High-Contrast Low-Loss Antenna: A Novel Antenna for Efficient Into-Body Radiation

We present a biocompatible high-contrast low-loss antenna (HCLA) designed for efficient into-body radiation for applications as diverse as medical telemetry, sensing, and imaging. The HCLA is wearable with a compact size of 2.62 cm³ and operates across the 1 to 5 GHz bandwidth. The quasi-bowtie antenna is loaded with a high-contrast (i.e., alternating layers of high and low permittivity materials) and low-loss dielectric to improve directivity and gain into the biological tissues. Measurement results at 2.4 GHz are in good agreement with simulations and show 5.72 dB improvement in transmission loss over the most efficient into-body radiator reported in the past. At the high end of the frequency bandwidth, simulation results for two antennas placed across each other with tissue in between show ~12.5 dB improvement in transmission loss. The HCLA is fabricated with stable, low-loss materials that allow for repeatability and consistency in the fabrication process, thus, addressing limitations of the current state-of-the-art. It is also made from biocompatible materials that enable it to be placed directly on the skin for real-world implementation. In this paper, we discuss the operation principle and design of the HCLA, its transmission performance, radiation patterns, and specific absorption rate.