Ultra-wideband printed monopole antenna with cardioid-shaped fractal geometry

This paper presents a compact ultra-wideband (UWB) printed monopole antenna based on fractal cardioid geometry, designed to operate over the 4–30 GHz frequency range. The proposed antenna is intended for multi-service wireless applications, including IoT, WLAN, WiMAX, and satellite communications, while also being suitable for RF energy harvesting systems. Driven by the increasing density of wireless devices and ambient electromagnetic radiation, modern antenna systems are required to efficiently cover multiple frequency bands with a single compact structure. To address these requirements, the proposed antenna employs a fractal cardioid-based radiating element enabling significant bandwidth enhancement without increasing antenna size. The antenna is fabricated on a low-cost FR-4 substrate and experimentally validated. The measured results show good agreement with the simulated results, confirming the robustness of the design. The antenna achieves $$S_{11}$$ below − 10dB across a wide portion of the SHF band, with stable radiation characteristics, gain up to 5 dBi, and efficiency up to 80%. In addition, the antenna exhibits favorable impedance characteristics suitable for direct integration in rectenna systems without requiring a matching network. Owing to its compact dimensions, electrically small profile, low cost, ultra-wideband performance, and experimentally verified reliability, the proposed antenna is suitable for integration into next-generation IoT devices, multi-band communication systems, and RF energy harvesting applications.