Fast Time-Domain Synthesis of Full Radiation Characteristics of 3-D Curved Wire Antennas Based on Liénard–Wiechert Potential

This paper presents a novel fast time-domain synthesis approach of three-dimensional curved thin-wire antennas, to achieve desired full radiation characteristic. The thin antenna is modeled as a series of connected, electrically short segments, allowing for flexible designs of arbitrary shapes. Using Liénard-Wiechert potentials, the radiation fields of these segments are efficiently computed, facilitating both rapid analysis and synthesis. A comprehensive signal space analysis is introduced to account for amplitude variation and waveform distortion, ensuring mathematical rigor and geometric clarity. The proposed approach is validated with the design and implementation of a wideband unidirectional circularly polarized antenna. The antenna achieves an impedance bandwidth of 121.9%, a 3-dB axial ratio bandwidth of 121.1%, and a maximal realized gain of 12.5 dBic. In the time domain, it delivers a fidelity of 0.977, demonstrating its suitability for short-pulse applications. The approach also supports multi-objective optimization, enabling customized designs that balance amplitude, waveform, and polarization. This synthesis approach offers a versatile and efficient solution for impulse radio ultra-wideband technology.