Liquid crystal microwave phased arrays (LC-MPAs) are regarded as an ideal approach to realize compact antennas owing to their advantages in cost, size, weight, and power consumption. However, the shortcoming in low radiation deflection efficiency has been one of LC-MPAs’ main application limitations. To optimize the steering performance of LC-MPAs, it is essential to model the channel imperfections and compensate for the phase errors. In this paper, a phase error estimation model is built by training a neural network to establish a nonlinear relationship between the near-field phase error and the far-field pattern, hence realizing fast calibration for LC-MPAs within several measured patterns. Simulations and experiments on a 64-channel, two-dimensional planar antenna were conducted to validate this method. The results show that this method offers precise phase error estimations of 3.58° on average, realizes a fast calibration process with several field-measured radiation patterns, and improves the performances of the LC-MPA by approximately 4%–10% in deflection efficiency at different steering angles.
{"title":"A fast phase calibration method for a liquid crystal microwave phased array antenna assisted by neural network","authors":"Qianying Yan, Yanwei Huang, Wenzhao Zhang, Xin Hou, Mengqing Zhang, Xiangru Wang, Feng Liang","doi":"10.1017/s175907872400014x","DOIUrl":"https://doi.org/10.1017/s175907872400014x","url":null,"abstract":"Liquid crystal microwave phased arrays (LC-MPAs) are regarded as an ideal approach to realize compact antennas owing to their advantages in cost, size, weight, and power consumption. However, the shortcoming in low radiation deflection efficiency has been one of LC-MPAs’ main application limitations. To optimize the steering performance of LC-MPAs, it is essential to model the channel imperfections and compensate for the phase errors. In this paper, a phase error estimation model is built by training a neural network to establish a nonlinear relationship between the near-field phase error and the far-field pattern, hence realizing fast calibration for LC-MPAs within several measured patterns. Simulations and experiments on a 64-channel, two-dimensional planar antenna were conducted to validate this method. The results show that this method offers precise phase error estimations of 3.58° on average, realizes a fast calibration process with several field-measured radiation patterns, and improves the performances of the LC-MPA by approximately 4%–10% in deflection efficiency at different steering angles.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209955","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}
Pub Date : 2024-07-02DOI: 10.1017/s1759078724000084
Yunlong Li, Changjun Tian, Shaozhuo Li, Peng Chen, Yun Li, Kai Yang
This paper proposes an air-filled substrate integrated waveguide (AFSIW) bandpass filter with a miniaturized non-resonant node (NRN). The NRN structure is introduced between the three resonators, and its size is smaller than the resonator size, which can realize the NRN structure’s miniaturization and reduce the model’s size. The NRN size of this filter is 41% of the NRN size of the existing AFSIW filter. This filter also introduces a transmission zero (TZ) above the passband. The measured results show that the filter’s center frequency is 20.73 GHz, and the bandwidth is 0.86 GHz. The insertion loss in the passband is 0.95 dB, and the return loss is better than 23 dB. Due to the TZ in the upper stopband, the AFSIW filter obtained good selectivity.
{"title":"Air-filled substrate integrated waveguide bandpass filter based on miniaturized non-resonant node structure","authors":"Yunlong Li, Changjun Tian, Shaozhuo Li, Peng Chen, Yun Li, Kai Yang","doi":"10.1017/s1759078724000084","DOIUrl":"https://doi.org/10.1017/s1759078724000084","url":null,"abstract":"This paper proposes an air-filled substrate integrated waveguide (AFSIW) bandpass filter with a miniaturized non-resonant node (NRN). The NRN structure is introduced between the three resonators, and its size is smaller than the resonator size, which can realize the NRN structure’s miniaturization and reduce the model’s size. The NRN size of this filter is 41% of the NRN size of the existing AFSIW filter. This filter also introduces a transmission zero (TZ) above the passband. The measured results show that the filter’s center frequency is 20.73 GHz, and the bandwidth is 0.86 GHz. The insertion loss in the passband is 0.95 dB, and the return loss is better than 23 dB. Due to the TZ in the upper stopband, the AFSIW filter obtained good selectivity.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504824","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}
Pub Date : 2024-07-02DOI: 10.1017/s1759078724000606
Luyu Zhang, Zhiwei Zhang, Chenlu Wang, Chao Gu
This paper presents a design methodology for a broadband high-efficiency power amplifier (PA). The large available impedance space of the extended continuous Class-GF mode is employed. A novel output matching network of the PA consisting of a rectangular double transmission line structure is proposed to meet impedance requirements. To validate the effectiveness of this structure, a high-efficiency PA operating in 0.8–3.0 GHz is designed using a CGH40010F GaN transistor. The measured results demonstrate that the drain efficiency falls within the range of 63.2%–71.9%, the output power varies from 40.2 to 42.2 dBm, and the gain ranges from 9.4 to 11.3 dB within the frequency band of 0.8–3 GHz. The realized PA exhibits an extremely competitive relative bandwidth of 115.8%.
