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In this paper, a complementary split ring resonator (CSRR) loaded compact CPW-fed circular shaped monopole UWB antenna with dual band notch characteristics is designed on an FR-4 substrate. The propounded band-notched UWB antenna is integrated with two frequency selective surface layers referred as bandpass frequency selective surface (FSS-1) and reflector (FSS-2) to offer enhanced radiation performance. Bandpass FSS-1 enhances the gain of the antenna by improving directivity and reflector FSS-2 reflects back the backside radiation of the proposed antenna towards the forward direction thereby increasing gain and directivity of the proposed antenna. Furthermore, a two-element orthogonal MIMO antenna is proposed with improved gain using two FSS layers. The complete configuration of the proposed two-element MIMO antenna consists of CSRR-based radiating patches, monopole ground planes and two integrated FSS layers. The proposed MIMO antenna operates in UWB range from 3.46 GHz to 16.02 GHz with dual notches at 3.9 GHz and 7.2 GHz. Isolation between MIMO elements is greater than 23 dB. Both antennas are fabricated and investigated at 5.9 GHz for vehicular communications. Maximum gain improvements of 8 dB and 6.4 dB are observed in case of the presented single element and MIMO antenna within the entire operating band due to the integration of dual FSS layers. The diversity performance of the suggested MIMO antenna is investigated by analyzing mean effective gain, envelope correlation coefficient, channel capacity loss and diversity gain parameters. The proposed MIMO antenna is a suitable candidate for vehicular and UWB wireless communication applications. [ABSTRACT FROM AUTHOR]

In this paper, the performance of Optical Wireless Communication (OWC) under atmospheric turbulence and pointing errors is enhanced by employing MIMO transceivers and heterodyne BPSK and DPSK modulations. We have derived new closed-form expressions for the bit error rate (BER) of MIMO optical wireless communications based on BPSK and DPSK with heterodyne detection for atmospheric turbulence only, pointing error only, and both effects combined. Numerical simulations reveal that the effect of turbulence and pointing errors increases with Rayleigh variance and normalized jitter variance, while it diminishes with normalized pulse width. The BER values for SISO-BPSK and SISO-DPSK, considering a normalized pulse width of 4, normalized jitter of 2, Rayleigh variance of 2, and SNR of 16 dB, are 7.50 × 10 - 3 and 1.48 × 10 - 2 , respectively. It is evident that the BER of SISO OWC experiences significant degradation for both modulation techniques. However, through the employment of a MIMO transceiver with an increased number of receivers and transmitters, the BER experiences a substantial reduction. The BER values for MIMO-BPSK and MIMO-DPSK under the same conditions are remarkably low, standing at 1.24 × 10 - 12 and 2.38 × 10 - 10 , respectively. These results underscore that, for both SISO and MIMO systems, BPSK outperforms DPSK. The power penalty of SISO-BPSK, for Rayleigh variance and normalized pulse width, is twice that of MIMO-BPSK under the same conditions. The results show that we can use MIMO with heterodyne BPSK to reduce the BER caused by atmospheric turbulence and pointing errors. [ABSTRACT FROM AUTHOR]

The primary focus of this paper is to evaluate the channel capacity of a Terahertz (THz) communication system using a Multiple Input Multiple Output (MIMO) technique. By deriving mathematical expressions for channel capacity and considering practical constraints, the paper provides insights into the performance of such systems under various conditions. The channel model used in this work accommodates the channel accuracies and transceivers constraints. To validate the proposed channel capacity, some simulations by taking into account deferent parameters namely SNR (Signal to Noise Ratio), MIMO channel Matrix size, and distance between transmitter and receiver are performed. These simulations are carried out for 3 cases which are: (1) Channel State Information CSI is known to both transmitter (Tx) and receiver (Rx), (2) CSI is known to Rx but unknown to Tx, (3) CSI is unknown to both Tx and Rx. In this study, we introduce a mathematical formulation for a communication channel tailored for Terahertz (THz) applications. Using this channel model, we analyze the capacity of the THz channel. The suggested research has the potential to be applied in the design and enhancement of Terahertz (THz) wireless communication systems, aiding in the advancement of robust and high-capacity wireless networks that can fulfill the requirements of contemporary multimedia applications. [ABSTRACT FROM AUTHOR]

