A Novel Densely Packed 4 × 4 MIMO Antenna Design for UWB Wireless Applications

In this article, a compact 4-port UWB (Ultra-Wide Band) MIMO (Multiple Input Multiple Output) antenna is proposed. A low profile FR-4 substrate is used as a dielectric material with the dimensions of 58 × 58 mm2 (0.52λ × 0.52λ) at 2.8 GHz and a standard thickness of 1.6 mm. The proposed design characterizes an impedance bandwidth starting from 2.8 to 12.1 GHz (124.1%). Each of the four elements of the proposed MIMO antenna configuration consists of a monopole antenna with PG (partial ground) that has a slot at its center. The corner of each patch (radiator) and ground slot are rounded for impedance matching. Each unit cell is in an orthogonal orientation, forming a quad-port MIMO antenna system. For reference, the partial ground of each unit cell is connected meticulously with the others. The simulated results of the proposed quad-port MIMO antenna design were configured and validated by fabrication and testing. The proposed Quad-port MIMO design has a 6.57 dBi peak gain and 97% radiation efficiency. The proposed design has good isolation below 15 dB in the lower frequency range and below 20 dB in the higher frequency range. The design has a measured ECC (Envelop Correlation Co-efficient) of 0.03 and DG (Diversity Gain) of 10 dB. The value of TARC (Total Active Reflection Coefficient) over the entire operating band is less than 10 dB. Moreover, the design maintained CCL (Channel Capacity Loss) < 0.4 bits/sec/Hz and MEG (Mean Effective Gain) < 3 dB. Based on the obtained results, the proposed design is suitable for the intended high data rate UWB wireless communication portable devices.

Mutual Coupling Reduction in MIMO DRA through Metamaterials

A single negative metamaterial structure with hexagonal split-ring resonators (H-SRRs) is inserted within a two-port multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) in order to achieve a reduction of mutual coupling between closed multiple antenna elements. Between closed, tightly coupled, high-profile antenna elements, the single negative magnetic inclusions (H-SRRs) are embedded. By incorporating magnetic structures within antenna elements, the mutual coupling is significantly diminished. Mutual coupling reduction is attained by inserting an array of hexagonal split-ring resonators between the inter-spacing elements. An operative approach for the reduction of the mutual coupling between two × two MIMO DRAs initially operating at 5.2-GHz band is provided. To make the simulated design replica of the fabricated prototype, an air gap is introduced between the substrate, DRs, and H-SSRs. The addition of the air gap shifts the simulated results to 5.9 GHz, which closely resembles the measured values. The mutual coupling reduction is realized by integrating a meta-surface amid the two × two MIMO DRAs, which are settled in the H-plane. The meta-surface embraces an array of hexagonal split-ring resonator (H-SRR) cells that are unified along the E-plane. The H-SRR structure is designed to offer band-stop functionality within the antenna bandwidth. The proposed design has an overall dimension of 40 × 58.3 × 4.75 mm3 (1.5λ × 1.02λ × 0.079λ). By stacking the DRA with a one × three array of H-SRR unit cells, a 30 dB reduction in the mutual coupling level is attained without compromising on the antenna performance. The corresponding mutual impedance of the MIMO DRA is better than 30 dB over 5.9-6.1 GHz operating bandwidth. The proposed design has a DG of 10 db, ECC < 0.02, CCL < 0.02 bits/s/Hz, and an MEG of 0 dB. The overall design has a promising performance, which shows its suitability for the target wireless application.

A Self-Decoupling Technique to Realize Dense Packing of Antenna Elements in MIMO Arrays for Wideband Sub-6 GHz Communication Systems

A self-decoupled technique is described that enables the radiating elements in the antenna array to be densely packed for multiple-input multiple-output (MIMO) wireless communications systems. High isolation between the adjacent antenna elements is obtained by fixing the radiating elements in an orthogonal configuration with respects to each other. Current from the adjacent ports cancels their impact which results in low mutual coupling. The additional benefit of this configuration is realizing a densely packed array. The ground plane of each radiating element on the array board itself are isolated to mitigate surface wave propagations to suppress mutual coupling between the antenna elements. The radiating elements are based on a modified edge-fed circular patch antenna that includes a curved slot line and open-circuited stub to widen the array’s impedance bandwidth with no impact on the antenna’s footprint size. The proposed technique was verified with the design of an antenna array of matrix size 4 × 4 centered at 3.5 GHz. The array had a measured impedance bandwidth of 4 GHz from 1.5 GHz to 5.5 GHz, which corresponds to a fractional bandwidth of 114%, peak gain of 3 dBi and radiation efficiency of 84%. Its average diversity gain and envelope correlation coefficient (ECC) over its operating band are 9.6 dB and <0.016, respectively. The minimum isolation achieved between the radiating elements is better than 15 dB. The dimensions of the array are 0.4 × 0.4 × 0.039λ_g^3. The proposed array has characteristics suitable for sub-6 GHz wireless communication systems

