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In this study, an ultraminiaturized implantable antenna is developed for biotelemetry applications. It has triple-band characteristics in the industrial, scientific, and medical (ISM) bands of 902–928 MHz for data telemetry and 2400–2483.5 MHz for power-saving applications and midfield band (1824–1980 MHz) for wireless power transfer simultaneously. The size of the proposed antenna is 0.068 $\lambda _{g}\,\,\times0.048\,\,\lambda _{g}\,\,\times0.0036\,\,\lambda _{g}$ and it is the smallest size of any triple-band implantable antenna ever devised without using shortening vias. Such a compact size is achieved by meandering the shape of the radiating patch and adding open-ended ground slots. Unlike most miniaturized implantable antennas reported in the available literature, no shortening pin is used and this makes the fabrication of the antenna very easy. The bandwidths measured in minced pork muscles are 14% and 24% in the lower and upper ISM bands, respectively, and 12% in the midfield band. The maximum values of the realized gain of the proposed antenna obtained in the heterogeneous skin phantom at 915, 1900, and 2450 MHz are −27.2, −22.2, and −19.9 dBi, respectively. In addition, specific absorption rates (SARs) in the heterogeneous skin and muscle tissues at the three resonance frequencies are calculated and show compliance with the IEEE standards for ensuring human safety. Finally, the range of the biotelemetry link is evaluated by calculating the wireless communication link budget at data rates of 7 kb/s, 100 kb/s, and 10 Mb/s at resonance frequencies. [ABSTRACT FROM AUTHOR]

The detuning owing to the complex in-body operating scenarios, environmental factors, and circuitry of the implantable medical devices (IMDs) are the primary concerns in integrating implantable antennas with their corresponding systems. The wide bandwidth achievement for avoiding the detuning challenges is constrained by device specifications and antenna miniaturization. This study presents an ultra-miniaturized antenna of only 10.66 mm3 volume with an ultra-wide bandwidth of 3040 MHz (0.79–3.83 GHz) for a leadless pacemaker (LP). The proposed antenna encompasses the five important bands: ISM (868–868.6 MHz, 902–928 MHz, and 2.4–2.48 GHz), Wireless Medical Telemetry Service (WMTS) (1395–1400 MHz), and the midfield (1.45–1.6 GHz) bands. To consider a practical operating scenario, the antenna was integrated with a battery and controlling electronics of an LP. In a homogeneous heart phantom (HHP), the proposed antenna showed a higher gain of −28.7, −20.02, and −16.7 dBi at 915 MHz, 1.4 GHz, and 2.45 GHz, respectively. The specific absorption rate (SAR) evaluation in the heart of a realistic model guaranteed patient safety by satisfying the IEEE C95.1-2005 and C95.1-1999 guidelines. The antenna is experimentally validated through measurements in minced pork. The strength of the received signal in the measurements confirms a stable biotelemetric link of the proposed ultra-wideband (UWB) antenna with an external monitoring system. The results obtained through simulations and in vitro testing emphasized that the proposed ultra-miniaturized and UWB antenna could operate more efficiently in the heart, thus establishing itself as a suitable candidate for the LPs. [ABSTRACT FROM AUTHOR]

An efficient noninvasive system for simultaneous transmission of wireless power and data is vital for continuous human health monitoring. In this article, we present a self-tuned spiral-shaped antenna with dual-band characteristics operating at 920 MHz and 2.4 GHz for efficient wireless power transfer (WPT) and data telemetry, respectively. To avoid vision blockage, the proposed smart contact lens (SCL) dipole antenna comprises two symmetrical spiral arms with inner and outer diameters of 10 and 14 mm, respectively. The SCL antenna was printed on a thin flexible polyimide substrate with a biocompatible polydimethylsiloxane (PDMS) coating. The influence of dispersed dielectric properties of PDMS on SCL antenna performance was investigated. Furthermore, the antenna was combined with a miniaturized rectifier and a micro-LED to demonstrate wireless LED illumination on a saline-filled model head. The power transfer efficiency (PTE) as a function of eye movement in the form of a path gain was also investigated. In addition, the PTE across the distance variations from 10 to 30 mm was computed, and a −17.85 dB was achieved at a separation of 12 mm. A specific absorption rate analysis was performed to determine human eye safety under radio frequency exposure from the external transmitter and the results complied with the International Commission on Non-Ionizing Radiation Protection guidelines. Furthermore, a theoretical link power budget analysis was experimentally validated using software-defined radio. Measurements of s-parameters were noted through the use of a saline solution to mimic a realistic human eye and were found to have a reasonable correlation with the simulated results. [ABSTRACT FROM AUTHOR]