PP-based 24 GHz wearable antenna

Abstract

A wearable millimetre-wave radar antenna operating in 24.05–24.25 GHz for imaging applications in collision avoidance to assist visually impaired people is presented. Non-uniform excitation for the series end-fed 1 × 10 array antenna is optimized in simulation achieving a modified Dolph–Chebyshev distribution, which provides improved performance in terms of beam width, Side-lobe level and Gain. Commercial RO3003 and eco-friendly polypropylene (PP) are considered as substrates for comparison purposes, being the PP electromagnetically characterized for the first time at such high frequencies. Consistent agreement between simulation and measurement results is achieved for antenna prototypes on both dielectrics. The impedance matching bandwidth is analysed for the antenna on PP also under bent conditions. The overall size of the compact, low-cost, eco-friendly and flexible antenna on PP is 98.68 × 14.4 × 0.52 mm3 and, according to literature survey, it overcomes the state of the art on wearable radar antennas at 24 GHz. Graphical Abstract: (Figure presented.)