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This paper presents an ultra-miniaturized skin implantable Multiple Input Multiple Output (MIMO) antenna for biotelemetry in the Industrial, Scientific, and Medical (ISM) band (2.4–2.48 GHz). The two-element configuration exhibits a compact planar volume of 4.5 × 6.2 × 0.25 mm³, with an edge-to-edge distance of 0.8 mm and a 75.85 % size reduction. Fabricated on a 0.25 mm thick Roger 10.2LM high permittivity substrate, the antenna achieves a Fractional Bandwidth (FBW) of 9.27 % and a realized gain of −28.2 dBi, with over 24.3 dB isolation across the entire band. Experimental results in multilayer animal tissue aligned well with simulations. Specific Absorption Rate (SAR) analysis at 1 W input power showed values of 848 W/kg (1-g) and 88.46 W/kg (10-g), yielding allowable input powers of 3.77 mW and 45.2 mW, respectively, adhering to international safety guidelines. The 2 × 2 element antenna demonstrated efficient communication over 7 m with a data rate of 78 Mbps/s. Multiple Input Multiple Output channel analysis revealed a Channel Capacity of 10.8 bps/Hz at a 20 dB SNR, nearly double that of an ideal Single Input Single Output system, making it suitable for high data rate skin-implantable applications. [ABSTRACT FROM AUTHOR]

The integration of health monitoring and wearable antenna technologies has enhanced patient assessment and the provision of healthcare. Traditional health monitoring methods have evoked a surge in interest toward embroidered antennas as a viable solution for constant physiological monitoring in a noninvasive way. This study examines the performance of an embroidered wearable textile (EWT) antenna intended for breathing rate applications. The antenna is seamlessly integrated into a commercially available T‐shirt, extending the confines of "smart" textiles. The compact (45 mm × 26 mm) EWT antenna operates in 2.4 and 5.8 GHz with gains of 2.07 and 5.85 dBi, respectively. Crumpling and stretching analysis have also been investigated to ensure antenna's mechanical stability and reliability. Subsequently a specific absorption rate analysis has also been performed to quantify the radiation within specified limits. [ABSTRACT FROM AUTHOR]

This article presents a compact implantable antenna for biomedical use in the ISM band (2.4–2.48 GHz). The antenna is designed with Roger RT/duroid 6010.2LM high permittivity substrate of thickness 0.25 mm, and feed with a 50 Ω co-axial feed. A hybrid-loop resonator slot structure and C & I-shaped slots in the radiating patch has enabled the antenna to work in the ISM band. Via less ground makes this design simple, easier to fabricate, and a suitable candidate for implantable application. The proposed antenna occupies a small volume of 0.0984 λ0 × 0.082 λ0 × 0.00468 λ0 and retained 152 MHz bandwidth (2.4077–2.5599 GHz with FBW 7.64 %) with a maximum gain of −22 dBi where λ0 is guided wavelength. The projected antenna has good performance in the multi-layer tissue model, male human head voxel model, frequency-dependent skin model, and in muscle phantom by maintaining a minimum −20 dB return-loss in the ISM band. The proposed antenna's Device Integration using a frequency-dependent skin phantom was performed and the results are well-suited for biomedical applications in the ISM band. The bare antenna was used to study the Specific Absorption Rate (SAR) in the human scalp. Where for 1 g and 10 g tissues the investigated results are 626.05 W/kg and 84.4 W/kg for an input power of 1 W, however the input power is limited to maximum 2.55 mW (for 1 g tissue) and 23.56 mW (for 10 g tissue) to comply with IEEE SAR guidelines. The qualities of the manufactured antenna are verified in a skin-imitating gel and animal tissue that exhibits good agreement with the simulation outcomes. [ABSTRACT FROM AUTHOR]

