Inkjet-printed silver film on multilayer liquid crystal polymer for fabricating a miniature stub-loaded bandpass filter

• The lamination bonding process on multilayer LCP was established.
• Mechanical properties of silver film are studied.
• Microstructure and electrical characteristics of silver film are compared.
• Printed silver-based multilayer LCP band pass filter was developed.

In this study, the mechanical properties of silver film are studied using a nanoindentation test, dynamic bending test, and lamination bonding pressure test. The hardness and elastic modulus of silver film were approximately 1.08 and 88.5 GPa, respectively, which corresponds to those of bulk silver. Acceptable fatigue properties were obtained after 104 dynamic bending cycles. A lamination bonding pressure of 0.69 MPa and temperature of 270 °C were used to achieve multilayer liquid crystal polymer (LCP) technology. A miniature bandpass filter using inkjet printing technology on multilayer LCP was realized with a minimal S21 value of − 1.4 dB at 25 GHz. The results demonstrated the proposed design methodology and fabrication technique.