A Compact Size Implantable Antenna for Bio-medical Applications

Abstract

Implantable antennas play a vital role in implantable sensors and medical devices. In this paper, we present the design of a compact size implantable antenna for biomedical applications. The antenna is designed to operate in ISM band at 915 MHz and the overall size of the antenna is 4×4×0.3 mm 3. A shorting pin is used to lower the operating frequency of the antenna. For excitation purpose a 50-ohm coaxial cable is used in the design. A superstrate layer is placed on the patch to prevent the direct contact between the radiating patch and body tissues. The antenna is simulated in skin layer model. The designed antenna demonstrates a gain of 3.22 dBi while having a-10 dB bandwidth of 240 MHz with good radiation characteristics at 915 MHz. The simulated results show that this antenna is an excellent candidate for implantable applications.

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

“…Since the FR-4 substrate is not biocompatible, a very thin (0.05 mm) layer of polyamide superstrate with a relative permittivity ( ) of 4.3 and a loss tangent (tanδ) of 0.004 is used as biocompatible material to encapsulate the E-shaped patch and ground of the antenna, which helps to keep away the brain tissue from short circuiting. Due to its availability in different thicknesses and consistency at high temperatures, polyamide superstrate has been widely considered in numerous studies [ 3 , 14 , 26 , 27 ]. Therefore, the total antenna dimension is 20 × 20 × 1.6 (0.338 × 0.338 × 0.027 ).…”

“…In designing antennas for BMI applications, several specific criteria must be taken into account, including antenna miniaturization, high bandwidth, substantial gain, low specific absorption rate (SAR), optimal link budget, and most importantly, the antenna needs to be operated in a dedicated frequency band. Commonly employed frequency bands for implantable antennas are the Medical Implant Communications Services (MICS) band (402–406 MHz) and the Industrial, Scientific, and Medical (ISM) bands, encompassing ranges such as 433–434 MHz, 868–868 MHz, 902–928 MHz, and 2.4–2.4835 MHz [ [1] , [2] , [3] , [4] ]. Among these, the high-frequency ISM band (2.4 GHz) is preferred for a high-speed wireless link between the internal neural recording unit and the external unit for processing and decoding the neural activities [ [ 5 ]].…”

“…Biocompatible superstrates like Teflon, Alumina, Zirconia, PEEK, and MACOR can be used to ensure tissue safety [ [ 4 ]]. A thin (0.05 mm) layer of polyamide ( = 4.3 and tan δ = 0.004) superstrate can be employed to address biocompatibility issues [ [ 3 ]]. Additionally, to comply with safety standards, it is also vital to keep the specific absorption rate (SAR) within allowable limits regulated by IEEE C95.1–1999 and IEEE C95.1–2005 [ [ 2 , 9 ]].…”

A Compact Size Capacitive Load Dual Band Planar Inverted-F Implant Antenna for Biomedical Services

“…Several techniques are used for antenna miniaturization purposes: in [1][2][3], substrate and superstrate with a high dielectric constant were used to minimize the antenna size. In [4][5][6][7][8][9], a shortcircuited pin was inserted between the radiating conductor and the ground for antenna size miniaturization. Another technique is patch meandering used for antenna size reduction, [10][11][12][13][14][15].…”