Simple broadband circularly polarized monopole antenna with two asymmetrically connected U-shaped parasitic strips and defective ground plane

A simple compact broadband circularly polarized monopole antenna, which comprises a simple monopole, a modified ground plane with an implementing triangular stub and two asymmetrically connected U-shaped parasitic strips, is proposed. Simulation results show that the proposed compact antenna (0.62λo×0.68λo) achieves a 10-dB impedance bandwidth (IBW) of 111% (1.7 to 5.95 GHz) and a 3-dB axial ratio bandwidth (ARBW) of 61% (3.3–6.2 GHz) with a peak gain between 2.9–4 dBi for the entire ARBW. With its broad IBW and ARBW, compact size and simple structure, the proposed antenna is suitable for different wireless communications

Electronic bandgap miniaturized UWB antenna for near-field microwave investigation of skin

Near-field microwave investigation and tomography has many practical applications, especially where the trend of fields and signals in different environments is vital. This article shows an elliptical patch ultra-wideband antenna fed by a transmission line for the near-field characterization of cancerous cells in the skin. The antenna comprises an elliptical patch, stub loading to shift the band to lower bands, and an electronic bandgap structure on the ground side. Even though the antenna has a low profile of 15 × 15 mm2, the proposed antenna has more promising results than recent studies. Furthermore, both simulated near-field and far-field results show a broad bandwidth of 3.9–30 GHz and a resonance at 2.4 GHz applicable for industrial, scientific, and medical band applications. The proposed antenna also illustrates a peak gain of 6.48 dBi and a peak directivity of 7.09 dBi. Free space and skin (on a layer of breast fat and a tumor with a diameter of 4 mm at the boundary of skin and breast) are used as test environments during the simulation and measurement of near-field and far-field investigations while considering a phantom breast shape. Both far-field and near-field microwave investigations are performed in Computer Simulation Technology studio, and results are then compared with the measured data. The simulated and measured results are in good agreement, and the focused energy around the tumor is completely reconstructed. Therefore, the proposed antenna can be an adequate candidate for the differentiation of breast skin and tumor to reconstruct the tumor’s image

New CPW-Fed Broadband Circularly Polarized Planar Monopole Antenna Based On A Couple Of Linked Symmetric Square Patches

A new broadband circularly polarized planar monopole antenna with coplanar waveguide feeding (CPW-fed) is proposed. This antenna consists of a couple of linked symmetric square patches (CLSSP), an asymmetric ground plane and two strips connected to the left ground plane by the CLSSP radiator and a straight strip. A broad impedance bandwidth (IBW) is achieved. Moreover, a broad axial ratio bandwidth (ARBW) is obtained by using an asymmetric ground plane and an inverted L-shaped strip. Simulation results demonstrate that IBW reaches 119% (1.56-6.18 GHz) and ARBW is 88.9% (2-5.2 GHz). The latter is completely overlapped by the simulated IBW. In addition, antenna performance is investigated by studying different parameters

Performance Evaluation Of Peak-To-Average-Power Ratio Reduction Techniques In OFDM

The high demand of using wireless communication leads to establish a new technique of modulation to enhance the throughput of the system and to have a high data rate communication. One of the modern wireless modulation techniques is the Orthogonal Frequency Division multiplexing (OFDM) which considered a suitable technique of modulation in modern wireless application. But there is an important issue to make into consideration when designing OFDM which is the Peak to Average Power Ratio Reduction (PAPR). This study provides a full comparison between using several techniques of PAPR reduction like Clipping and Filtering, Partial Transmit Sequence, DFT Spreading, and Selective Mapping techniques. These techniques are simulated and the PAPR results are obtained for each technique. The comparison between results is also obtained and verified experimentally using MATLAB. The simulation results show that Clipping and filtering technique is the simplest technique of reducing PAPR ratio of the OFDM signal, it depends on the clipping level that satisfies the Signal to Quantization Noise Ratio SQNR. They also show that the partial transmit and selective mapping techniques depends on dividing the OFDM signal into subsignals which the result of transmission these subsignals is nearly to that obtained for the base band signal transmission. The use of Selective Mapping technique (SLM) leads to a PAPR reduction in the simulation from nearly 18 for normal OFDM signal to 12.8 for SLM-OFDM signal. The PAPR ratio from the clipping and filtering technique is 9.5 while the PAPR from SLM is 16.4. The efficiency obtained from the simulation of the SLM technique and clipping and filtering technique are 28.6 and 58.4 respectively

A Comprehensive Survey, Benefits, Services Recent Works Challenges Security And Use Cases For SDN-VANET

Vehicular communication networks is a powerful tool that enables numerous vehicular data services and applications. The rapid growth in vehicles has also resulted in the vehicular network becoming heterogeneous, dynamic, and large-scale, making it hard to meet the strict requirements, such as extremely latency, high mobility, top security, and enormous connections of the fifth-generation network. Previous studies have shown that with the increase in the application of Software-Defined Networking (SDN) on Vehicular Ad-hoc Network (VANET) in industries, researchers have exerted considerable efforts to improve vehicular communications. This study presents an exhaustive review of previous works by classifying them based on based on wireless communication, particularly VANET. First, a concise summary of the VANET structure and SDN controller with layers and details of their infrastructure is provided. Second, a description of SDN-VANET applications in different wireless communications, such as the Internet of Things (IoT) and VANET is provided with concentration on the examination and comparison of SDN-VANET works on several parameters. This paper also provides a detailed analysis of the open issues and research directions accomplished while integrating the VANET with SDN. It also highlights the current and emerging technologies with use cases in vehicular networks to address the several challenges in the VANET infrastructure. This survey acts as a catalyst in raising the emergent robustness routing protocol, latency, connectivity and security issues of future SDN-VANET architectures

Simple broadband circularly polarized monopole antenna with two asymmetrically connected U-shaped parasitic strips and defective ground plane

A simple compact broadband circularly polarized monopole antenna, which comprises a simple monopole, a modified ground plane with an implementing triangular stub and two asymmetrically connected U-shaped parasitic strips, is proposed. Simulation results show that the proposed compact antenna (0.62λo×0.68λo) achieves a 10-dB impedance bandwidth (IBW) of 111% (1.7 to 5.95 GHz) and a 3-dB axial ratio bandwidth (ARBW) of 61% (3.3-6.2 GHz) with a peak gain between 2.9-4 dBi for the entire ARBW. With its broad IBW and ARBW, compact size and simple structure, the proposed antenna is suitable for different wireless communications

New CPW-fed broadband circularly polarized planar monopole antenna based on a couple of linked symmetric square patches

A new broadband circularly polarized planar monopole antenna with coplanar waveguide feeding (CPW-fed) is proposed. This antenna consists of a couple of linked symmetric square patches (CLSSP), an asymmetric ground plane and two strips connected to the left ground plane by the CLSSP radiator and a straight strip. A broad impedance bandwidth (IBW) is achieved. Moreover, a broad axial ratio bandwidth (ARBW) is obtained by using an asymmetric ground plane and an inverted L-shaped strip. Simulation results demonstrate that IBW reaches 119% (1.56–6.18 GHz) and ARBW is 88.9% (2–5.2 GHz). The latter is completely overlapped by the simulated IBW. In addition, antenna performance is investigated by studying different parameters