Summary: In this communication, an asymmetric co‐planar waveguide (ACPW)–fed composite right–left‐handed transmission line (CRLH‐TL)–based frequency band and polarization reconfigurable antenna (RA) is presented. The reconfigurability is achieved by using a PIN diode. When the diode is in OFF state, meander line works as part of ground. Hence, the antenna is like a circular patch antenna working at 5.15 GHz. In the ON state, the antenna works as a CRLH‐TL‐based antenna with an additional lower band resonating at 2.45 GHz. The antenna also has circular polarization (CP) property. The lower 2.4 GHz band is covering for IEEE 802.11 b/g/n/ax/be applications, whereas the higher band is covering the WiFi bands of IEEE 802.11a/h/n/ac/ax/be applications with CP radiation (upper band). This antenna is effective in a scattering environment such as in urban areas and indoor communication. [ABSTRACT FROM AUTHOR]

This article proposes a compact dual-band circular-shaped implantable antenna for scalp and skin implantation applications. The proposed antenna covers the 1.395-1.432 GHz Wireless Medical Telemetry Service (WMTS) band and 2.4-2.48 GHz Industrial, Scientific, and Medical (ISM) band with a compact volume of 0.000001730. The antenna maintains a realized peak gain of -24:5 dB and -20:6 dB, respectively, at 1.43 GHz and 2.44 GHz. Moreover, the gain pattern of the antenna is in the off-body direction which is a desirable feature for implantable scenario. It also depicts stable responses under different implantation scenarios. Moreover, the via free configuration is an advantageous feature of the proposed antenna in the context of fabrication complexity. Furthermore, a holistic design approach is considered with integrated components for device-level architecture. The resonance behavior of the proposed antenna structure is also analyzed by developing a conceptual equivalent circuit model. The evaluated specific absorption rate (SAR) complies with the regulated human safety standard. The biotelemetry link capability is also evaluated through the link margin (LM) calculation of the proposed antenna and is able to establish a communication link at a range of 4.5m distance. [ABSTRACT FROM AUTHOR]

A compact wideband multiple-input multiple-output (MIMO) antenna for body-centric communication is presented in this article. Initially, an electric field-driven LC metamaterial resonator inspired monopole antenna is developed that exhibits 122.19 % (1.28–5.30 GHz) bandwidth covering 2.4 GHz WLAN and 3.5 GHz WiMAX application bands. Thereafter, the MIMO antenna is proposed, and a pair of meander line structure as a wideband decoupling network is introduced on the ground plane to reduce the inter-element coupling. The proposed antenna holds a reduced mutual coupling and low envelope correlation coefficient over the wideband. To explain the wideband antenna response and its decoupling mechanism, a circuit model analysis is incorporated. Moreover, the proposed antenna demonstrates a robust performance under complex bending and crumpling conditions with an acceptable specific absorption rate (SAR <1.6) during the on-body conditions. Besides, a high data rate link-margin analysis makes the antenna suitable for wireless biotelemetry. [ABSTRACT FROM AUTHOR]

ABSTRACT The article explores a quad‐port compact (56 × 56 × 1.5 mm3) multiple‐input multiple‐output (MIMO) antenna developed on a colored resin fiber material encompassing enhanced isolation for wideband applications. The design antenna configuration incorporates four ground stubs positioned among antenna pairs on the upper section of the substrate and eight rectangular‐shaped ground slots to enhance antenna isolation. The antenna functions over a broad spectral range from 4.21 to 10.95 GHz, providing coverage for WLAN (5.15–5.35 GHz/5.725–5.825 GHz), C band uplink (5.925–6.425 GHz), downlink defense (7.2–7.7 GHz), and ITU band (8–8.5 GHz), with 88.91% fractional bandwidth. The antenna design ensures exceptional isolation, exceeding 21 dB among orthogonal antennas and 25 dB between oppositely placed antennas across the entire functioning bandwidth. Across the working band, the antenna showcases favorable diversity characteristics, including a lower envelope correlation coefficient (ECC < 0.085), higher diversity gain (DG > 9.95 dB), minimal channel capacity loss (< 0.39 bits/s/Hz), and negligible magnitude variation in mean effective gain among the antenna ports (< 0.1 dB). The acquired total active reflection (TARC) curve exhibits the antenna's robust resonance features over the application band and commendable time domain properties in the active spectral region. The findings of the simulation and measurements revealed a close alignment. [ABSTRACT FROM AUTHOR]