Purpose of Review Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is identified from Wuhan, China, and has spread almost worldwide. Recently, the newly identified SARS-CoV-2 has been confirmed to kill millions of people worldwide and is dangerous to society health, survival, and livelihood. The people with cardiovascular problems are noticed as most common patients of coronavirus disease 2019 (COVID-19). There is a greater risk of mortality and morbidity in these patients than other patients of COVID-19. In the heart, expressed angiotensin-converting enzyme 2 (ACE2) and response effect of hyperactivity with angiotensin II associated to the renin-angiotensin mechanism are key factors of hypertension, atherosclerosis, and congestive heart failure. Recent Findings Mortality rates have been observed about 10.5% cases in patients with cardiovascular disease; however, a mortality rate of 52% was recorded in patients with heart failure, while 12% recovered ultimately. The occupancy of intense injury controlled by troponin elevation was a noteworthy factor in relation to mortality. Among 187 patients infected with SARS-CoV-2, about 35% were diagnosed with cardiovascular disease (CVD) history and 28% with raised troponin. Troponin elevation was identified more frequently (55%) in patients with cardiovascular diseases. Mortality rate in patients without cardiovascular diseases and normal troponin was 7.6%, normal troponin and cardiovascular disease with 13.3%, augmented troponin and without cardiovascular disease 37.5%, however 69.4% among cardiovascular disease and advanced troponin. Summary The study reflected a significant association of case fatality rate (CFR) to COVID-19 patients with cardiovascular diseases which supposed to be the most common dangerous risk factor and health challenge during the current pandemic situation.
The growing need of the compact and portable antennas with high speed and low latency wireless communication is the present and future demand of the voice over Internet protocol, on-demand bandwidth, and multimedia applications. Fifth-generation (5G) covers certain low-frequency bands under 6 GHz spectrum, and most of the high-frequency bands under 60 GHz. 5G is the part of the millimeter wave spectrum (30–300 GHz) and is introduced to overcome the problem of spectrum shortage due to exponential enhancement of wireless applications in industry, medical, airborne, radar, satellite, and research fields. The International Telecommunication Union's objective of wireless communications promises to provide higher data rates up to 10 Gbps for 5G mobile users and connectivity to the artificial intelligence devices, along with high spectral efficiencies and enhanced coverage. The users for the 5G require around 5 and 50 Gbps of data rates for low and high mobility, respectively. Beamforming in 5G is the modern powerful technique for the coverage of the intended user/direction using the narrow beam width radiation patterns. A brief survey on 5G beamforming techniques, i.e. analog, digital, hybrid, switched, and adaptive etc. and its types, working algorithms, design of compact antennas, gain, and size/type of the substrates is carried out in this paper. The study of the hybrid coupler, branchline coupler, Wilkinson power divider, and Butler matrix in beamforming is required for 5G smart antennas. Different beam widths like ±15, ±35, ±45, and ±55° etc. are produced for the intended directions using a variety of beamforming techniques. From lower to higher frequency band beamforming applications with Roger's Duroid 4003/4350/5880, tectonic, and aluminum oxide dielectric substrates are discussed here. Various beamforming techniques with their merits, demerits, and applications are included in the paper for the knowledge extension of the beamforming antenna designers and research community.
For the first time, integration of a commercial single-pole four-throw RF switch with beam steerable square loop antenna is presented. By controlling the switch bias the high gain tilted beam of the antenna can be steered electronically in all the four space quadrants. A model of the complete integrated switch with the antenna has been developed and simulated. Further, for achieving distortion-free patterns and errorfree simulation comments are made on the placement of the RF switch and associated meshing considerations. For the test band (4.3 -5.0 GHz) the antenna generates a steerable tilted beam with a directivity of 8.0 dBi + 0.4 dB.
As the demand for high data rates is increasing day by day, fifth-generation (5G) becomes the leading-edge technology in wireless communications. The main objectives of the 5G communication system are to enhance the data rates (up to 20 Gbps) and capacity, ultra-low latency (1 ms), high reliability, great flexibility, and enhance device to device communication. The mentioned objectives lead to the hunting of the millimeter-wave frequency range which lies from 30 to 300 GHz for 5G wireless communications. To design such high capacity, low latency, and flexible systems, antenna design is one of the crucial parts. In this paper, a survey is presented on various antenna designs with their fabrication on different types of substrates such as Rogers RT/duroid 5880, Rogers RO4003C, Taconic TLY-5, etc., at different 5G frequency bands. The different configurations of antennas that covered antenna arrays, multiple-input multiple-output (MIMO) antennas, phased antennas, and beamforming antennas are discussed in detail with their applications. The design of MIMO antennas in the 5G frequency band occupied less space so mutual coupling reduction techniques are required for maintaining the required gain, efficiency, and isolation. This paper is also focused on the mutual coupling reduction techniques and diversity in MIMO antennas.
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