This paper deals with the design, simulation, and practical modeling of metamaterial-based multiband conformal bandpass filter (BPF) for various wireless communication applications with improved quality factors. The novel metamaterial in the form of a split ring resonator is loaded on the ground plane face of the proposed BPF. The overall dimension of the designed BPF is only 2 8 × 2 8 mm 2 . The proposed BPF is tuned initially for quality factor enhancement based on the thickness of the substrate, physical parameters of the f transmission line, ground plane, externally loaded elements, and the gap in the metamaterial loading. The suggested filter operates at triple band covering the frequency bands from 1.4 to 2.2, 3.6 to 3.9, and 4.8 to 5.9 GHz, which are suitable for sub-6 GHz 5G and other wireless applications. The insertion loss is observed as 1 dB, which is suitable for the proposed BPF. The conformal behavior of the filter is judged through bending deformation analysis at various bending positions like (15 ∘ , 30 ∘ , 45 ∘ , 60 ∘ , and 90 ∘ ). The proposed BPF retains triple pass band characteristics at various bending deformations, which makes it suitable to be used in curved structures or flexible circuitry. The theory of equivalent circuits and quality factor (Q) of the designed BPF is discussed in this paper. The results are analyzed experimentally through ANRITSU-MS2037C combinational analyzer. The proposed BPF is suitable for sub-6 GHz 5G, WLAN, and Wi-Max applications. [ABSTRACT FROM AUTHOR]

Metamaterial technology indeed holds great promise for enhancing wireless communication, especially in the development of advanced filters and devices. The use of metamaterials for filter design is an exciting and promising area of research, driven by their exceptional properties and potential for revolutionizing various technological applications. In fact, Metamaterials can be engineered to exhibit unique electromagnetic properties, allowing for precise control of the filtering characteristics. This enables designers to create filters with sharp passbands and stopbands, as well as customizable cutoff frequencies. Besides, Metamaterials can be used to miniaturize filters, making them suitable for compact and portable devices. This is especially valuable for applications with size constraints, such as mobile phones and wearable technology. Moreover, Metamaterials provide the flexibility to design filters with adjustable bandwidth. In this paper, a triple band pass printed filter using split-ring resonators is designed and simulated. The proposed filter is composed of two split-ring arrays loaded on the transmission line. It is printed on a Rogers RT/duroid 6010/6010LM (tm) substrate. The proposed BPF has a small size (14 × 16 mm²) and high selectivity. The simulation result exhibit three passbands centered at 3.15 GHz, 6.27 GHz and 9.31 GHz, respectively with required return loss and insertion loss characteristics. The simulation studies are carried out with HFSS software and its electrical equivalent circuit model (ECM) is designed using ADS tool. The results obtained using HFSS is in well agreement with ECM results. [ABSTRACT FROM AUTHOR]

This paper describes a four-port MIMO antenna array design featuring bow-tie-shaped slot-loaded patches with wideband capabilities that cover the frequency range from 24.2 GHz to 30.8 GHz. The proposed antenna design is printed on an FR4 substrate and occupies an area of 25 × 24 mm2. The MIMO antenna consists of four antenna arrays that are symmetrically placed in an upper-lower configuration. The bow-tie-shaped slots loaded radiators are separated horizontally by 3.48 mm and vertically by 5.94 mm. Each antenna array contains two elements that are separated by a distance of wavelength/4. The suggested MIMO antenna array delivers a high gain of 19.09 dB at 27.8 GHz and has a bandwidth of 6.6 GHz that covers the frequency band of 24.2–30.8 GHz. The research demonstrates the quality of the proposed MIMO antenna through various diversity parameters such as mutual coupling, port correlation, diversity gain, and data rate that can be transmitted over a communication medium. The simulation results are validated and found to be consistent with the experimental results. The presented antenna covers the entire bandwidth allocated to different regions, including Europe (24.25–27.5 GHz), Sweden (26.5–27.5 GHz), USA (27.5–28.35 GHz), China (24.25–27.5 GHz), Japan (27.5–28.28 GHz), and Korea (26.5–29.5 GHz). The proposed MIMO antenna design could be an excellent option for 26/28 GHz 5G NR n257, n258, and n260 bands under mm-wave wireless communication systems. [ABSTRACT FROM AUTHOR]

The growing popularity of IoT (Internet of Things) and its applications is evident from the increasing number of connected devices and IoT services. To enable connectivity for these devices, various wireless low-power and wide-area networks (LPWAN) have been established. In this paper, recombination mechanisms within the Receiver for IoT Based Applications were analyzed. Indeed, the principle on which the repetitions mechanism is based is simple: to emit a repetition is to increase the total energy dedicated to the information, and to increase this energy is theoretically to facilitate the demodulation of the information at the receiver stage. In this particular research, the focus is on evaluating the effectiveness of various diversity combiners employed at the receiver. To conduct the analysis, a transmission chain based on GMSK (Gaussian Minimum Shift Keying) modulation is proposed. Simulation results show that increasing the number of repetitions decreases the BER (Bit Error Rate) of the considered mechanism. Furthermore, simulation shows that the EGC (equal-gain combining) and SC (selection combining) mechanisms are very sensitive to the speed of evolution of the channel. However, the performance of MRC (maximal ratio combining) mechanism changes slightly when the transmitter speed increases; especially, at low SNR (signal-to-noise ratio). [ABSTRACT FROM AUTHOR]