Software architecture for pervasive critical health monitoring system using fog computing

Because of the existence of Covid-19 and its variants, health monitoring systems have become mandatory, particularly for critical patients such as neonates. However, the massive volume of real-time data generated by monitoring devices necessitates the use of efficient methods and approaches to respond promptly. A fog-based architecture for IoT healthcare systems tends to provide better services, but it also produces some issues that must be addressed. We present a bidirectional approach to improving real-time data transmission for health monitors by minimizing network latency and usage in this paper. To that end, a simplified approach for large-scale IoT health monitoring systems is devised, which provides a solution for IoT device selection of optimal fog nodes to reduce both communication and processing delays. Additionally, an improved dynamic approach for load balancing and task assignment is also suggested. Embedding the best practices from the IoT, Fog, and Cloud planes, our aim in this work is to offer software architecture for IoT-based healthcare systems to fulfill non-functional needs. 4 + 1 views are used to illustrate the proposed architecture.

STUDY OF KCNJ11 GENE MUTATIONS IN ASSOCIATION WITH MONOGENIC DIABETES OF INFANCY AND RESPONSE TO SULFONYLUREA TREATMENT IN A COHORT STUDY IN EGYPT

Introduction

KCNJ11 gene activating mutations play a major role in the development of neonatal diabetes mellitus (NDM). KCNJ 11 gene encodes the Kir 6.2 subunit of ATP- sensitive potassium channel which is a critical regulator of pancreatic beta-cell insulin secretion.

Aim

To study KCNJ11 gene mutations in infants with NDM and the effect of sulfonylurea treatment on the glycemic control in patients with KCNJ11 gene mutation.

Subjects and methods

Thirty infants with NDM were screened for KCNJ11 gene mutations by DNA sequencing, insulin therapy was replaced by sulfonylurea treatment in patients with mutations.

Results

R201C heterozygous mutation was found in one patient who was successfully shifted from insulin therapy to sulfonylurea treatment, while E23k, I337V, and S385C polymorphisms were detected in 14 patients.

Conclusion

Screening for KCNJ 11 gene mutations could lead to identification of patients with mutations who can be successfully shifted from insulin therapy to sulfonylurea treatment improving their quality of life.

Study of substance P, renin and aldosterone in chronic liver disease in Egyptian children

Substance P is the most powerful endogenous vasodilator peptide produced by the enteric nervous system and partly cleared by the liver. Failure of the diseased liver to metabolize a vasodilator substance may be responsible for the rebound increased plasma level of vasoconstrictor intestinal peptide.

AIM

To investigate the plasma level of Substance P and to study its relationship to aldosterone and plasma renin activity changes occurring in pediatric patients with chronic liver disease.

METHODS

Forty patients with chronic liver disease and 10 healthy children were tested for AST, ALT, total and direct bilirubin, creatinine, aldosterone, plasma renin activity and plasma level of Substance P.

RESULTS

The plasma level of Substance P was increased in all patients with chronic liver disease (119.5+/-68.2 pg/ml) compared to controls (16.2+/-4.6 pg/ml). The aldosterone concentration and plasma renin activity were significantly higher in patients [(84.1+/-38.3 ng/dl) and (11.1+/-7.3 ng/ml/h)] than controls [(8.2+/-3.9 ng/dl) and (2.0+/-1.1 ng/ml/h)]. The highest level of Substance P and aldosterone were observed in glycogen storage disease patients.

CONCLUSION

Substance P was found to be increased in chronic liver disease patients; this increase was accompanied by an increase of aldosterone and plasma rennin activity. This correlation raises its potential use as a prognostic marker in chronic liver diseases.