{"title":"Design of a broadband high-efficiency power amplifier based on a rectangular double transmission line structure","authors":"Luyu Zhang, Zhiwei Zhang, Chenlu Wang, Chao Gu","doi":"10.1017/s1759078724000606","DOIUrl":"https://doi.org/10.1017/s1759078724000606","url":null,"abstract":"This paper presents a design methodology for a broadband high-efficiency power amplifier (PA). The large available impedance space of the extended continuous Class-GF mode is employed. A novel output matching network of the PA consisting of a rectangular double transmission line structure is proposed to meet impedance requirements. To validate the effectiveness of this structure, a high-efficiency PA operating in 0.8–3.0 GHz is designed using a CGH40010F GaN transistor. The measured results demonstrate that the drain efficiency falls within the range of 63.2%–71.9%, the output power varies from 40.2 to 42.2 dBm, and the gain ranges from 9.4 to 11.3 dB within the frequency band of 0.8–3 GHz. The realized PA exhibits an extremely competitive relative bandwidth of 115.8%.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529085","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}
Pub Date : 2024-05-30DOI: 10.1017/s1759078724000539
Sen Xu, JianFeng Wu, Xiang Chen
A systematic design approach is presented for the design of broadband high-efficiency power amplifiers (PAs) by combining an improved ring-resonant filter matching network with a series of continuous modes. The improved ring-resonant matching network presented can effectively enhance out-of-band attenuation and sharp roll-off characteristics by adding a compensation structure with parallel stub. To verify the proposed design theory, a 10-W GaN HEMT device is designed and fabricated. The test results indicate that from the operating frequency band of 0.55−3.3 GHz with a relative bandwidth of 142.9%, a saturated output power of 38.5−42 dBm, drain efficiency of 58.2−70.3%, and a gain of 8.5–12 dB can be achieved under 3 dB gain compression, indicating the rationality of the design theory.
通过将改进的环形谐振滤波器匹配网络与一系列连续模式相结合，提出了一种设计宽带高效功率放大器（PA）的系统设计方法。所提出的改进型环形谐振匹配网络通过添加带有并联存根的补偿结构，可有效增强带外衰减和尖锐滚降特性。为了验证所提出的设计理论，我们设计并制造了一个 10 瓦的 GaN HEMT 器件。测试结果表明，在相对带宽为 142.9% 的 0.55-3.3 GHz 工作频段内，可实现 38.5-42 dBm 的饱和输出功率、58.2-70.3% 的漏极效率以及 8.5-12 dB 的增益，增益压缩为 3 dB，这表明了设计理论的合理性。
{"title":"Design of a broadband high-efficiency power amplifier based on ring-resonant filter with compensation architecture and a series of continuous modes","authors":"Sen Xu, JianFeng Wu, Xiang Chen","doi":"10.1017/s1759078724000539","DOIUrl":"https://doi.org/10.1017/s1759078724000539","url":null,"abstract":"A systematic design approach is presented for the design of broadband high-efficiency power amplifiers (PAs) by combining an improved ring-resonant filter matching network with a series of continuous modes. The improved ring-resonant matching network presented can effectively enhance out-of-band attenuation and sharp roll-off characteristics by adding a compensation structure with parallel stub. To verify the proposed design theory, a 10-W GaN HEMT device is designed and fabricated. The test results indicate that from the operating frequency band of 0.55−3.3 GHz with a relative bandwidth of 142.9%, a saturated output power of 38.5−42 dBm, drain efficiency of 58.2−70.3%, and a gain of 8.5–12 dB can be achieved under 3 dB gain compression, indicating the rationality of the design theory.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141192482","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}
Pub Date : 2024-05-30DOI: 10.1017/s1759078724000588
Hui Pang, Jianping Zhao, Juan Xu
A multiresonance metasurface antenna is proposed which has wide bandwidth and low-profile. The characteristic mode theory is used to design antenna structure. Three ideal modes are obtained by adjusting the mode currents to optimize the radiation performance of the antenna. The characteristic mode analysis is used to model, analyze, and optimize the antenna, revealing the physical characteristics of the metasurface antenna. The slot is not only used as the feeding structure for exciting characteristic modes but also introduces a slot mode. Combining the slot mode with the metasurface modes, the bandwidth of the antenna is broadened. The antenna element has a relative bandwidth of 43.7%. To obtain higher gain, a 2 × 2 antenna array is proposed. The antenna array is simulated, fabricated, and measured. The results show that the relative bandwidth of the proposed metasurface antenna array is 31.6% with the gain of 12.3–15.8 dBi over the operating bandwidth.
