Temperature dependence of a tunable phase shifter based on inkjet printing technology

This work adresses the temperature dependence of tunable components based on inkjet printed low temperature sintered Barium-Strontium-Titanate (BST) thick-film layers. To evaluate the temperature dependence, metal-insulator-metal (MIM) parallel-plate capacitors were fabricated and characterized over a temperature range between -60°C and 100°C. A relative capacitance shift below 8.3% was measured in the unbiased state and 1.4% in the biased state. To evaluate the impact of this shift, a phase shifter was fabricated and characterized within the same temperature range. Around 4.5 GHz a maximum figure of merit of 46.7°/dB was measured, having a 92.7° phase shift by applying 50V tuning voltage. The relative phase shift due to temperature is below 4.7%, which shows promising results for a wide temperature operation range.