International Journal of Microwave and Wireless Technologies最新文献

{"title":"Frequency reconfigurable circular microstrip G-slotted antenna with DGS for various wireless applications","authors":"Mamta, Vandana Nath","doi":"10.1017/s1759078724000242","DOIUrl":"https://doi.org/10.1017/s1759078724000242","url":null,"abstract":"<p>A novel reconfigurable circular microstrip G-slotted antenna having a circularly defected ground structure (DGS) capable of switching its resonance frequency for several microwave applications is presented in this paper. Reconfigurability of the proposed G-slot antenna is obtained by incorporating three PIN diodes. One diode is embedded in the patch and two diodes are integrated into the DGS structure at appropriate places in the slot to achieve four different wireless applications such as aeronautical radio navigation (4.3 GHz with gain 3.6 dB), satellite communication (3.78 GHz with gain 3.7 dB), mobile communication (4.55 GHz with gain 4.0 dB), and WiMAX (3.35 GHz with gain 3.3 dB). These four bands are achieved depending on the different biasing conditions of the three PIN switches used. Antenna performance has been analyzed in ANSYS Electronics Desktop 2018.2 software. The equivalent circuit component of the switching element (PIN diode) has been considered and designed during the simulation. The creative structure lies in the way that it exhibits higher gain with compact size than the previously reported similar antenna. A prototype of the proposed patch antenna has been fabricated on a Roger substrate and its testing and measurement have been performed to demonstrate its desirable characteristics and features.</p>","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"3 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140025430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The conceptual design of the high-efficiency 400 kW solid-state power station at 352 MHz for the European spallation source","authors":"Seyed Alireza Mohadeskasaei, Dragos Dancila","doi":"10.1017/s1759078724000175","DOIUrl":"https://doi.org/10.1017/s1759078724000175","url":null,"abstract":"<p>This paper introduces an innovative conceptual design of a 400 kW solid-state power amplifier (SSPA) station and presents preliminary measurements for the key components. Recent advancements and benefits of solid-state technology have made the prospect of replacing vacuum tubes increasingly appealing. Historically, a significant challenge was the limited output power capacity of individual solid-state transistors, necessitating the integration of numerous units to generate high-power microwave signals in the range of hundreds of kilowatts. However, modern transistors capable of producing over 2 kW of output power have emerged, facilitating this transition. Another weak point was low power efficiency in high-power operating mode. The advanced rugged technology (ART) of solid-state devices enables the utilization of these transistors in nonlinear and switching operating classes, thereby enabling the creation of high-efficiency high-power amplifiers. In this conceptual design, 264 SSPA modules based on ART, each with a power output of 1.6 kW, are combined. The measurements revealed a single SSPA capable of delivering up to 2 kW output power with a power efficiency of 73% at frequency of 352 MHz. Due to the minimal losses during module combination and working SSPA in Class-C operation mode, the power efficiency of the station is expected to closely mirror that of a single module.</p>","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"79 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An advanced solid-state RF power source maximizing energy efficiency for optimal superconducting RF cavity charging","authors":"Long Hoang Duc, Dragos Dancila","doi":"10.1017/s1759078724000205","DOIUrl":"https://doi.org/10.1017/s1759078724000205","url":null,"abstract":"This paper outlines an experimental demonstration of an envelope tracking (ET) technique applied to a kilowatt-level single-ended solid-state power amplifier (SSPA), aimed at enhancing the charging efficiency of superconducting radio frequency (SRF) cavities by reducing reflection power while maintaining a high degree of efficiency. The technique is particularly designed for the pulsed operation of the European Spallation Source (ESS) at a nominal frequency of 352 MHz, with a 5% duty cycle and a pulse width of 3.5 ms. The study introduces an optimal charging scheme using a solid-state-based amplifier to maintain high efficiency, allowing for power ramp-up while minimizing reflections from SRF cavities and optimizing SSPA efficiency. A fast envelope tracking power supply (ETPS) system is implemented for the approximately 300 ms charging time required by the SRF cavities at ESS. The ETPS system, demonstrated on a single module as a proof-of-concept with scalability potential to a 400 kW power station, indicates an overall average efficiency of 70% and a 24% energy saving over traditional vacuum-tube based amplifiers. This demonstrates the ET technique’s effectiveness at the kilowatt level for efficient SRF cavity charging with reduced reflection, offering significant efficiency and energy savings.