This study aims to design a compact antenna structure suitable for implantable devices, with a broad frequency range covering various bands such as the Industrial Scientific and Medical band (868–868.6 MHz, 902–928 MHz, 5.725–5.875 GHz), the Wireless Medical Telemetry Service (WMTS) band, a subset of the unlicensed 3.5–4.5 GHz ultra-wideband (UWB) that is free of interference, and various Wi-Fi spectra (3.6 GHz, 4.9 GHz, 5 GHz, 5.9 GHz, 6 GHz). The antenna supports both low and high frequencies for efficient data transfer and is compatible with various communication technologies. The antenna features an asynchronous-meandered radiator, a parasitic patch, and an open-ended square ring-shaped ground plane. The antenna is deployed deep inside the muscle layer of a rectangular phantom below the skin and fat layer at a depth of 7 mm for numerical simulation. Furthermore, the antenna is deployed in a cylindrical phantom and bent to check the suitability for different organs. A prototype of the antenna is created, and its reflection coefficient and radiation patterns are measured in fresh pork tissue. The proposed antenna is considered a suitable candidate for implantable technology compared to other designs reported in the literature. It can be observed that the proposed antenna in this study has the smallest volume (75 mm³) and widest bandwidth (181.8% for 0.86 GHz, 9.58% for 1.43 GHz, and 285.7% for the UWB subset and Wi-Fi). It also has the highest gain (−26 dBi for ISM, −14 dBi for WMTS, and −14.2 dBi for UWB subset and Wi-Fi) compared to other antennas in the literature. In addition, the SAR values for the proposed antenna are well below the safety limits prescribed by IEEE Std C95.1-1999, with SAR values of 0.409 W/Kg for 0.8 GHz, 0.534 W/Kg for 1.43 GHz, 0.529 W/Kg for 3.5 GHz, and 0.665 W/Kg for 5.5 GHz when the applied input power is 10 mW. Overall, the proposed antenna in this study demonstrates superior performance compared to existing tri-band implantable antennas in terms of size, bandwidth, gain, and SAR values.

A compact multiple input multiple output (MIMO) antenna operating at 2.45 GHz industrial scientific and medical band is presented for wearable devices. Open-end slotting is used to miniaturize the antenna dimensions. Inverted U-shaped ground stub is incorporated to reduce mutual coupling. On-body performance is analyzed on a three-layered equivalent tissue phantom model. The wide bandwidth of 300 MHz and port isolation of 30 dB are obtained from measured results. The antenna shows the efficiency of 40% and directivity of 4.56 dBi when placed at a gap of “s” = 4 mm from the body. Broadside radiation pattern and low specific absorption rate make the antenna suitable for on-body communication. Further, diversity performance is measured in terms of envelope correlation coefficient (ECC), diversity gain (DG), and channel capacity loss (CCL). The value of ECC is 0.025, DG is 9.98 dB, and CCL is 0.12 bits/s/Hz at 2.45 GHz. Antenna robustness is examined by bending the structure at different radii along the x-axis and y-axis. Performance of the proposed structure is reliable with structural deformation.

Bio-telemetry is an advanced area of research that enables the transmission of biomedical parameters from human body to external monitoring device. Wearable antennas showing robust performance are attaining attention for RF bio-telemetry. A square ring shaped ground antenna with a truncated patch is investigated for dual mode, on-body and off-body communication. The proposed antenna structure is analyzed and optimized on a multilayered flat tissue phantom. Proposed design resonates at 2.6 GHz with |S11| -22 dB and at 5.2 GHz with |S11| -35 dB on the phantom gel. Wide bandwidth of 520 MHz (2.33-2.85 GHz) and 620 MHz (4.78-5.4 GHz) efficiently covers ISM, LTE and WLAN bands and enables the antenna to withstand frequency detuning due to different body postures. Antenna shows maximum radiation efficiency of 15% at 2.45 GHz band when placed close to the tissue. Low specific absorption rate (SAR) value of 0.459/0.523/0.303 W/Kg at 2.45/2.6/5.2 GHz ensures the tissue safety.

A wide band, dual radiator Multiple input multiple output (MIMO) antenna resonating at 2.4 GHz Industrial Scientific and Medical (ISM) band is designed and analysed for the body-centric wireless communication. Defected ground structure (DGS) is used to reduce the antenna size and to achieve wide bandwidth. Moreover, a decoupling slot is also etched in the ground plane to improve the port isolation. Proposed 2 × 1 array MIMO structure has occupied the volume of 90 × 40 × 0.8 mm³. Rectangular and cylindrical shaped multi-layered tissue models are used for simulation and pork tissue is used for the measurement of antenna performance. Broad 10-dB bandwidth of 1250/900 MHz, port isolation of 21/20 dB, gain of 5.53/5.07 dBi with, SAR value of 0.628/0.627 W/kg is achieved for the flat/deformed state of antenna. Results show that the proposed DGS-based antenna is reliable to operate on different tissue environment for body area network.

The most important technique for exposing early-stage breast cancer is terahertz imaging. It aids in lowering the number of breast cancer-related fatalities and enhancing the quality of life. An essential component of developing the THz imaging system for high-quality photos is choosing the right sensor. In this article, a wideband antenna for microwave imaging of breast tissue with an operating frequency of 30 GHz (107 GHz to 137 GHz) is constructed and analyzed. An aperture-coupled antenna with an optimized ground aperture is proposed and analyzed, which made it possible to obtain better and consistent impedance matching in the wideband spectrum. The variation of backscattered signal energy in body tissue is assessed with healthy breast tissue and in the presence of malignant cells. A significant difference in energy scattering is observed for both situations. The suggested antenna’s linear and stable time domain characteristics make it an appropriate component for THz imaging technology.