Inkjet-printed miniaturized flexible UWB antenna with quad-mode switchable notch for wearable and high-density wireless electronics

Abstract Ultrawideband (UWB) antennas with switchable notch properties merge reconfigurability and spectral filtering to address interference challenges in modern wireless systems. However, existing designs often suffer from bulky rigid substrates, limited operating modes, and complex fabrication processes. This paper presents a miniaturized, inkjet-printed flexible UWB antenna with quad-mode reconfigurable notch capabilities. The antenna features a compact footprint of 16 mm × 18 mm × 0.12 mm on a flexible polyethylene terephthalate (PET) substrate. By integrating ‘C’- and ‘H’-shaped slots with two PIN diodes, it achieves four operational modes: full UWB (3.1–10.6 GHz), two single-notch modes (3.3–4.8 GHz or 7.5–8.6 GHz), and a dual-notch mode (3.3–4.7 GHz and 7.5–8.6 GHz) to suppress WiMAX, 5 G, Insat, and X-band interference. The inkjet-printed prototype exhibits stable radiation patterns (<6 dBi gain variation), rapid switching (<1 µ s), and robust bendability ( R y > 60 mm). Measured results align with simulations, confirming stable radiation efficiency (>60%), low cross-polarization, and minimal performance degradation under bending. These attributes validate its suitability for high-density wireless environments (e.g., WiMAX, 5 G) and wearable electronics, offering enhanced signal purity, ease of integration, and cost-effective fabrication.