This paper presents a compact, uni-planer wide band Multiple-Input-Multiple-Output (MIMO) antenna. The designed antenna array has a compact size of (26mm x 31mm) covering a wide frequency band from 3.1GHz - 11GHz. A partial ground plane shared by two radiating patches is used. A ground stub and a single column Electromagnetic Bandgap (EBG) structure in between the two radiating patches results in very low mutual coupling in the designed antenna. The proposed MIMO-antenna was evaluated through different performance metric indicators like channel capacity loss, far-field radiation pattern, S-parameters, envelope correlation coefficient, peak gain, diversity-gain and radiation efficiency. Our designed MIMO antenna has a very high isolation amongst the MIMO antennas ( $\text{S}_{21} < -25$ dB), a high Diversity-Gain (DG $>9.995$ dB), a very low Envelope Co-relation Coefficient of (ECC < 0.001) and low Channel-Capacity-Loss (CCL < 0.1bits/s/Hz). The said antenna has an average radiation efficiency of 85.5% and a peak gain of (5.67dB) within the ultra-wideband (UWB) spectrum. A 0.8mm thick FR-4 substrate is used to fabricate the MIMO-antenna and tested in an anechoic chamber. The measured results closely match with the simulated results.

In the aftermath of unparalleled disruptive technologies, the quantum realm has become a fundamental field of research due to unrivaled computational power and super-secure communication. In addition to conventional networks, a new word in the quantum domain is quantum network. The quantum network uses quantum communication (QC) to send quantum information bits known as qubits, to predetermined destination nodes. It governs the new quantum mechanics notions like superposition, quantum entanglement, the no-cloning theorem, and quantum teleportation. Quantum communication, like classical communication, is prone to noise, which is known as quantum decoherence. Quantum decoherence is a significant barrier to the implementation of a global quantum network. It deteriorates the quantum information, causing it to lie in an undetermined state. Environmental factors that cause quantum entanglement loss are the key factors that cause qubits to lose their states. To mitigate the impact of quantum decoherence, quantum error correction codes (QECC) and entanglement distillation have proved their potential. They add extra qubits or maintain entanglements among quantum networks. This survey presents quantum mechanics principles, quantum decoherence, and techniques to mitigate the effect of quantum decoherence. At the end, we highlighted some challenges in the realization of the quantum network, along with some projected applications.

We propose a novel technique to regenerate the optical signal in a relay-based free space optical link. Our proposed regenerator is based on an Electro-absorption modulator whose optical input is the signal to be regenerated, while the electrical input is extracted by processing a part of the optical input signal. The signal at the output of the proposed regenerator based relay has lower intensity fluctuations compared to a conventional optical amplifier based relay. We have tested our proposed regenerator-based relay under medium and strong turbulence conditions by choosing the refractive index structure parameters as 5×10-15 m-2=3 and 5×10-10 m-2=3, respectively. Our simulation results show that the proposed regenerator-based relay reduces the received power penalty by 3.5 dB compared to the conventional amplifier-based relay, under strong turbulence conditions.

Ultrawideband (UWB) signals have low allowable transmission powers. To enhance the coverage and capacity of UWB signals, a cost-efficient solution for the access network has been proposed and simulated. The access network is based on gamma–gamma free-space optical channel model, which is employed between the central unit and the four different carrier-free radio access units (RAUs). All-optical generation and transmission of UWB signals at a rate of 1.5 Gbps to each RAU are demonstrated. Bit error rate results are obtained to observe the performance of the UWB signals received at the mobile stations. The proposed architecture requires minimum deployment cost and gives acceptable bit error rate results.

In distributed power generation systems, grid-connected inverters are becoming an attractive means of delivering the energy generated from renewable sources into the grid. However, the performance of the current controller drastically decreases in the presence of model uncertainty, grid harmonics, filter parametric, and grid impedance variations, which can jeopardize the entire system’s stability. This paper presents a novel design of a super-twisting integral sliding mode control (ST-ISMC) strategy for the first time in the application of a three-phase voltage source grid-connected inverter. The designed controller has shown robustness and maintains a low total harmonic distortion (THD) in the presence of filter parameters drift, grid impedance variation, and grid harmonics distortion. The super-twisting action is added to remove the chattering problem associated with the conventional SMC strategy, and integral action is adopted to improve the grid’s current steady-state error. The modeling and simulation of a complete system are carried out using MATLAB/SIMULINK. Finally, a real-world hardware prototype system is fabricated to demonstrate the performance and effectiveness of the proposed controller.