Miniaturization technique for a quasi-Yagi antenna using characteristic mode analysis

This study presents a miniaturization technique for quasi-Yagi antennas using characteristic mode analysis (CMA). Due to their long wavelength, L-band applications such as remote sensing and radars require large antennas, emphasizing the importance of research focused on miniaturization solutions. Quasi-Yagi antennas, known for their planar structure and wide bandwidth, are suitable for L-band applications but require effective miniaturization for practical use. Through CMA, the resonant behavior of the antenna reflector can be analyzed, enabling the design of a V-shaped reflector that minimizes size while maintaining performance. Furthermore, this approach reduces the reflector-driver spacing and enhances both bandwidth and front-to-back ratio (FBR). The proposed design achieves a 49.93% size reduction compared to conventional designs, with dimensions of 53 × 56 mm². The addition of a director further improves gain, achieving a peak realized gain of 5.25-6.46 dBi and an FBR exceeding 11 dB across the 1.59-2.14 GHz range. Unlike prior studies reliant on trial-and-error methods, this research establishes a theoretical foundation using CMA. The proposed design offers an innovative solution for compact, high-performance L-band antennas and is expected to contribute greatly to advancing quasi-Yagi antenna design methodologies.