Minimizing FWM Impact in DWDM ROF DP-DQPSK System for Optical

The demonstration of a higher data rate transmission system was amajor aspect to be considered by researchers in recent years. The most relevantaspect to be studied and analyzed is the need for a reliable system to handlenonlinear impairments and reduce them. Therefore, this paper examines theinfluence of Four-Wave Mixing (FWM) impairment on the proposed highdata rate Dual polarization–Differential Quadrature phase shift keying (DPDQPSK)system using the Optisystem software. In the beginning, the impactof varied input power on the proposed system’s performance was evaluated interms of QF and BER metrics. More power is used to improve system performance.However, increasing power would raise theFWMeffects. Accordingly,a−10dBminput power and the proposed system are used to reduce the impactof FWM. Additionally, a hybrid amplification method is proposed to enhancesystem performance by utilizing the major amplification methods of erbiumdopedfiber amplifier (EDFA): semiconductor optical amplifier (SOA) andRadio optical amplifier (ROA). The evaluation demonstrates that the OAEDFAoutperformed the other two key amplification techniques of (EDFASOA)and (EDFA-ROA) in improving Quality factor (QF) and Bit error rate(BER) system results for all distances up to 720 km. Consequently, the methodcontributes to minimizing the impact of FWM. In the future, other forms ofnonlinearity will be investigated and studied to quantify their impact on theproposed system.

Compact 5G Vivaldi Tapered Slot Filtering Antenna with Enhanced Bandwidth

Compact fifth-generation(5G)low-frequency band filtering antennas(filtennas)with stable directive radiation patterns,improved bandwidth(BW),and gain are designed,fabricated,and tested in this research.The proposed filtennas are achieved by combining the predesigned compact 5G(5.975–7.125 GHz)third-order uniform and non-uniform transmission line hairpin bandpass filters(UTL and NTL HPBFs)with the compact ultrawide band Vivaldi tapered slot antenna(UWB VTSA)in one module.The objective of this integration is to enhance the performance of 5.975–7.125GHz filtennas which will be suitable for modern mobile communication applications by exploiting the benefits of UWB VTSA.Based on NTL HPBF,more space is provided to add the direct current(DC)biassing circuits in cognitive radio networks(CRNs)for frequency reconfigurable applications.To overcome the mismatch between HPBFs and VTSA,detailed parametric studies are presented.Computer simulation technology(CST)software is used for the simulation in this study.Good measured S11 appeared to be<−13 and<−10.54 dB at 5.48–7.73 and 5.9–7.98GHz with peak realized gains of 6.37 and 6.27 dBi,for VTSA with UTL and NTL HPBFs,respectively which outperforms the predesigned filters.Validation is carried out by comparing the measured and simulated results.

Propagation Characterization and Analysis for 5G mmWave Through Field Experiments

The 5G network has been intensively investigated to realize the ongoing early deployment stage as an effort to match the exponential growth of the number of connected users and their increasing demands for high throughput,bandwidth with Quality of Service(QoS),and low latency.Given that most of the spectrums below 6 GHz are nearly used up,it is not feasible to employ the traditional spectrum,which is currently in use.Therefore,a promising and highly feasible effort to satisfy this insufficient frequency spectrum is to acquire new frequency bands for next-generation mobile communications.Toward this end,the primary effort has been focused on utilizing the millimeter-wave(mmWave)as the most promising candidate for the frequency spectrum.However,though the mmWave frequency band can fulfill the desired bandwidth requirements,it has been demonstrated to endure several issues like scattering,atmospheric absorption,fading,and especially penetration losses compared to the existing sub-6 GHz frequency band.Then,it is fundamental to optimize the mmWave band propagation channel to facilitate the practical 5G implementation for the network operators.Therefore,this study intends to investigate the outdoor channel characteristics of 26,28,36,and 38 GHz frequency bands for the communication infrastructure at the building to the ground floor in both Line of Sight(LOS)and Non-Line of Sight(NLOS)environments.The experimental campaign has studied the propagation path loss models such as Floating-Intercept(FI)and Close-In(CI)for the building to ground floor environment in LOS and NLOS scenarios.The findings obtained from the field experiments clearly show that the CI propagation model delivers much better performance in comparison with the FI model,thanks to its simple setup,accuracy,and precise function.

Asymmetric Patch Element Reflectarray with Dual Linear and Dual Circular Polarization

A reflectarray antenna consisting of asymmetrical patch elements is proposed,which is capable of producing dual linear and dual circular polarized operation at 26GHz frequency.The main purpose of this design is to support four different polarizations using the same patch element.The proposed reflectarray has a single layer configuration with a linearly polarized feed and circular ring slots in the ground plane.Asymmetric patch element is designed from a square patch element by tilting its one vertical side to some optimized inclination.A wide reflection phase range of 600°is obtained with the asymmetric patch element during unit cell measurements.A 332 element circular aperture reflectarray is designed with the proposed configuration and experimentally validated with a linearly polarized prime feed configuration.Two different orientations of mirror and non-mirror asymmetric patch elements on the surface of reflectarray are analyzed.Dual linear polarization is obtained with the mirror orientation of the asymmetric patch elements on the surface of reflectarray.Alternatively,asymmetric patch elements without mirror orientation are demonstrated to produce dual circular polarization with the same linearly polarized feed.A maximum measured gain of 24.4 dB and 26.1 dB is achieved for dual linear and dual circular polarization,respectively.Their respective measured efficiencies are 28%and 41.3%,which are supported by amaximum−3 dB gain bandwidth of 13.8%and 11.5%.The circular polarization operation of the reflectarray is also supported by a 6 dB axial ratio bandwidth of 9.2%.The proposed asymmetric patch reflectarray antenna with polarization diversity,wide bandwidth and high gain is suitable to be used in many high frequency applications of 5G communication.

Linearly Polarized Millimeter Wave Reflectarray with Mutual Coupling Optimization

This work provides the design and analysis of a single layer,linearly polarized millimeter wave reflectarray antenna with mutual coupling optimization.Detailed analysis was carried out at 26GHz design frequency using the simulations of the reflectarray unit cells as well as the periodic reflectarray antenna.The simulated results were verified by the scattering parameter and far-fieldmeasurements of the unit cell and periodic arrays,respectively.Aclose agreement between the simulated and measured results was observed in all the cases.Apart from the unit cells and reflectarray,the waveguide and horn antenna were also fabricated to be used in the measurements.The measured scattering parameter results of the proposed circular ring unit cells provided a maximum reflection loss of 2.8 dB with phase errors below 10°.On the other hand,the measured far-field results of the 20×20 reflectarray antenna provided a maximum gain of 26.45 dB with a maximum 3 dB beam width of 12°and 1 dB gain drop bandwidth of 13.1%.The performance demonstrated by the proposed reflectarray antenna makes it a potential candidate to be used in modern-day applications such as 5th Generation(5G)and 6th Generation(6G)communication systems.