{"title":"A broadband metasurface antenna with multimode resonance","authors":"Hui Pang, Jianping Zhao, Juan Xu","doi":"10.1017/s1759078724000588","DOIUrl":"https://doi.org/10.1017/s1759078724000588","url":null,"abstract":"A multiresonance metasurface antenna is proposed which has wide bandwidth and low-profile. The characteristic mode theory is used to design antenna structure. Three ideal modes are obtained by adjusting the mode currents to optimize the radiation performance of the antenna. The characteristic mode analysis is used to model, analyze, and optimize the antenna, revealing the physical characteristics of the metasurface antenna. The slot is not only used as the feeding structure for exciting characteristic modes but also introduces a slot mode. Combining the slot mode with the metasurface modes, the bandwidth of the antenna is broadened. The antenna element has a relative bandwidth of 43.7%. To obtain higher gain, a 2 × 2 antenna array is proposed. The antenna array is simulated, fabricated, and measured. The results show that the relative bandwidth of the proposed metasurface antenna array is 31.6% with the gain of 12.3–15.8 dBi over the operating bandwidth.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141192389","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}
This research article proposes a dual-sense dual-port wideband circularly polarized (CP) multi-input multi-output (MIMO) antenna designed for Wi-Fi 6E applications. The main novelty lies in achieving CP for both ports using a truncated rectangular-shaped aperture. By incorporating design and spatial diversity and defective ground structure between the two radiators, the design improves isolation and enables the antenna to generate Left-Hand Circular Polarization (LHCP)depending on the selected feed port. The proposed MIMO rectangular dielectric resonator antenna demonstrates an impressive impedance-matching bandwidth (IBW)from 5.5 to 8.0 GHz (37.10%) as well as an axial ratio bandwidth (ARBW) covering from 6.0 to 6.55 GHz (12.20%). Additionally, the dual-port wideband CP MIMO antenna exhibits satisfactory diversity performance parameters. To validate the simulated results, a physical prototype is fabricated and subjected to experimental testing. The measured outcomes of the fabricated model align closely with the simulated results, confirming the accuracy of the design. With both MIMO and CP capabilities and improved isolation, this proposed model proves beneficial in reducing latency and minimizing the impact of multipath fading. Therefore, it stands as an excellent choice for future devices utilizing the Wi-Fi 6E band due to its broad IBW and overlappingAR.
