Design of Implantable Rectangular Spiral Antenna for Wireless Biotelemetry in the MICS Band

Abstract

For this study, we designed an implantable rectangular spiral antenna for medical biotelemetry in the Medical Implant Communications Service band (402 MHz to 405 MHz). The designed antenna has a U-shaped loop for impedance matching. The antenna impedance is easily adjusted by controlling the shape and length of the Ushaped loop. Significant design parameters were studied to understand their effects on the antenna performance. To verify the potential of the antenna for the desired applications, we fabricated a prototype and measured its performance in terms of the resonant characteristics and gain radiation patterns of the antenna. In the testing phase, the prototype antenna was embedded in human skin tissue-emulating gel, which was developed to simulate a real operation environment. The measured resonant characteristics show good agreement with the simulations, and the -10 dB frequency band is within the range of 398 MHz to 420 MHz. The antenna exhibits a maximum gain of -22.26 dBi and an antenna efficiency of 0.215%.

Review on Medical Implantable Antenna Technology and Imminent Research Challenges

“…A spiral shape radiating patch is a useful antenna dimension miniaturization technique employed in [ 29 , 45 , 46 , 47 , 48 , 49 ]. Figure 9 a illustrates a spiral shape implant antenna operated at 225–427 MHz with an equivalent homogeneous body model.…”

“…The spiral shape helps to miniaturize the antenna dimensions to 17 × 17 × 18 mm 3 compared with other antennas given in [ 29 ]. Two spiral shape implant antennas to occupy a small area of 6 × 5 × 0.3 mm 3 [ 45 ] and 20 × 10 × 1.63 mm 3 [ 46 ] operated at 2.4 GHz and 405 MHz, respectively are shown in Figure 9 b,c. Several miniaturized dimensions with the spiral shape Complementary Split Ring Resonator (CSRR)-loaded implant antenna was reported in [ 47 , 48 , 49 ] for MICS applications.…”

A dual‐band implantable antenna with wide‐band characteristics at MICS and ISM bands

“…In this respect, many techniques have been adopted by researchers to achieve good results of downsizing. Among the used techniques, the use of high‐dielectric substrates, the inclusion of shorting pins, and the patch stacking extend the length of the current path, and meandering the radiating patch lengthens the current‐flow path …”

Integration of Resonant Coil for Wireless Power Transfer and Implantable Antenna for Signal Transfer

“…For wireless communications with implanted units, the medical implant communication service (MICS) band (402-405 MHz) is recommended by the Federal Communications Commission (FCC). An implantable antenna works in human or animal body and ensures the wireless communications, and many researches on the implantable antenna design have also been carried out [1][2][3][4][5][6][7][8][9]. Unlike typical antennas used in the air, the implantable antenna should satisfy various requirements and constraints such as antenna shape, biocompatibility, miniaturization, and broad bandwidth.…”

“…The well-known antenna minimization technique is to use the high-permittivity substrates (e.g., Rogers 3010/3210 with = 10.2), which shorten the effective wavelength. In the structural aspect, the dipole with spiral arms [1], meandered planar inverted-F antenna (PIFA) [3], and spiral PIFA [4] has been designed for this purpose. Additionally, the extended current path using slots or notches on the radiating patch [5] and the open-end slot antenna with a meandered slot on the top metal [6] are also suggested.…”