E-shape metamaterials embedded implantable antenna for ISM-band biomedical applications

Abstract

This paper presents a compact antenna based on two different metamaterial resonators, the E-shape resonators and the interdigital resonators suitable for biomedical implant applications. The proposed antennas operate in the industrial, scientific, and medical (ISM) bands in the frequency band of 2.4-2.5 GHz. The integration of metamaterial (MTM) in the design leading to the reduce size of these antennas and gaining enhancement. The overall size of the proposed antennas is 𝟖 × 𝟕 × 𝟏. 𝟐𝟕𝐦𝐦 𝟑 . The implantable antennas contain two layers of the substrate; the lower layer comprises the MTM resonators and the upper, superstrate layer. To order to observe the exposure of electromagnetic energy to human tissues, the specific absorption rates (SARs) of the proposed antennas are also calculated in the layer model. The antennas are designed and simulated by the two software simulators CST and HFSS.

A metamaterial unit-cell based patch radiator for brain-machine interface technology

“…The proposed MTM is designed in CST through numerous numerical simulations, tailoring the arms of a U-shaped structure. This process is followed by adjustments to the reflection coefficient and transmission coefficient until the desired MTM characteristics are achieved through the Nicolson-Ross-Weir (NRW) approach [ [ 16 ]]. The tailoring process is carried out on a trial-and-error basis to attain the desired performance.…”

“…Generally, the Nicolson-Ross-Weir method is used to extract the permittivity ( ), permeability ( ) and refractive index ( of the metamaterial structure. Therefore, equations ((1), (2), (3)) are utilized for analysing the metamaterial properties of the unit cell [ [ 15 , 16 ]]. where transmission coefficient and reflection coefficient are denoted as , the wave number is represented as k = 2 /λ and substrate thickness is denoted as h.

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“…These structures exhibit negative effective permittivity and permeability values at specific frequencies, effectively enlarging the size of the radiating element beyond its physical dimensions and enhancing gain and directivity by manipulating electromagnetic wave propagation. Numerous works have explored this avenue [ [15] , [16] , [17] , [18] ], incorporating unit cell metamaterial structures on the antenna patch or ground to improve gain and directivity. For example, a gain enhancement of approximately 2 dB at 915 MHz and 1.5 dB at the 2450 MHz frequency band were observed when incorporating the metamaterial (MTM) into the antenna structure [ [ 17 ]].…”

A Miniaturized Enhanced Gain Wideband Metamaterial Loaded Planar Inverted F-L Implant Antenna

“…In the field of implantable antennas for biomedical applications, metamaterial-loaded antennas have also indeed found applications, [11][12][13][14][15]. Implantable antennas are very important and employed in many biomedical applications such as temperature monitoring, cancer detection, tumor detection, orthopedic monitoring, glucose monitoring, and digestive monitoring.…”

Electromagnetic metamaterials for biomedical applications: short review and trends

“…At the same time, Hilbert fractal structures on its ground have helped towards miniaturization [23]. Implantable and wearable antennas also incorporate metamaterial-inspired features to achieve extra miniaturization [29][30][31]. Metamaterial-inspired techniques have also been applied to improve the gain of various biomedical antennas or to reshape their radiation pattern to enhance directivity for breast and brain imaging applications [24,32,33].…”