Design of Miniaturized Antipodal Vivaldi Antennas for Wideband Microwave Imaging of the Head

Many wideband applications, e.g., microwave imaging of the head, require low-frequency (~1–6 GHz) operation using small antennas. Vivaldi antennas are extensively used in multifarious applications; however, physical dimensions antenna become very large for covering bands. Hence, miniaturization antennas, while maintaining proper matching and radiation characteristics, is essential these applications. In this work, two miniaturized proposed, several techniques presented reducing size without need being immersed into any liquid, desired performance. The novelty designs lies use half-cut superstrates, which help achieving with end-fire radiation. Two prototype fabricated, performances analyzed from both simulation measurement results. show an FBW 45.26% 95.9% a gain ~1.9–5.2 dB ~1.5–5.5 dB, respectively, having efficiency above 80% within resonant bandwidth. A comparison proposed other state-of-the-art included to demonstrate viability performance comparatively dimensions.