# Compact AMC-Backed Flexible UHF RFID Tag Antenna for On-Body Biomedical Applications

## TL;DR

This paper introduces a compact, flexible RFID antenna designed for on-body biomedical applications, offering improved performance and reduced health risks.

## Contribution

A novel AMC-backed RFID tag antenna with a 50% size reduction and enhanced performance for biomedical use.

## Key findings

- The AMC metasurface design achieves a 50% size reduction and ultra-compact footprint (0.0246 λ²).
- The AMC shielding layer increases gain by ~13 dB and reduces SAR by over an order of magnitude.

## Abstract

What are the main findings?
A miniaturized AMC metasurface utilizing meandered Jerusalem-cross and interdigitated comb-like features was developed, achieving a 50% size reduction and an ultra-compact footprint (0.0246 λ2) compared to conventional unit cell geometries.The integration of the AMC shielding layer results in a substantial gain enhancement of approximately 13 dB and a reduction in SAR values by more than an order of magnitude compared to standalone tags on the human body.

A miniaturized AMC metasurface utilizing meandered Jerusalem-cross and interdigitated comb-like features was developed, achieving a 50% size reduction and an ultra-compact footprint (0.0246 λ2) compared to conventional unit cell geometries.

The integration of the AMC shielding layer results in a substantial gain enhancement of approximately 13 dB and a reduction in SAR values by more than an order of magnitude compared to standalone tags on the human body.

What are the implications of the main findings?
The use of a high-permittivity, silicon-doped biocompatible substrate enables a flexible and low-profile design (2.23 mm) suitable for epidermal sensing of physiological parameters such as pH, temperature, and skin impedance.The design’s robust platform tolerance and stability under bending ensure reliable long-range communication and operational integrity across diverse anatomical regions and dynamic wearable environments.

The use of a high-permittivity, silicon-doped biocompatible substrate enables a flexible and low-profile design (2.23 mm) suitable for epidermal sensing of physiological parameters such as pH, temperature, and skin impedance.

The design’s robust platform tolerance and stability under bending ensure reliable long-range communication and operational integrity across diverse anatomical regions and dynamic wearable environments.

This paper presents the design, modeling, and numerical validation of a compact artificial magnetic conductor (AMC)–backed flexible UHF RFID tag antenna intended for on-body biomedical and wearable sensing applications. Human tissue proximity typically causes severe detuning, radiation efficiency degradation, and increased specific absorption rate (SAR) for conventional RFID tag antennas. To address these limitations, a miniaturized AMC metasurface based on a modified Jerusalem-cross geometry with meandered and interdigitated features is developed on a high-permittivity biocompatible substrate using CST Studio Software (2025). Full-wave simulations demonstrate that the proposed design, with an ultra-compact footprint of 0.0246 λ2 (32.12 mm × 64.24 mm), functions as an effective shielding element, significantly enhancing the tag antenna gain and reading range by an order of magnitude compared to conventional on-body tags, while simultaneously reducing backward radiation and SAR. The antenna demonstrates robust platform tolerance and excellent isolation from the human body, ensuring high reliability. Fabricated on a thin, flexible, biocompatible, silicon-doped dielectric substrate, this device also functions as an epidermal antenna for on-skin health parameter sampling. This research paves the way for advanced, non-invasive wearable medical devices with superior performance.