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Fifth generation (5G) mobile communication systems have been deployed in the millimeter wave (mmWave) band. Since electromagnetic (EM) waves in this band exhibit high propagation loss and antennas are highly directive, the performance of wireless communications is largely degraded in a non-line-of-sight (NLOS) area, resulting in a limited coverage area. To improve the performance and increase the coverage area, a metamaterial-based electromagnetic scattering sheet (EMSS) with broad scattering characteristics is proposed in this paper. We also introduce fast design and optimization methods using equivalent circuits of metamaterials, antenna array theory, and the genetic algorithm (GA). The diffusion coefficient is used as a fitness value to evaluate the scattering characteristics of the EMSS generated by GA. The broad scattering characteristics of the designed EMSS are experimentally confirmed. We clarified that the optimized EMSS has a higher diffusion coefficient than a metal plate of the same size. Finally, we demonstrated improved wireless communication performance in an NLOS area by diffusing the incoming EM fields using our designed EMSS.

Summary: Microstrip patch antennas (MPA) are widely used in wireless communication systems due to their ease of manufacture, low cost, and low profile. This work proposes a proximity‐coupled rectangular microstrip patch antenna array (PRMPA) adaptable for 5G applications. However, the existing research works suffered from low gain, low efficiency, and narrow bandwidth. In addition, 5G communications suffer from path loss in high‐frequency bands. For managing this issue, the large gain antenna is essential. Hence, this research aims to design and fabricate high‐gain compact 2 × 2 slotted PRMPA for 5G applications. The antenna design is simulated on HFSS and operates at 28–37 GHz. Here, the antenna parameters like length, width, and feed line parameters are optimized using a metaheuristic optimization like the mayfly optimizer (MFO). Further, a circular‐shaped metamaterial split‐ring resonator (SRR) reduces the mutual coupling. Then, Rogers RT5880 is used as substrate material, and the design operates at 34.5 GHz. The gain and radiation efficiency achieved by the proposed antenna design are 15.4 dB and 94.4% for the simulated outcomes. Highlights: This research aims to introduce a compact 2 × 2 proximity‐coupled rectangular microstrip patch antenna (PRMPA) array for 5G communications at 28–37 GHz bands.This study's aim is to introduce a metaheuristic algorithm mayfly optimizer (MFO) to optimize the antenna's dimensions (length and width).This study provides the slots in a corner on both sides of the antenna to improve the gain and efficiency.This research aims to demonstrate the parameters of designed antennas, like single element and 2 × 2 array; they are compared based on gain, bandwidth, voltage standing wave ratio (VSWR), reflection coefficient, and radiation efficiency. [ABSTRACT FROM AUTHOR]

Secured broadband radio communications are becoming increasingly pivotal for high-speed connectivity in radio access networks, playing a crucial role in both mobile information systems and wireless IoT connections. This paper introduces a chaos-based two-channel digital radio communication system utilizing fiber optic radio transmission technology. The system comprises two radio channels operating at up to 1 Gbps using amplitude shift keying (ASK) modulation, followed by modulation with a chaotic sequence before conversion to the optical domain using the MZM modulator. To compensate for fiber loss, the system utilizes an Erbium-Doped Fiber Amplifier (EDFA) and employs the optical links through standard ITU-G.655 optical fibers. Numerical simulation of the designed system is performed using the commercialized simulation software Optisystem V.15 to assess and characterize transmission performance. The results demonstrate the system's effective operation on two channels with a fiber transmission distance of up to 110 km, maintaining a bit error ratio of less than 10-9. This feature ensures reliable performance for high-speed radio connections, particularly in applications such as fronthaul networks in cloud radio access and wireless sensor network connections. [ABSTRACT FROM AUTHOR]

In a wireless communication chain, filters play a critical role in ensuring the efficiency, reliability, and overall performance of the system. In fact, filters are essential for selecting specific frequency bands. They can narrow or widen the bandwidth, depending on the requirements of the communication protocol. Appropriate bandwidth management is crucial for optimizing data transmission rates and accommodating multiple channels within the available spectrum. This article describes the design of a compact bandpass filter with two identical rectangular open-loop resonators. The proposed filter frequency response covers the 3.5 GHz global interoperability for microwave access (WiMAX) and fifth generation (5G) applications. The structure of this filter uses the Rogers RO6010 substrate, which has a dielectric constant of 10.2, thickness of 1.27 mm, and tangent loss of 0.0023. The proposed device is intended for wireless communication systems operating at 3.5 GHz. The filter offers a wide bandwidth of 1.21 GHz with a small size of (5.72 × 12.34) mm2, and a low insertion loss of −0.16 dB. The suggested filter offers effective utilization across various applications including fifth-generation (5G), sub-6G, and WiMAX. Simulation and optimization of the proposed design are conducted utilizing the HFSS (High Frequency Structure Simulator) software. To corroborate the results from HFSS, the ADS (Advanced Design System) software is employed. The simulation outcomes obtained from both HFSS and ADS simulators demonstrate close resemblance.

This paper is devoted to dynamic network flows. A phenomenon called dynamic network flow splash is studied (splash is an exceeding of flow value over maximum feasible static flow for the same network). Parallel and tree-structured network topology classes are defined. Conditions for occurring network flow splash in the parallel and tree-structured networks are discovered. A formula for computing a value of maximum dynamic network flow splash is obtained. An algorithm for calculating the formula values is presented., Author(s): I. M. Erusalimskiy [sup.1], V. A. Rusakov [sup.1] Author Affiliations: (1) https://ror.org/01tv9ph92, grid.182798.d, 0000 0001 2172 8170, Institute of Mathematics, Mechanics and Computer Science, Southern Federal University, , 8a [...]

In this paper, a dual-polarized antenna fed by CPW is presented. The proposed includes a conductor on the ‎radiator and has defected ground, so it has been achieved as an omnidirectional antenna which makes it a low loss, ‎and a simple antenna which is appropriate for a wireless communication system. By imposing the different ‎circumstances of U-shape elements on the ground, the features of antennas have been improved. The scattering ‎characteristic of the antenna are less than -20 dB with high impedance matching at 2.2GHz, 4.8GHz, and 6.6GHz. ‎Also, the antenna covers 400 MHz bandwidth from 2 GHz to 2.4 GHz, 500 MHz bandwidth from 4.6 GHz to 5.1 GHz, ‎and 1.3 GHz bandwidth from 5.7 GHz to 7 GHz, respectively. In addition, the maximum gain of the antenna is almost ‎‎10 dB. The simple and compact antenna with an overall size of 25x20mm2 is designed on an FR-4 substrate with 0.8 ‎mm thickness. On the one hand, the structure is fabricated and tested. The results of the antenna have shown that ‎the measured results agree with the simulated results; The performance of the antenna with CPW-fed, consisting of ‎compact size, circular polarization, and suitable gain at resonance frequencies, make it a suitable choice for the ‎communication system and the portable device.‎