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"41 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Overcoming the relative bandwidth limitations of single VCO frequency synthesizers by implementing a novel PLL architecture","authors":"Tobias T. Braun, Jan Schoepfel, Aldo J. Marquez M., Nils Pohl","doi":"10.1017/s1759078723001484","DOIUrl":"https://doi.org/10.1017/s1759078723001484","url":null,"abstract":"Frequency-modulated continuous-wave radar systems profit from increasing the absolute bandwidths of the generated frequency chirps to improve range resolution. As the relative bandwidth of SiGe-voltage-controlled oscillators (VCOs) is limited to about 80%, increasing the center frequency fundamentally or via frequency multiplication is the most direct way to increase that absolute bandwidth. However, as some applications require penetration depth, which dramatically decreases with frequency, other solutions are necessary. Therefore, state-of-the-art concepts rely on the down-conversion of generated frequency chirps via two separately stabilized frequency sources. This article implements a novel architecture, offering relative bandwidths of &gt;100% within a single phase-locked loop (PLL). Therefore, two VCOs at different center frequencies are fed into a down-conversion mixer, whose output is directly stabilized via that PLL with one loop filter generating both tuning voltages. Those circuit blocks can be summarized as one equivalent VCO, offering a higher relative bandwidth and a significantly more linear tuning curve. Thereby, a solution to limited relative bandwidths with high VCO gain variation of single VCO synthesizers is offered while substantially reducing the hardware and implementation effort compared to the state-of-the-art.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"126 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139954397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wideband millimeter-wave reflectarray antenna with reduced cross-polarization","authors":"Vidhyashree Sathyanarayanan, Gulam Nabi Alsath Mohammed, Kirubaveni Savarimuthu, Malathi Kanagasabai","doi":"10.1017/s1759078723001587","DOIUrl":"https://doi.org/10.1017/s1759078723001587","url":null,"abstract":"A novel wideband reflectarray antenna (RA) is designed for 5G millimeter (mm) wave communications in the frequency range of 26.5–36 GHz. The proposed unit cell is constructed using a grid periodicity of 0.52<jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" mimetype=\"image\" xlink:href=\"S1759078723001587_inline1.png\" /> <jats:tex-math>${{lambda }_0}{ }$</jats:tex-math> </jats:alternatives> </jats:inline-formula> that offers 636° phase change through phase delay lines (PDLs) (<jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" mimetype=\"image\" xlink:href=\"S1759078723001587_inline2.png\" /> <jats:tex-math>${{theta }_{text{s}}}$</jats:tex-math> </jats:alternatives> </jats:inline-formula>). These PDLs are attached to the outer end of the unit cell comprising semi-circular rings. Bandwidth enhancement is achieved by incorporating a corrugated slot technique and a suitable air gap beneath the substrate. The proposed center-fed reflectarray is composed of 513 elements distributed in a circular aperture (13.46<jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" mimetype=\"image\" xlink:href=\"S1759078723001587_inline3.png\" /> <jats:tex-math>${{lambda }_0}$</jats:tex-math> </jats:alternatives> </jats:inline-formula>). Using mirror-symmetrical distribution of the unit cells, a cross-polarization reduction as low as −50 dB is realized. At 30 GHz, RA has a measured peak gain of 28.2 dBi, a sidelobe level of −14.3 dB, and an aperture efficiency of 31.4%. The prototype antenna is fabricated, and the simulation results are experimentally validated. The measured 1-dB and 3-dB gain bandwidths of the proposed reflectarray antenna are 31.3% and 41.6%, respectively. The proposed broadband reflectarray can be a potential choice for inter-satellite services like inter-satellite networking/satellite positioning and control; fixed satellite services such as GPS satellite synchronization and data direct to home TV; and satellite position fixing.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"25 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139753909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Learning-based surface deformation recovery for large radio telescope antennas","authors":"Zhan Tong, Xuesong Ren, Guoxiang Meng","doi":"10.1017/s1759078724000217","DOIUrl":"https://doi.org/10.1017/s1759078724000217","url":null,"abstract":"The surface deformation of the main reflector in a large radio telescope is closely related to its working efficiency, which is important for some astronomical science studies. Here, we present a deep learning-based surface deformation recovery framework using non-interferometric intensity measurements as input. The recurrent convolutional neural network (RCNN) is developed to establish the inverse mapping relationship between the surface deformation of the main reflector and the intensity images at the aperture plane and at a near-field plane. Meanwhile, a physical forward propagation model is adopted to generate a large amount of data for pre-training in a computationally efficient manner. Then, the inverse mapping relationship is adjusted and improved by transfer learning using experimental data, which achieves a 15-fold reduction in the number of training image sets required, which is helpful to facilitate the practical application of deep learning in this field. In addition, the RCNN model can be trained as a denoiser, and it is robust to the axial positioning error of the measuring points. It is also promising to extend this method to the study of adaptive optics.