch antennas placed on the same surface of the reflectarray with an adjacent distance greater than 1λ. To compare the effectiveness of our design, we developed three different antenna array systems with the same aperture size: a single-feed transmitarray antenna (TA) system, the proposed quad-feed FTA system, and a single-feed FTA system. Our experimental results demonstrate that employing four symmetrical feeders with an adjacent distance of 3.2λ effectively reduces the height by about 76.7 % in comparison to the height of a single-feed TA, and by 30 % when compared to the height of a single-feed FTA. We also present the design, fabrication, and testing of a prototype of the proposed quad-feed FTA operating in the Ku-band. The measured results of the prototype confirm the effectiveness of our design.
{"title":"Profile reduction of folded transmitarray antenna using multiple feeders","authors":"Guowei Li, Yuehe Ge, Zhizhang (David) Chen","doi":"10.1515/freq-2023-0174","DOIUrl":"https://doi.org/10.1515/freq-2023-0174","url":null,"abstract":"In this paper, we introduce a novel design for a high-gain, low-profile quad-feed folded transmitarray antenna (FTA) to enable a more compact system. The proposed antenna system consists of a transmitarray, a reflectarray, and four identical planar microstrip U-slot patch antennas placed on the same surface of the reflectarray with an adjacent distance greater than 1<jats:italic>λ</jats:italic>. To compare the effectiveness of our design, we developed three different antenna array systems with the same aperture size: a single-feed transmitarray antenna (TA) system, the proposed quad-feed FTA system, and a single-feed FTA system. Our experimental results demonstrate that employing four symmetrical feeders with an adjacent distance of 3.2<jats:italic>λ</jats:italic> effectively reduces the height by about 76.7 % in comparison to the height of a single-feed TA, and by 30 % when compared to the height of a single-feed FTA. We also present the design, fabrication, and testing of a prototype of the proposed quad-feed FTA operating in the Ku-band. The measured results of the prototype confirm the effectiveness of our design.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"36 7","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138520166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amit D. Magdum, Harisha Shimoga Beerappa, Mallikarjun Erramshetty
Abstract The distorted Born iterative method (DBIM) is a popular quantitative reconstruction algorithm for solving electromagnetic inverse scattering problems. These problems are non-linear and ill-posed. As a result, the efficiency of the method is limited by local minima. To overcome this, a correct initial guess solution is needed to obtain a satisfactory result. The U-Net based Convolutional Neural Network (CNN) is used in this study to make a good initial guess for the DBIM technique. The permittivity estimate produced at the output of U-Net is then refined using an existing iterative optimization process. This method’s findings are compared with the conventional DBIM approach. Strong scattering profiles of synthetic and experimental datasets with homogeneous and heterogeneous scatterers are investigated to validate the efficiency of the proposed technique. The results suggest that the use of the deep learning technique for an initial guess of DBIM improves accuracy and convergence rate significantly.
{"title":"Deep learning based distorted Born iterative method for improving microwave imaging","authors":"Amit D. Magdum, Harisha Shimoga Beerappa, Mallikarjun Erramshetty","doi":"10.1515/freq-2023-0074","DOIUrl":"https://doi.org/10.1515/freq-2023-0074","url":null,"abstract":"Abstract The distorted Born iterative method (DBIM) is a popular quantitative reconstruction algorithm for solving electromagnetic inverse scattering problems. These problems are non-linear and ill-posed. As a result, the efficiency of the method is limited by local minima. To overcome this, a correct initial guess solution is needed to obtain a satisfactory result. The U-Net based Convolutional Neural Network (CNN) is used in this study to make a good initial guess for the DBIM technique. The permittivity estimate produced at the output of U-Net is then refined using an existing iterative optimization process. This method’s findings are compared with the conventional DBIM approach. Strong scattering profiles of synthetic and experimental datasets with homogeneous and heterogeneous scatterers are investigated to validate the efficiency of the proposed technique. The results suggest that the use of the deep learning technique for an initial guess of DBIM improves accuracy and convergence rate significantly.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"145 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135777397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The terahertz (THz) technology has fascinated lot of attention due to its enormous potential for a wide range of applications in the public, private and enterprise domains. This research work demonstrates the design structure and analysis of graphene based waveguide fed hybrid plasmonic THz patch antenna (HPTPA) constructed at around 3 THz. Hybrid plasmonic THz waveguide (HPTW) as a feeding line for the proposed THz patch antenna can increases antenna efficiency. The graphene is sandwiched between gallium arsenide (GaAs) and silver (Ag) to confine THz waves efficiently. Using mode analysis in finite element method for the proposed HPTW the propagation length, effective refractive index has been thoroughly examined. Based on the finite element method (FEM) approach, the results of the designed graphene-based waveguide fed HPTPA shows a high effective refractive index of 2.9, large propagation length of 230 µm, gain of 2.29 dBi, bandwidth of 200 GHz and efficiency of 85 % has obtained. The proposed graphene-based waveguide fed HPTPA could be beneficial to enable several photonic integrated circuit applications in next-generation wireless communication.
{"title":"Graphene based waveguide fed hybrid plasmonic terahertz patch antenna","authors":"Pallavi Mahankali, Shyamal Mondal, Rama Rao Thipparaju, Susila Mohandoss","doi":"10.1515/freq-2023-0070","DOIUrl":"https://doi.org/10.1515/freq-2023-0070","url":null,"abstract":"Abstract The terahertz (THz) technology has fascinated lot of attention due to its enormous potential for a wide range of applications in the public, private and enterprise domains. This research work demonstrates the design structure and analysis of graphene based waveguide fed hybrid plasmonic THz patch antenna (HPTPA) constructed at around 3 THz. Hybrid plasmonic THz waveguide (HPTW) as a feeding line for the proposed THz patch antenna can increases antenna efficiency. The graphene is sandwiched between gallium arsenide (GaAs) and silver (Ag) to confine THz waves efficiently. Using mode analysis in finite element method for the proposed HPTW the propagation length, effective refractive index has been thoroughly examined. Based on the finite element method (FEM) approach, the results of the designed graphene-based waveguide fed HPTPA shows a high effective refractive index of 2.9, large propagation length of 230 µm, gain of 2.29 dBi, bandwidth of 200 GHz and efficiency of 85 % has obtained. The proposed graphene-based waveguide fed HPTPA could be beneficial to enable several photonic integrated circuit applications in next-generation wireless communication.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"123 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135863373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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