Design and Simulation of a 2.45GHz Compact and Wearable Microstrip Patch Antenna with Human Phantom Integration for Medical Applications

Abstract

Wireless body area networks (WBANs) play a growing role in modern healthcare, especially for continuous monitoring devices such as ECG sensors, heart rate trackers, and glucose monitors. A key challenge in these systems is designing antennas that are compact, efficient, and reliable when placed close to the human body.In this work, a rectangular microstrip patch antenna is designed for wearable medical applications, operating at 2.45?GHz. The antenna is built on a Rogers RT/duroid 5880 substrate and fed with a microstrip line to maintain a simple, planar structure. The design and optimization were carried out in ANSYS HFSS, with parameters such as patch dimensions, feed position, and substrate properties carefully tuned.To evaluate realistic performance, a three layer human tissue phantom model (skin, fat, and muscle) was included in the simulations. The antenna achieves resonance at 2.45?GHz with return loss below –10?dB, VSWR under 2, and a stable radiation pattern. The specific absorption rate (SAR) remains within FCC safety limits.Compared to textile based designs, the proposed antenna offers better impedance matching, compact size, and stable performance under body loading conditions. These results show that the antenna is suitable for integration into wearable healthcare devices.

Introduction

This work focuses on the design and simulation of a wearable microstrip patch antenna for Wireless Body Area Networks (WBANs) operating at the 2.45 GHz ISM band, commonly used in medical monitoring systems such as ECG, glucose tracking, and heart-rate sensing.

Background

WBAN devices require antennas that are compact, flexible, low-power, and safe for long-term skin contact. However, human tissue causes challenges such as signal loss, detuning, and increased SAR. To address this, microstrip patch antennas are preferred due to their low profile and ease of fabrication.

Design Approach

• A rectangular microstrip patch antenna is designed using Rogers RT/duroid 5880 substrate for low loss and high efficiency.
• A microstrip line feed is used for impedance matching.
• The antenna is optimized for:
  • Resonance at 2.45 GHz
  • VSWR < 2
  • Compact size (~70 × 70 mm²)
• A three-layer human phantom model (skin, fat, muscle) is used to simulate real on-body conditions.
• Design and optimization are performed using ANSYS HFSS with parametric tuning and full-wave simulation.

Theory and Operation

The antenna operates in TM?? mode, where fringing fields at the patch edges generate radiation. Wearable constraints include size limits, bending tolerance, and strict SAR safety (<1.6 W/kg).

Literature Review

Previous studies show a trade-off:

• Textile/flexible antennas → good comfort but lower efficiency and gain
• Rigid substrates → better performance but less wearable

Existing designs often lack full integration of high-performance substrates, phantom modeling, and optimized compact design.

Proposed Contribution

• Uses Rogers 5880 substrate for improved efficiency
• Includes full human-body phantom simulation
• Performs HFSS-based optimization
• Achieves balanced performance between safety, size, and signal quality

Results

Simulation results show:

• Resonant frequency: 2.456 GHz
• Return loss: –24.5 dB (excellent matching)
• VSWR: 1.13 (near ideal)
• Bandwidth: 2.41–2.49 GHz
• Gain: –4.03 dB (acceptable for wearable safety-focused design)
• SAR within safe limits

Conclusion

This work presented the design and simulation of a compact 2.45?GHz wearable microstrip patch antenna using the Rogers RT/duroid 5880 substrate, with full integration of a three layer human phantom model. The antenna achieved excellent impedance matching, demonstrated by a deep return loss of –24.6?dB and a VSWR close to unity. Although the gain was modest (–4.03?dB), the radiation pattern confirmed forward directed energy with minimal side lobes, ensuring safe and efficient operation near the human body. SAR analysis further validated compliance with international safety limits, with average absorption well below thresholds. Compared to earlier textile based designs, the proposed antenna offers superior matching, reduced size, and reliable performance under body loading conditions, making it highly suitable for wireless body area networks (WBANs). Minor frequency shifts observed during phantom testing were compensated through parametric tuning, confirming robustness for real world deployment.

References

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Copyright

Copyright © 2026 Dr. K. Ashok Kumar, A. Gopinadh, A. Yashraj, P. Vijayendra Babu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.