Development of a Compact Planar Antenna with Multi-Resonant Geometry for Broadband CubeSat Applications

This article presents the design and analysis of a Compact Planar Antenna with Multi-Resonant Geometry for Broadband CubeSat Applications. The antenna features a dual-layer architecture comprising a front semi-circular radiator with strategically positioned circular and rectangular slots, and a complex ground plane etched with complementary geometries to enhance performance. The optimized geometry, with key dimensions such as an overall size of 15 mm × 15 mm × 1.5 mm, enables a wide impedance bandwidth ranging from 2.9 GHz to 11.6 GHz. The impedance bandwidth of the radiator is 120%, with an electrical size of 0.14λ×0.14λ×0.014λ. Confirmed through both simulation and measurement using a VNA in an anechoic chamber, the gain performance increases steadily with frequency, reaching a peak of 4.2 dBi at 9.2 GHz, while maintaining a stable gain above 3 dBi between 3.8 GHz and 10.1 GHz. Radiation efficiency peaks at 87% around 5.6 GHz and remains above 75% within the mid-band range (4–8 GHz), indicating highly effective power radiation and minimal losses. Surface current and 3D radiation pattern analysis show efficient and focused radiation behavior at 6 and 9 GHz, supporting its suitability for wideband radar and secure communication applications.