Miniaturized Ultra-Wideband microstrip antenna with triple band-notched characteristics at WiMAX/WLAN/X-band for medical applications

Abstract This research presents a compact Ultra-Wideband (UWB) microstrip patch antenna with triple band-notched characteristics for WiMAX, WLAN, and X − band applications. The antenna features a rectangular radiator with a trimmed base, a partially defective ground structure (DGS), and three nested ‘U’- and inverted -‘U’shaped slots. A DGS with complementary split-ring resonators (CSRRs) further enhances performance. With dimensions of 27.45 × 29.65 mm 2 on a 1.6 mm FR − 4 substrate, the antenna operates across the UWB range (Simulated: 2.71 − 10.87 GHz; Measured: 2.81 − 10.81 GHz) with VSWR < 2, except at the notch bands (3.414 − 3.869 GHz, 4.945 − 5.354 GHz, and 7.504 − 7.949 GHz), effectively rejecting interference from WiMAX (3.35 GHz), WLAN (5.05 GHz), and X − band (7.70 GHz). Performance evaluations include reflection coefficient, VSWR, gain, efficiency, and radiation pattern. The antenna achieves a peak gain of 3.6 dBi, a radiation efficiency of 90%, and an omnidirectional radiation pattern. Simulations over a human tissue phantom confirm Specific Absorption Rate (SAR) values below 1.6 W/kg for 1 g of tissue, ensuring compliance with safety standards for biomedical applications. The measured results closely match simulations, making this antenna a strong candidate for wearable and medical devices requiring reliable UWB performance while minimizing human exposure risks.