Frequenz最新文献_第9页

Dual-band open-loop monopole (2 × 1) printed MIMO antenna for 4G and 5G applications 用于4G和5G应用的双频开环单极子（2×1）印刷MIMO天线

IF 1.1 4区工程技术

Frequenz Pub Date : 2023-02-16 DOI: 10.1515/freq-2022-0141

A. Abdulhameed, F. Alnahwi, A. Abdullah

引用次数: 1

A novel non-iterative algorithm for the joint design of transceiver beamforming and surface reflection in an IRS-enhanced MIMO system IRS增强MIMO系统中收发器波束形成和表面反射联合设计的一种新的非迭代算法

IF 1.1 4区工程技术

Frequenz Pub Date : 2023-02-16 DOI: 10.1515/freq-2022-0189

S.M.J. Asgari Tabatabaee, Farid Samsami Khodadad

{"title":"A novel non-iterative algorithm for the joint design of transceiver beamforming and surface reflection in an IRS-enhanced MIMO system","authors":"S.M.J. Asgari Tabatabaee, Farid Samsami Khodadad","doi":"10.1515/freq-2022-0189","DOIUrl":"https://doi.org/10.1515/freq-2022-0189","url":null,"abstract":"Abstract Intelligent reflecting surface (IRS) is an emerging and low-cost revolutionary technology that can be deployed in future communication systems to enhance data transmission performance. An IRS comprises a lot of small, passive, and low-cost elements that can smartly reflect the incident signal from the transmitter to the receiver. In this paper, an IRS-enhanced multiple-input multiple-output (MIMO) downlink network is considered, in which a cell-edge user receives the data signal from a base station (BS). In this network, the direct path between the BS and the user is blocked by an obstacle, and the user receives only the tunable reflected signal from the IRS. To achieve spatial diversity, beamforming is applied to the antennas at the BS and the user. The goal is to jointly design the transceiver beamforming vectors and the IRS reflection coefficients so that the signal-to-noise ratio (SNR) of the user is maximized. Since the IRS elements are passive, the amplitude of the IRS reflection coefficients must be equal to or smaller than one. The constrained SNR optimization problem is non-convex. We propose a three-step procedure to obtain an effective sub-optimal solution for this problem. Accordingly, an innovative non-iterative algorithm is proposed to design the problem parameters. Simulation results show that the IRS-enhanced MIMO downlink system, in which the proposed non-iterative algorithm is used to develop the network parameters, outperforms the conventional network without IRS in terms of bit error rate (BER).","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"77 1","pages":"371 - 383"},"PeriodicalIF":1.1,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48728204","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}

引用次数: 0

Design of dual-band BPFs with high selectivity 高选择性双频带BPF的设计

IF 1.1 4区工程技术

Frequenz Pub Date : 2023-01-16 DOI: 10.1515/freq-2022-0178

Min Wang, Lei Chen, T. Zhang, Jiahui Peng

引用次数: 0

n-3 PUFA can reduce IL-6 and TNF levels in patients with cancer. n-3 PUFA可降低肿瘤患者IL-6和TNF水平

IF 3.6 4区工程技术

Frequenz Pub Date : 2023-01-14 Epub Date: 2022-03-07 DOI: 10.1017/S0007114522000575

Yongzhong Guo, Bo Ma, Xinhua Li, Hui Hui, Yun Zhou, Na Li, Xiaomei Xie

{"title":"n-3 PUFA can reduce IL-6 and TNF levels in patients with cancer.","authors":"Yongzhong Guo, Bo Ma, Xinhua Li, Hui Hui, Yun Zhou, Na Li, Xiaomei Xie","doi":"10.1017/S0007114522000575","DOIUrl":"10.1017/S0007114522000575","url":null,"abstract":"Current studies on inhibitory effects of n-3 PUFA on pro-inflammatory cytokines have inconsistent results. Thus, a meta-analysis of randomised controlled trials was conducted to identify the effects of n-3 PUFA administration on circulating IL-6 and TNF in patients with cancer. Studies that examined the effects of n-3 PUFA administration on circulating IL-6 and TNF in patients with cancer were identified by searching PubMed and EMBASE from January 1975 to February 2021. Differences in n-3 PUFA administration and control conditions were determined by calculating standardised mean differences (SMD) with 95 % CI. Twenty studies involving 971 patients met the inclusion criteria. The overall SMD were 0·485 (95 % CI 0·087, 0·883) for IL-6 and 0·712 (95 % CI 0·461, 0·962) for TNF between n-3 PUFA administration and control conditions. Sources of heterogeneity were not found through subgroup and meta-regression analyses. Publication bias was observed in TNF with a slight contribution to the effect size. n-3 PUFA can reduce circulating IL-6 and TNF levels in patients with cancer. Results supported the recommendation of n-3 PUFA as adjuvant therapy for patients with cancer, possibly excluding head and neck cancer, owing to their anti-inflammatory properties.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"35 1","pages":"54-65"},"PeriodicalIF":3.6,"publicationDate":"2023-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88873340","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}

引用次数: 0

Design and analysis of novel DGS-loaded low-pass filter with wide stopband 新型dgs负载宽阻带低通滤波器的设计与分析

