Aerosol-Printed Highly Conductive Ag Transmission Lines for Flexible Electronic Devices

We studied aerosol jet printing on flexible substrates for wearable and flexible electronic devices. First, we investigated the electrical conductivity of aerosol jet printed silver layers at different temperatures. An electrical conductivity up to 60% of bulk Ag was measured after sintering at 140 °C on a hot plate. Higher conductivities became possible with higher sinter temperatures. The printed ink showed a surprisingly high flexibility. Transmission lines were printed on flexible substrates [Kapton and Rogers liquid crystal polymer (LCP) foils], and the performance was measured up to 110 GHz. The coplanar waveguide transmission lines demonstrated insertion losses of 0.366 dB/mm for LCP and 0.546 dB/mm for Kapton foils at 110 GHz.