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This paper reports on the successful fabrication of a multilayered hybrid printed circuit board (PCB) for applications in the consumer electronics products, medical technologies, and military equipment. The PCB was fabricated by screen-printing silver (Ag) flake ink, as metallization layer, and UV acrylic-based ink, as dielectric layer, on different substrates such as paper, polyethylene terephthalate, and glass. Traditional electronic components were attached onto the printed pads to create the multilayered hybrid PCB. The feasibility of the hybrid PCB was demonstrated by integrating an embedded microcontroller to drive an liquid-crystal display (160 × 100 pixels). In addition, the amount of the ink spreading after printing, the effect of bending on the printed lines, and the effect of the roughness of the substrates on the resistance of the printed lines was investigated. It was observed that the resistance of the lines increased by ≈1.8%, after 10 000 cycles of bending, and the lowest resistance of 1.06 was measured for the 600 μm printed lines on paper, which had a roughness of 0.175 μm. The advantage of fabricating PCBs on flexible substrates is the ability to fold and place the boards on nearly any platform or to conform to any irregular surface, whereas the additive properties of printing processes allow for a faster fabrication process, while simultaneously producing less material waste in comparison with the traditional subtractive processes. The results obtained show the promising potential of employing screen printing process for the fabrication of flexible and light-weight hybrid PCBs.

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In this work, a guided shear horizontal mode surface acoustic wave (SH-SAW) sensor, fabricated by patterning gold (Au) interdigitated electrodes (IDE) on a 64°YX-LiNbO 3 based piezoelectric substrate, was used for the detection of heavy metal compounds. A flow cell, with a reservoir volume of 3 µl, which employs inlet and outlet valves for the microfluidic chamber and polydimethylsiloxane (PDMS) based microfluidic channels, was also designed and fabricated using an acrylic material. The frequency based response of the SAW sensor towards varying concentrations of heavy metal compounds such as lead nitrate (PbNO 3) and cadmium nitrate (CdNO 3) were investigated. As the surface acoustic wave propagates on the substrate, between input and output IDEs, a shift in the resonant frequency of the SAW device was observed due to the change in velocity of the wave caused by the varying concentrations of the test analytes. The results obtained demonstrated the capability of the system to detect picomolar level concentrations. The response of the SAW sensor is analyzed and presented in this paper.

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