A staircase-shaped printed monopole antenna (SPMA) with a partial ground structure for wireless applications is proposed. The performance parameters of the designed antenna have been evaluated by integrating a novel structure of frequency selective surface (FSS) with the antenna. A Polyimide dielectric material has been utilized for designing both the antenna and the FSS reector. The proposed SPMA integrated with designed FSS reector operates at dual bands from 2.18 to 2.83 GHz and 4.42 to 5.58 GHz with fractional impedance bandwidth of 25.94% and 23.2%, respectively. A single-layered FSS reector with a 5×5 array size is employed to obtain optimum performance. The suggested combined structure of the FSS reector integrated staircase antenna achieves an attractive peak gain of 7.87 dBi and radiation efficiency of 98.8%. The design methodology for the antenna and unit cell design of the required FSS, analysis of field and current distributions, fabricated prototyped models of antenna and FSS along with measured results are included and discussed in this article. The proposed antenna is suitable for modern wireless communication (WLAN/Wi-Fi etc.) applications at 2.4/5.2 GHz. [ABSTRACT FROM AUTHOR]

The choice of modulation and waveform is a crucial step for generating a radio signal and designing a wireless communication system. Toward this end, a compromise between low‐complexity and high‐data rate had to be considered when selecting the appropriate transmission technique. Indeed, pulse‐based modulation can be a good candidate for THz system due to its simplicity and it supports very high data over short distance. In this work, we proposed a solution based on multiband on–off keying (MB‐OOK) modulation using a noncoherent receiver. A deferential MB‐OOK transceiver has been evaluated over a THz channel model. A data rate of 54.24 Gbps is achieved with a BER of 10–3 when the distance between transmitter and receiver less than 35 m. Furthermore, the proposed system offers a good compromise between throughput, consumption, and complexity, which allow it to be a good candidate for THz applications. [ABSTRACT FROM AUTHOR]

For several years, the fields of new technologies have been experiencing a real boom. The use of the terahertz band is an appropriate solution to meet the requirements of these technology. However, this technology has special requirements among which its antennas must have high bandwidth of few THz and achieve high gain for high productivity. In this paper, we will focus on the design and analysis of an antenna for THz technology. The antenna structure proposed in this work has better performance in terms of bandwidth and gain. In fact, multiples slots were added to the antenna to enhance the antenna's bandwidth. In addition, to enhance the antenna performance in terms of gain and protect the antenna feed line against environmental jeopardies a thin layer as superstrate is used. The suggested antenna covers a wide −10 dB bandwidth from 0.9 to 17.3 THz with a peak gain of 12.8 dBi. Moreover, a VSWR less than 2 at the operating band is obtained. Furthermore, the suggested antenna has circular polarized radiations with an axial ration (AR) less than 3 dB over a wide band 13.6–17.3 THz which mean that the proposed antenna is well suited for application where the transmitter and receiver are moving which is the most case for wireless system. Thus, the suggested THz antenna could be a successful choice for terahertz application like future high-speed short-range indoor wireless communication, explosive detections, arms detection, medical imaging, pharmaceutical analysis, and material characterization in the THz regime industrial inspections. [ABSTRACT FROM AUTHOR]

The ever-increasing demand for wireless communication services, driven by the proliferation of mobile devices, the surge in data-hungry applications, and the expansion of the Internet of Things (IoT), has placed immense pressure on available bandwidth resources. In response to this pressing issue, researchers and engineers have turned to MIMO technology as a promising solution. In the context of future fifth-generation (5G) terminals, achieving optimal isolation while maintaining a compact size remains a formidable challenge. This challenge arises from the increasing demands placed on 5G devices, which require efficient and high-performance antenna systems in constrained form factors. Until now, numerous antennas utilizing metamaterials have been proposed. However, a comprehensive review based on key enhancement techniques is still lacking in the literature. Consequently, we aim to conduct a comprehensive examination of the numerous types of 5G metamaterial-based single and MIMO antenna designs in this study. [ABSTRACT FROM AUTHOR]