2022/1
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- ItemRadome Enclosed Circularly Polarized Antenna System with Enhanced Beamwidth(Společnost pro radioelektronické inženýrství, 2022-04) Pradhan, Suman; Gupta, BhaskarThis paper presents a circularly polarized (CP) patch antenna system enclosed by a nosecone radome which has a wide beam response. A U-slot loaded corner truncated patch antenna is mounted upon a conical ground structure for achieving the wide beam response. When two such antennas, one Right Handed CP (RHCP) and another Left Handed CP (LHCP) are placed inside a nosecone radome, a drastic reduction in the antenna beamwidth is observed. Finally a metallic conical ring is added to the structure which improves the beamwidth of the antenna and we achieve a beamwidth of 74° and 120° in the ϕ=0° and ϕ=90° planes respectively. The antenna system also provides a good axial ratio bandwidth performance.
- ItemMultiobjective Reinforcement Learning Based Energy Consumption in C-RAN enabled Massive MIMO(Společnost pro radioelektronické inženýrství, 2022-04) Sharma, Shruti; Yoon, WonsikMultiobjective optimization has become a suitable method to resolve conflicting objectives and enhance the performance evaluation of wireless networks. In this study, we consider a multiobjective reinforcement learning (MORL) approach for the resource allocation and energy consumption in C-RANs. We propose the MORL method with two conflicting objectives. Herein, we define the state and action spaces, and reward for the MORL agent. Furthermore, we develop a Q-learning algorithm that controls the ON-OFF action of remote radio heads (RRHs) depending on the position and nearby users with goal of selecting the best single policy that optimizes the trade-off between EE and QoS. We analyze the performance of our Q-learning algorithm by comparing it with simple ON-OFF scheme and heuristic algorithm. The simulation results demonstrated that normalized ECs of simple ON-OFF, heuristic and Q-learning algorithm were 0.99, 0.85, and 0.8 respectively. Our proposed MORL-based Q-learning algorithm achieves superior EE performance compared with simple ON-OFF scheme and heuristic algorithms.
- ItemSmall Size Wideband Monopole Antenna with Five Notch Bands for Different Wireless Applications(Společnost pro radioelektronické inženýrství, 2022-04) Bala, Susmita; Reddy, P. Soni; Sarkar, Sushanta; Sarkar, Partha PratimA broadband planar monopole antenna with five notch bands is proposed here. The antenna provides broadband from 1.94 GHz to 15.4 GHz with five notch bands covering 3.1-4.1 GHz, 6-6.4 GHz, 8.2-9.2 GHz, 10-11.6 GHz, and 12.38-12.89 GHz. These notch bands are effectively used to remove undesired interferences from the WiMAX (3.2-3.8 GHz), partial standard C band (5.850-6.415 GHz), partial ITU band (8.025-8.4 GHz), partial X band (8-12 GHz), and partial Ku downlink frequency band (12.2-12.7 GHz). The notch bands have been realized by etching three notch elements on the patch, feed line, and two small narrow open-ended slots on the ground plane. The design of the proposed antenna is very simple and it utilizes only the volume of 20×40×1.6 mm3. The antenna is useful for wideband fast data communication systems.
- ItemClassification of Microwave Planar Filters by Deep Learning(Společnost pro radioelektronické inženýrství, 2022-04) Vesely, Jiri; Olivova, Jana; Gotthans, Jakub; Gotthans, Tomas; Raida, ZbynekOver the last few decades, deep learning has been considered to be powerful tool in the classification tasks, and has become popular in many applications due to its capability of processing huge amount of data. This paper presents approaches for image recognition. We have applied convolutional neural networks on microwave planar filters. The first task was filter topology classification, the second task was filter order estimation. For the task a dataset was generated. As presented in the results, the created and trained neural networks are very capable of solving the selected tasks.
- Item28 GHz Switched Beam Vivaldi Antenna System for V2V Communication in 5G Applications(Společnost pro radioelektronické inženýrství, 2022-04) Ameen, Allam M.; Ahmed, Mohamed, I; Elsadek, Hata; Anis, Wagdy R.A 28GHz switched beam Vivaldi antenna system consisting of 4 Vivaldi antennas for V2V communication is presented. The proposed design is realized on a substrate material of “Rogers 5880” with ε_r=2.2,tanδ=0.002 and 0.508 mm substrate thickness. The antenna is designed to operate at a center frequency of 28 GHz with operating bandwidth of 1.463 GHz (5.23%). An overall realized gain of 9.78 dBi is achieved at the intended center frequency. The proposed antenna is designed and simulated. It is also fabricated using photolithography techniques and measured using R&S vector network analyzer. Good agreement is obtained between both simulated, and measured results.