R. Ramasamy

Recent advancements in wireless communication technologies and Internet‐enabled devices have accelerated the demand for compact, efficient antennas suitable for body‐centric applications. This study presents a compact, high‐performance dual‐frequency antenna featuring an artificial magnetic conductor (AMC) surface for next‐generation wireless systems. A modified gear‐wheel radiating patch on top and a partial ground plane on the bottom comprise the antenna, making it a three‐layer antenna. A circular patch overlays 12 radiating teeth, enabling a dual wideband response. The AMC surface comprises a 4 × 4 array of unit cells, each incorporating slotted square and rectangular patches. The unit cells exhibit double‐negative (DNG) properties and operate in three frequency regions. The zero‐degree reflection phase occurs at 2.5 GHz, 4.1 GHz, and 6.5 GHz. The integrated antenna covers impedance bandwidths of 71.79% (2.0–4.24 GHz) and 41.67% (5.13–7.83 GHz), encompassing key wireless frequency bands, while maintaining compact dimensions of 0.554 λ ₀ × 0.554 λ ₀ × 0.135λ ₀ at the lowest resonant frequency. A maximal gain of 8.26 dBi, a low Specific Absorption Rate (SAR) of 0.0528 W/kg, and a high FBR of 33.85 dB at 4.1 GHz are key performance characteristics. VSWR values below 2 in both bands indicate exceptional impedance matching. Experimental validation using a Vector Network Analyzer (VNA) and an anechoic chamber confirms the modeling results. The proposed antenna, owing to its low SAR and wideband performance, is suitable for body‐centric wireless systems operating in standard frequency bands such as ISM, Wi‐Fi 6E, and C‐band.

This study investigates the design and performance of millimeter-wave (mm-Wave) Multiple-Input Multiple-Output (MIMO) antennas for fifth-generation (5G) applications, with a particular focus on the consequences of incorporating a ring resonator within the antenna system. This study compares two design variations, one with a ring resonator, and one without to assess their impact on enhancing the antenna's performance characteristics. The research employs five machine learning algorithms, namely, Decision Tree, Random Forest, K-Nearest Neighbors (KNN), XG-Boost, and Gradient Boosting Regressor (GBR), to estimate return loss. Among these, the Random Forest algorithm demonstrates superior performance in terms of accuracy, Mean Squared Error (MSE), Mean Absolute Percentage Error (MAPE), Mean Absolute Error (MAE), and R-squared metrics. The proposed MIMO antenna system shows better performance in Envelope Correlation Coefficient (ECC), Diversity Gain (DG), Channel Capacity Loss (CCL) and Total Active Reflection Coefficient (TARC). The results indicate that including a ring resonator in the antenna design significantly improves the antenna's performance, and machine learning algorithms, particularly Random Forest, can effectively predict and optimize critical parameters for antenna design in 5G applications.

The wireless and mobile communication industries have developed over the past decade. Thus, a Microstrip antenna is necessary for proficient communication. It defines a circular Microstrip antenna that is well-organized, dual band and low cost An FR-4 substrate material (ξr = 4.4) is used to mount a circular patch. In order to allow dual band operation, the circular patch retains E shaped circular slot. Based on High Frequency Structural Simulation (HFSS) tool, an antenna is considered and replicated using Finite Element Method (FEM). An antenna designed to operate dual band at 3.77 GHz and 5.14 GHz showed a higher bandwidth. The proposed dual band circular shaped antenna has higher Gain and Enhanced Bandwidth and suitable for IoT applications.