An ultra-wideband Vivaldi antenna development for brain microwave imaging

Area of Science:

• Electromagnetics and Applied Physics
• Biomedical Engineering
• Antenna Theory and Design

Background:

• Microwave imaging offers a non-ionizing approach for brain imaging.
• Existing antennas often lack the required bandwidth and performance for effective brain imaging.
• Development of specialized antennas is crucial for advancing microwave-based medical diagnostics.

Purpose of the Study:

• To design and analyze a compact, ultra-wideband (UWB) Vivaldi antenna for brain microwave imaging.
• To evaluate the antenna's performance in terms of bandwidth, gain, radiation patterns, and time-domain characteristics.
• To validate the antenna's suitability for high-fidelity microwave imaging through simulation and experimental measurements.

Main Methods:

• A tiny, rectangular, exponentially tapered slotted UWB Vivaldi antenna was designed with seven symmetric rectangular slots.
• Simulations were performed to determine impedance bandwidth (IBW), fractional bandwidth (FBW), and return loss (|S11|).
• Experimental measurements validated the antenna's performance, including IBW, FBW, gain, front-to-back ratio (FBR), and time-domain response (pulse distortion, group delay).

Main Results:

• The antenna achieved a simulated IBW of 1.35–5.50 GHz (121.17% FBW) and a measured IBW of 1.4–6.4 GHz (128.20% FBW).
• A peak gain of 9.99 dBi and an FBR exceeding 30 dB were recorded, indicating directional radiation.
• Time-domain analysis showed minimal pulse distortion and a group delay under one nanosecond, with a high fidelity factor of 96.26%.

Conclusions:

• The developed UWB Vivaldi antenna demonstrates excellent performance characteristics for brain microwave imaging.
• Both simulated and measured results confirm the antenna's efficacy and suitability for high-fidelity, non-invasive medical imaging.
• The antenna's compact size and wide bandwidth are significant advantages for practical implementation in brain imaging systems.