A Comparative Study of Aerosol Jet Printing on Polyimide and Liquid Crystal Polymer Substrates for RF Applications

Aerosol jet printing has been emerging as an attractive circuit fabrication technique in flexible and wearable radio frequency (RF) electronics due to the capabilities it provides beyond conventional fabrication techniques. In this paper, the effect of AJP process parameters on the printability of transmission lines on Kapton and LCP was investigated in details. Better wettability for the used ink on LCP has contributed to better line definition. The effect of sintering temperature and laser sintering power on the conductivity of transmission lines on both substrates was also studied. Employing Laser sintering has increased the conductivity significantly: 30% versus 10% of the silver bulk conductivity. However, the adhesion of the laser sintered lines on Kapton was very weak where all the lines fell off the substrate. On the other hand, the adhesion of the laser sintered lines on LCP was very good and passed multiple times of the tape test.Mircostrip lines were designed and fabricated on both substrates. The insertion loss for lines on LCP is around 0.32 dB/mm while on the Kapton samples is around 0.38 dB/mm at 40 GHz.