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"5 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139753405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A wideband, thin, dual-negative, and polarization-independent square-tooth circular ring resonator-based metamaterial absorber for Ku-band applications","authors":"Ramesh Amugothu, Vakula Damera","doi":"10.1017/s1759078724000230","DOIUrl":"https://doi.org/10.1017/s1759078724000230","url":null,"abstract":"In the proposed paper, a novel design and realization of a wide-band, oblique angle-insensitive metamaterial absorbers are presented. The absorber is designed to work over a wide range of frequencies, making it suitable for Ku-band applications. To get wide band absorption, a novel SM-shaped design with a square-tooth circular ring resonator structure is designed efficiently. The unit cell structure is designed with a dielectric substrate (FR4) with a thickness of 3.2 mm (0.16<jats:italic>λ</jats:italic><jats:sub>0</jats:sub>), where <jats:italic>λ</jats:italic><jats:sub>0</jats:sub> is the wavelength of free space. The novel design of this configuration leads to wideband absorption with respect to a conventional absorber. Several physical parameters are also investigated, such as the dielectric constant, permittivity, permeability, impedance, and negative refractive index. The simulation and experimental results show from 13.60 to 16.14 GHz with 99.1% absorption, which is excellent agreement. The analysis of the proposed design indicates that it possesses the remarkable feature of being insensitive to polarization while also exhibiting high absorption even when the angle of incidence varies. For both the simulation and experiment, results are consistent with a frequency range of 13.60–16.14 GHz for normal incidence. Almost perfect absorption works well for solar cells, EM detection, and imaging applications.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"26 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139753913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of dual-band tunable bandpass filter with constant absolute bandwidth based on triple transmission path","authors":"Jing Guo, Lirong Qian, Litian Wang, Cuiping Li, Yahui Tian, Honglang Li","doi":"10.1017/s1759078724000138","DOIUrl":"https://doi.org/10.1017/s1759078724000138","url":null,"abstract":"In this paper, a novel tunable dual-band bandpass filter (BPF) with independently controlled passbands and constant absolute bandwidth (CABW) is proposed. The CABW passbands of designed dual-band BPF are obtained using manageable electric and magnetic mix coupling. Furthermore, the multiple transmission paths from the input port to the output port are extended for extra transmission zeros, which results in modified selectivity of the proposed dual-band BPF. The tunability and switchability of the developed filter can be implemented by introducing a single bias voltage of varactors for each band. For the tunable dual-band BPF, the simulated results show that the center frequency (CF) of the first passband varies from 2.38 to 2.68 GHz, and the CF of the second passband varies from 3.28 to 3.88 GHz, while 3-dB absolute bandwidths are 101 ± 7 MHz and 98 ± 4 MHz, respectively. Moreover, the two passbands of the filter can also be independently switched by removing the voltage imposed on the varactor C<jats:sub>V1</jats:sub> and C<jats:sub>V2</jats:sub>. The measured results agree well with simulated results, which verify the design theory.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"13 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139753830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wideband filtering power amplifier based on terminated coupled line structure","authors":"Guohua Liu, Jianyuan Yu, Yijun Lin","doi":"10.1017/s1759078724000059","DOIUrl":"https://doi.org/10.1017/s1759078724000059","url":null,"abstract":"This paper proposes a design method for designing a wideband filtering power amplifier (PA) based on terminated coupled line structure (TCLS). This method generates four transmission zeros and three transmission poles by loading stepped impedance resonator and short-circuit stubs on the four ports of TCLS, which greatly optimizes the in-band return loss and stopband suppression of the output matching network. In addition, the effective suppression of the second harmonic also increases the efficiency of the PA. In order to verify the effectiveness and superiority of this design method, a wideband bandpass filtering PA is designed and manufactured in 2.9–3.7 GHz. Measurement results show that the saturated output power is from 40.1 dBm to 41.2 dBm, the drain efficiency is greater than 60.3%, and the gain is 10–11.2 dB.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"223 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139753627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An enhanced wideband tracking method for characteristic modes","authors":"Chao Huang, Chenjiang Guo, Xia Ma, Yi Yuan, Jun Ding","doi":"10.1017/s1759078724000229","DOIUrl":"https://doi.org/10.1017/s1759078724000229","url":null,"abstract":"An enhanced wideband tracking method for characteristic modes (CMs) is investigated in this paper. The method consists of three stages, and its core tracking stage (CTS) is based on a classical eigenvector correlation-based algorithm. To decrease the tracking time and eliminate the crossing avoidance (CRA), we append a commonly used eigenvalue filter (EF) as the preprocessing stage and a novel postprocessing stage to the CTS. The proposed postprocessing stage can identify all CRA mode pairs by analyzing their trajectory and correlation characteristics. Subsequently, it can predict corresponding CRA frequencies and correct problematic qualities rapidly. Considering potential variations in eigenvector numbers at consecutive frequency samples caused by the EF, a new execution condition for the adaptive frequency adjustment in the CTS is introduced. Finally, CMs of a conductor plate and a fractal structure are investigated to demonstrate the performance of the proposed method, and the obtained results are discussed.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":"254 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139753673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}