Low Profile Wideband Dual-Ring Slot Antenna for Biomedical Applications

In this study, a low-profile, co-planar waveguide (CPW) fed, wideband, and dual-ring slot antenna design for biomedical applications is proposed. The proposed antenna has a total area of 10 mm × 10 mm and a height of 0.4 mm, and is designed by using a thin and biocompatible FR4 epoxy (εr = 4.4) substrate to accomplish human body isolation and great flexibility obtained by implantation. This wideband antenna covers a large bandwidth of industrial scientific and medical (ISM) frequency band, including 902.8 MHz to 928 MHz, 1.395 GHz to 1.4 GHz, 1.427 GHz to 1.432 GHz, 2.4 GHz to 2.485 GHz, and above. The simulation results of return loss, voltage standing wave ratio (VSWR), impedance matching, gain, and radiation pattern of the proposed antenna are obtained through High Frequency Structure Simulator (HFSS) 14 software

Ultra-Thin Nona-Band Polarization Insensitive Metasurface for High-Quality Sensing, EMI-Shielding, and Antenna RCS Reduction

In this article, a nona-band metasurface with unit cell dimensions of 0.038λo×0.038λo×0.019λo is designed on a FR-4 substrate of 1.0mm thickness with 35µm copper cladding. In TE/TM mode, the absorbance is greater than 99% at the intended frequency bands (i.e., 5.76, 8.6, 12.68, 14.38, 17.05, 17.94, 19.20, 20.88, 22.62, and 23.62GHz), and its reflectivity is almost zero. Results indicated that the metasurface is found to extremely independent on the angles of polarization of the incident wave and the absorber is almost insensitive to the incident angle (0° – 90°) for TE/TM modes. The unit cell of metasurface is having negative permittivity, near zero permeability and negative refractive index at all intended bands which confirm exotic properties of the metasurface. The metasurface is having high quality-factor (Q = 72) at 5.76GHz frequency therefore, this metasurface is also useful for dielectric sensing application in intended bands.[1]The metasurface's unparalleled properties make it suitable for EMI shielding, sensing applications in the C, X, and Ku-bands, the reduction of mono-static RCS, the improvement of isolation in MIMO antennas, and the reduction of unintended noise produced by copper components used in satellite and RADAR communication.</p