IF 1.1 4区工程技术

Frequenz Pub Date : 2023-01-13 DOI: 10.1515/freq-2022-0168

Galip Orkun Arican, I. Kanbaz, Zohreh Noamadeh, E. Aksoy

引用次数: 1

Analysis and synthesis of L- and T-shaped flexible compact microstrip antennas using regression-based machine learning approaches 基于回归的机器学习方法分析和综合L形和t形柔性紧凑型微带天线

IF 1.1 4区工程技术

Frequenz Pub Date : 2022-11-16 DOI: 10.1515/freq-2022-0070

M. Bicer

引用次数: 0

Improving the automatic target recognition algorithm’s accuracy through an examination of the different time-frequency representations and data augmentation 通过检查不同的时频表示和数据扩充来提高自动目标识别算法的准确性

IF 1.1 4区工程技术

Frequenz Pub Date : 2022-11-03 DOI: 10.1515/freq-2022-0015

Boban Sazdic-Jotic, Boban P. Bondzulic, J. Bajčetić, M. Andric, I. Pokrajac, Danilo Obradovic, B. Zrnic

{"title":"Improving the automatic target recognition algorithm’s accuracy through an examination of the different time-frequency representations and data augmentation","authors":"Boban Sazdic-Jotic, Boban P. Bondzulic, J. Bajčetić, M. Andric, I. Pokrajac, Danilo Obradovic, B. Zrnic","doi":"10.1515/freq-2022-0015","DOIUrl":"https://doi.org/10.1515/freq-2022-0015","url":null,"abstract":"Abstract This research focuses on an improved automatic target recognition algorithm for solving the classification challenge of ground-moving targets from pulsed-Doppler radar. First, it was studied how decision-making intervals affect the proposed algorithm. Second, the altering of the data augmentation process was investigated. Third, a consideration of the three time-frequency signal representations and finally the use of different deep learning models for the classification issues were examined. It is proven that the proposed algorithm can efficiently recognize all targets enclosed in the publicly available RadEch dataset, with 4 s of radar echoes. When the decision-making time is only 1 s, a classification probability of 99.9% was obtained, which is an improvement related to the other research studies in this area. Furthermore, when the decision-making time is reduced 16 times the classification accuracy is reduced by only 1.3%. Moreover, the proposed algorithm was successful on another dataset enclosing ground-moving targets from comparable pulsed-Doppler radar.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"77 1","pages":"257 - 272"},"PeriodicalIF":1.1,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41910471","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}

引用次数: 1

Radiation pressure of a hybrid bianisotropic chiral structure 杂化双各向同性手性结构的辐射压力

IF 1.1 4区工程技术

Frequenz Pub Date : 2022-11-02 DOI: 10.1515/freq-2022-0118

Samira Nemati Pehrabad, Maoyi Wang, Shitian Zhang, Simin He, Maoyan Wang

引用次数: 0

A 156 GHz high-power doubler-embedded cross-coupled local oscillator in 55 nm CMOS technology 一种156ghz高功率双倍频嵌入式交叉耦合本振，采用55nm CMOS技术

IF 1.1 4区工程技术

Frequenz Pub Date : 2022-10-28 DOI: 10.1515/freq-2022-0104

Sheng-Wen Yang

引用次数: 0

Miniaturized wideband implantable slotted loop antenna for biotelemetry applications 用于生物遥测应用的小型化宽带可植入开槽环天线

IF 1.1 4区工程技术

Frequenz Pub Date : 2022-10-28 DOI: 10.1515/freq-2022-0130

Palanivel Rajan Selvakumaran, P. Mohanraj

{"title":"Miniaturized wideband implantable slotted loop antenna for biotelemetry applications","authors":"Palanivel Rajan Selvakumaran, P. Mohanraj","doi":"10.1515/freq-2022-0130","DOIUrl":"https://doi.org/10.1515/freq-2022-0130","url":null,"abstract":"Abstract Small size of the implantable antenna is the major concern in Implantable Medical Devices. A compact implantable wideband radiator working at the ISM band is proposed for biotelemetry applications. The overall dimension of the proposed radiator is 10 mm ⁎ 15 mm ⁎ 0.8 mm and the thickness includes substrate and superstrate thickness. The Coaxial feeding method is employed here. The inner and outer diameter of the coaxial feed is 1 and 1.5 mm respectively. The design process starts with a creation of rectangular patch of size 10 mm ⁎ 15 mm and the coaxial feed is located at (2.5, 7). Then slot like loops are introduced on a rectangular patch. This compact size is achieved by introducing small loops on a rectangular patch along with triangular cuts at the bottom right and top-left of the patch. The antenna is simulated with a tissue model (Skin, Fat, Muscle, Bone) and measured with a Body Equivalent Fluid (phantom). The −10 dB bandwidth is obtained over 1340 MHz (1.66–3 GHz) and the fractional bandwidth of 54.7% at the ISM band. The simulated gain and radiation efficiency of the radiator are −13.5 dBi and 3.15% respectively. The measured return loss of the proposed antenna is −30.53 dB and the SAR value averaged over 1 g tissue is 302.6 W/kg with 1 W input power. When compared to the previous works mentioned in the literature the proposed antenna displays wider bandwidth, high gain, low SAR and high radiation efficiency.","PeriodicalId":55143,"journal":{"name":"Frequenz","volume":"77 1","pages":"315 - 321"},"PeriodicalIF":1.1,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45185624","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}

引用次数: 0