本文提出了一种双感应双端口宽带圆极化（CP）多输入多输出（MIMO）天线，设计用于 Wi-Fi 6E 应用。其主要创新点在于利用截断矩形孔径实现两个端口的 CP。通过在两个辐射器之间加入设计和空间分集以及有缺陷的接地结构，该设计提高了隔离度，并使天线能够根据所选的馈电端口产生左旋圆极化（LHCP）。所提出的 MIMO 矩形介质谐振器天线的阻抗匹配带宽（IBW）从 5.5 GHz 到 8.0 GHz（37.10%），轴向比带宽（ARBW）从 6.0 GHz 到 6.55 GHz（12.20%），令人印象深刻。此外，双端口宽带 CP MIMO 天线的分集性能参数也令人满意。为了验证模拟结果，我们制作了一个物理原型并进行了实验测试。制作模型的测量结果与模拟结果非常吻合，证实了设计的准确性。该模型具有 MIMO 和 CP 功能，并改进了隔离性能，因此在减少延迟和最大限度地降低多径衰落的影响方面大有裨益。因此，由于其宽广的 IBW 和重叠AR，它是未来使用 Wi-Fi 6E 频段的设备的绝佳选择。
{"title":"Circularly polarized dual-port MIMO DRA for future Wi-Fi 6E applications","authors":"Javed Iqbal, Usman Illahi, Shahid Mahmood Ramay, Mohamad Ismail Sulaiman","doi":"10.1017/s1759078724000576","DOIUrl":"https://doi.org/10.1017/s1759078724000576","url":null,"abstract":"This research article proposes a dual-sense dual-port wideband circularly polarized (CP) multi-input multi-output (MIMO) antenna designed for Wi-Fi 6E applications. The main novelty lies in achieving CP for both ports using a truncated rectangular-shaped aperture. By incorporating design and spatial diversity and defective ground structure between the two radiators, the design improves isolation and enables the antenna to generate Left-Hand Circular Polarization (LHCP)depending on the selected feed port. The proposed MIMO rectangular dielectric resonator antenna demonstrates an impressive impedance-matching bandwidth (IBW)from 5.5 to 8.0 GHz (37.10%) as well as an axial ratio bandwidth (ARBW) covering from 6.0 to 6.55 GHz (12.20%). Additionally, the dual-port wideband CP MIMO antenna exhibits satisfactory diversity performance parameters. To validate the simulated results, a physical prototype is fabricated and subjected to experimental testing. The measured outcomes of the fabricated model align closely with the simulated results, confirming the accuracy of the design. With both MIMO and CP capabilities and improved isolation, this proposed model proves beneficial in reducing latency and minimizing the impact of multipath fading. Therefore, it stands as an excellent choice for future devices utilizing the Wi-Fi 6E band due to its broad IBW and overlappingAR.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141198348","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}
Pub Date : 2024-05-30DOI: 10.1017/s1759078724000527
Davide Arenare, Fabio Pelorossi, Filippo Concaro, Marco Pasian
Large reflector antennas, such as the European Space Agency deep space antennas (DSAs), practically always require struts to support the sub-reflector. While inevitable, they deteriorate the antenna performance. To minimize this deterioration, it is pivotal to understand the role played by different features, including struts diameter and shape. This paper proposes a detailed numerical investigation on the impact of these features on antenna efficiency and side lobes, for a test case comprising both DSA3 and DSA4. It is demonstrated, for the first time in a comprehensive and quantitative way that includes different permutations for the strut design, that both features are significant to define the deterioration, thus providing a significant feedback for struts design.
{"title":"On the effects of struts diameter and shape on the European Space Agency deep space antenna directivity and first side lobe","authors":"Davide Arenare, Fabio Pelorossi, Filippo Concaro, Marco Pasian","doi":"10.1017/s1759078724000527","DOIUrl":"https://doi.org/10.1017/s1759078724000527","url":null,"abstract":"Large reflector antennas, such as the European Space Agency deep space antennas (DSAs), practically always require struts to support the sub-reflector. While inevitable, they deteriorate the antenna performance. To minimize this deterioration, it is pivotal to understand the role played by different features, including struts diameter and shape. This paper proposes a detailed numerical investigation on the impact of these features on antenna efficiency and side lobes, for a test case comprising both DSA3 and DSA4. It is demonstrated, for the first time in a comprehensive and quantitative way that includes different permutations for the strut design, that both features are significant to define the deterioration, thus providing a significant feedback for struts design.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141192500","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}
Pub Date : 2024-05-22DOI: 10.1017/s1759078724000370
Mamta Tikaria, Vineeta Saxena Nigam
Path loss prediction (PLP) is an important feature of wireless communications because it allows a receiver to anticipate the signal strength that will be received from a transmitter at a given distance. The PLP is done by using machine learning models that take into account numerous aspects such as the frequency of the signal, the surroundings, and the type of antenna. Various machine learning methods are used to anticipate path loss propagation but it is difficult to predict path loss in unknown propagation conditions. In existing models rely on incomplete or outdated data, which can affect the accuracy and reliability of predictions and they do not take into account the effects of environmental factors, such as terrain, foliage, and weather conditions, on path loss. Furthermore, existing models are not robust enough to handle the real-world variability and uncertainty, leading to significant errors in predictions. To tackle this issue, a novel ultrahigh frequency (UHF) PLP based on K-nearest neighbors (KNNs) is developed for predicting and optimizing the path loss for UHF. In this proposed model, a KNN-based PLP has been used to predict the path loss in the UHF. This technique is used for high-accuracy PLP through KNN forecast route loss by determining the K-nearest data points to a particular test point based on a distance metric. Moreover, the existing models were not able to optimize path loss due to complex and large-scale machine learning models. Therefore, the stochastic gradient descent technique has been used to minimize the objective function, which is often a measure of the difference between the model’s predictions and the actual output that will fine-tune the parameters of the KNN model, by measuring the similarity between data points. This model is implemented using Python to make it a lot more convenient.
