3-D Printed Surface-Mounted Ceramic Filters: Temperature Drift Effect on Coupling Parameters

This study investigates the impact of temperature on four 3D-printed Alumina bandpass filters. Thermal cycling tests from 23 to 80°C reveal a frequency shift of −766 to −554 kHz/°C, depending on the design. The spatial arrangement of coupling iris structures relative to the heat source affects the inter-resonator coupling factors and the bandwidth drift. The results show bandwidth variations of 42 to 55 kHz/°C and insertion loss changes from 0.004 to 0.006 dB/°C.