To achieve fully flexible microwave devices, we investigated flexible polymers in terms of chemical, mechanical, and electrical properties. Moreover, the fabrication techniques for polymer-based microwave devices have been developed to address chemical adhesion and demolding issues. Finally, based on formulated criteria, we have developed recipes for low-loss (0.001), low-Dk (1.73) flexible dielectric materials and applied them to the microstrip and CPW transmission lines. The microstrip and CPW lines’ transmission loss is as low as 0.065 and 0.034 dB/cm at 2.5 GHz, respectively. The effects of various materials on microwave performance have been analyzed, from which we show acceptable limits for fully flexible microwave devices in S and L bands. The proposed molding process allows us to step out from 2D PCB designs and build 3D structures or hybrid PCB-3D components with a certain freedom in material properties. Additionally, the new material exhibits unique mechanical properties, which extends the material application to other fields. This work demonstrates that polymer-based flexible microwave electronics can have a competitive performance compared to rigid PCB technology. Additionally, it has been found that the polymer-based devices have significant performance improvements at elevated temperatures, which can be exploited in a high-temperature application.
