24-GHz Patch antenna array on cellulose-based materials for green wireless internet applications

A 24-GHz patch array antenna with integrated feeding network has been fabricated exploiting a multi-layer cellulose-based (i.e. paper) substrate. The adopted microstrip circuitry exploits a copper adhesive laminate that is shaped by a photo-lithographic process and transferred to the hosting substrate using a sacrificial layer. The multi-layer structure is obtained by stacking and gluing two layers of photo-paper with an interposed copper ground plane. The measurements show an input reflection coefficient of about -29 dB at the centre frequency, an operating bandwidth with S₁₁ ≤ -20 dB of 540 MHz and a gain of 7.4 dBi. The estimated radiation efficiency is 35%. The proposed design shows the feasibility of low-cost antenna systems for green wireless internet technology and applications up to the boundary between microwaves and millimetre-waves.