Screen-Printed Flexible Bandstop Filter on Polyethylene Terephthalate Substrate Based on Ag Nanoparticles

We present a low-power, cost-effective, highly reproducible, and disposable bandstop filter by employing high-throughput screen-printing technology. We apply large-scale printing strategies using silver-nanoparticle-based ink for the metallization of conductive wires to fabricate a bandstop filter on a polyethylene terephthalate (PET) substrate. The filter exhibits an attenuation pole at 4.35 GHz with excellent in-and-out band characteristics. These characteristics reflect a rejection depth that is better than -25 dB with a return loss of -0.75 dB at the normal orientation of the PET substrate. In addition, the filter characteristics are observed at various bending angles (0 degrees, 10 degrees, and 20 degrees) of the PET substrate with an excellent relative standard deviation of less than 0.5%. These results confirm the accuracy, reproducibility, and independence of the resonance frequency. This screen-printing technology for well-defined nanostructures is more favorable than other complex photolithographic processes because it overcomes signal losses due to uneven surface distributions and thereby reveals a homogeneous distribution. Moreover, the proposed methodology enables incremental steps in the process of producing highly flexible and cost-effective printed-electronic radio devices.