A compact, flexible and transparent UWB bandpass filter with silver nanowires

The advent of ultra-wide band (UWB) technology has made bandpass filters omnipresent. Current approaches to designing bandpass filters cannot provide transparent and flexible bandpass filters to meet their increasing demands for various applications. In this new work, a flexible and transparent UWB bandpass filter with silver nanowires printed on flexible polyethylene terephthalate (PET) substrates is designed. The filter structure is formed by connecting three pairs of open-circuited rectangular stubs. Proper coupling of these stubs is used to obtain the desired UWB passband. The proposed design operating from 1.05 to 10.75 GHz with an extremely wide stopband up to 50 GHz and a rejection level of 11.4 dB is demonstrated in the measured results. Furthermore, it was observed that the measured results matched well with the simulated results. These improved results indicate that our design strategy will provide a way to design highly efficient flexible UWB filters. This flexible filter may serve as a potential candidate for increasing the flexibility of indoor electronic applications.