路径损耗预测（PLP）是无线通信的一项重要功能，因为它允许接收器预测在给定距离内从发射器接收到的信号强度。路径损耗预测是通过使用机器学习模型来完成的，这些模型考虑了信号频率、周围环境和天线类型等多个方面。各种机器学习方法用于预测路径损耗传播，但很难预测未知传播条件下的路径损耗。现有模型依赖于不完整或过时的数据，这会影响预测的准确性和可靠性，而且这些模型没有考虑地形、树叶和天气条件等环境因素对路径损耗的影响。此外，现有模型的鲁棒性不足以处理现实世界中的可变性和不确定性，从而导致预测出现重大误差。为解决这一问题，我们开发了一种基于 K 近邻（KNN）的新型超高频（UHF）PLP，用于预测和优化超高频的路径损耗。在这一拟议模型中，基于 KNN 的 PLP 被用于预测超高频的路径损耗。该技术通过 KNN 预测路径损耗，根据距离度量确定距离特定测试点最近的 K 个数据点，从而实现高精度 PLP。此外，由于复杂的大规模机器学习模型，现有模型无法优化路径损耗。因此，我们采用了随机梯度下降技术，通过测量数据点之间的相似性来最小化目标函数，而目标函数通常是模型预测与实际输出之间差异的度量，它将微调 KNN 模型的参数。该模型使用 Python 实现，因此更加方便。
{"title":"Ultrahigh frequency path loss prediction based on K-nearest neighbors","authors":"Mamta Tikaria, Vineeta Saxena Nigam","doi":"10.1017/s1759078724000370","DOIUrl":"https://doi.org/10.1017/s1759078724000370","url":null,"abstract":"\u0000 Path loss prediction (PLP) is an important feature of wireless communications because it allows a receiver to anticipate the signal strength that will be received from a transmitter at a given distance. The PLP is done by using machine learning models that take into account numerous aspects such as the frequency of the signal, the surroundings, and the type of antenna. Various machine learning methods are used to anticipate path loss propagation but it is difficult to predict path loss in unknown propagation conditions. In existing models rely on incomplete or outdated data, which can affect the accuracy and reliability of predictions and they do not take into account the effects of environmental factors, such as terrain, foliage, and weather conditions, on path loss. Furthermore, existing models are not robust enough to handle the real-world variability and uncertainty, leading to significant errors in predictions. To tackle this issue, a novel ultrahigh frequency (UHF) PLP based on K-nearest neighbors (KNNs) is developed for predicting and optimizing the path loss for UHF. In this proposed model, a KNN-based PLP has been used to predict the path loss in the UHF. This technique is used for high-accuracy PLP through KNN forecast route loss by determining the K-nearest data points to a particular test point based on a distance metric. Moreover, the existing models were not able to optimize path loss due to complex and large-scale machine learning models. Therefore, the stochastic gradient descent technique has been used to minimize the objective function, which is often a measure of the difference between the model’s predictions and the actual output that will fine-tune the parameters of the KNN model, by measuring the similarity between data points. This model is implemented using Python to make it a lot more convenient.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141108877","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}
Pub Date : 2024-05-20DOI: 10.1017/s1759078723001538
E. Negri, F. Benassi, W. Fuscaldo, D. Masotti, P. Burghignoli, A. Costanzo, Alessandro Galli
Resonant Bessel-beam launchers (BBLs)are radiating devices constituted by a cylindrical metallic cavity with a partially reflecting sheet (PRS) on top. Millimeter-wave resonant BBLs typically exhibit transverse magnetic (TM) polarization due to the use of coaxial probes as feeders and homogenized metasurfaces as PRS. Launchers showing either a purely transverse electric (TE) or a hybrid (quasi-TE) polarization have recently been proposed for realizing wireless power transfer (WPT) links in the radiative near-field region at millimeter waves. The former are obtained by means of a radial slot array as a feeder and a homogenized metasurface as a PRS. The latter are obtained by using a loop antenna as a feeder and an annular strip grating in the homogenization limit as radiating aperture. In this work, based on an original semi-analytical model, such a metasurface is demonstrated to show a dichroic behavior. This interpretation explains the improvement in terms of polarization purity with respect to more nondichroic conventional homogenized metasurfaces. The behavior of the annular strip grating under a pure TM polarization is tested with a coaxial feeder, whereas its behavior under a pure TE polarization is tested by means of the radial slot array feeder. Results confirm the validity of the proposed analysis, which is finally exploited to evaluate the WPT performance.
