Abstract
The article presents a miniaturized ultra-wideband (UWB) antenna tailored for modern defense and small satellite communication requirements. Designed and optimized using CST Microwave Studio, the antenna delivers superior electromagnetic performance across both Sub-6 GHz and millimeter-wave frequency ranges. Realized on an FR4 substrate with overall dimensions of 10 × 12 × 1.5 mm³, the prototype achieves an impressive operating bandwidth of 3.4-14 GHz, equivalent to an impedance bandwidth of 121.8%. The measured results highlight a peak gain of 4.56 dBi, a return loss of -28 dB, and a radiation efficiency of 82.9%, ensuring reliable performance over a broad spectrum. With an electrical size of 0.113λ × 0.136λ × 0.017λ, the proposed design demonstrates remarkable compactness while maintaining stable radiation patterns and high efficiency. These characteristics make the antenna a strong candidate for resilient, interference-resistant, and high-performance applications in defense systems and CubeSat missions.