{"title":"Design of TE-polarized resonant Bessel-beam launchers for wireless power transfer links in the radiative near-field region","authors":"E. Negri, F. Benassi, W. Fuscaldo, D. Masotti, P. Burghignoli, A. Costanzo, Alessandro Galli","doi":"10.1017/s1759078723001538","DOIUrl":"https://doi.org/10.1017/s1759078723001538","url":null,"abstract":"\u0000 Resonant Bessel-beam launchers (BBLs)are radiating devices constituted by a cylindrical metallic cavity with a partially reflecting sheet (PRS) on top. Millimeter-wave resonant BBLs typically exhibit transverse magnetic (TM) polarization due to the use of coaxial probes as feeders and homogenized metasurfaces as PRS. Launchers showing either a purely transverse electric (TE) or a hybrid (quasi-TE) polarization have recently been proposed for realizing wireless power transfer (WPT) links in the radiative near-field region at millimeter waves. The former are obtained by means of a radial slot array as a feeder and a homogenized metasurface as a PRS. The latter are obtained by using a loop antenna as a feeder and an annular strip grating in the homogenization limit as radiating aperture. In this work, based on an original semi-analytical model, such a metasurface is demonstrated to show a dichroic behavior. This interpretation explains the improvement in terms of polarization purity with respect to more nondichroic conventional homogenized metasurfaces. The behavior of the annular strip grating under a pure TM polarization is tested with a coaxial feeder, whereas its behavior under a pure TE polarization is tested by means of the radial slot array feeder. Results confirm the validity of the proposed analysis, which is finally exploited to evaluate the WPT performance.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141120673","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}
A bandwidth expansion strategy for ultra-wideband power amplifiers (PAs) is presented in this letter by adopting a parallel impedance matching architecture. This design strategy can effectively reduce the impedance conversion ratio between the load and the target impedance of the PA, thereby providing a feasible solution for broadband impedance matching. Subsequently, a commercially available 10 W gallium nitride device and a two-stage Wilkinson power divider network are combined to achieve the verification of the proposed theory. The results of the measurement show that within the target frequency band of 0.9–3.9 GHz, 58.5–71.2% of the drain efficiency and 9.1–12 dB of gain can be achieved with a saturated output power of 39.1–42 dBm.
本文通过采用并行阻抗匹配架构，提出了一种超宽带功率放大器（PA）的带宽扩展策略。这种设计策略可有效降低功率放大器负载与目标阻抗之间的阻抗转换率，从而为宽带阻抗匹配提供可行的解决方案。随后，结合市售的 10 W 氮化镓器件和两级威尔金森功率分压器网络，对所提出的理论进行了验证。测量结果表明，在 0.9-3.9 GHz 的目标频段内，可以实现 58.5-71.2% 的漏极效率和 9.1-12 dB 的增益，饱和输出功率为 39.1-42 dBm。
{"title":"An ultra-wideband power amplifier designed through a bandwidth expansion strategy","authors":"Xuefei Xuan, Zhiqun Cheng, Brendan Hayes, Zhiwei Zhang, Tingwei Gong, Shenbing Wu, Chao Le","doi":"10.1017/s1759078724000552","DOIUrl":"https://doi.org/10.1017/s1759078724000552","url":null,"abstract":"A bandwidth expansion strategy for ultra-wideband power amplifiers (PAs) is presented in this letter by adopting a parallel impedance matching architecture. This design strategy can effectively reduce the impedance conversion ratio between the load and the target impedance of the PA, thereby providing a feasible solution for broadband impedance matching. Subsequently, a commercially available 10 W gallium nitride device and a two-stage Wilkinson power divider network are combined to achieve the verification of the proposed theory. The results of the measurement show that within the target frequency band of 0.9–3.9 GHz, 58.5–71.2% of the drain efficiency and 9.1–12 dB of gain can be achieved with a saturated output power of 39.1–42 dBm.","PeriodicalId":49052,"journal":{"name":"International Journal of Microwave and Wireless Technologies","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140935670","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}
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