Experimental Study of the Acoustic-Electromagnetic Hybrid Filter at a Wide Temperature Range

The frequency response of the acoustic-electromagnetic hybrid filter and its building blocks, acoustic wave resonators, are characterized over the temperature range from 113 K to 433 K. Frequency shifts at the down and upper edges of the filtering passband are extracted, and the temperature coefficient of frequency (TCF) is calculated to quantify the temperature stability. The variation in insertion loss and performance invalidity are analyzed in relation to the loss mechanism and thermal robustness of the hybrid topology. Characterization of acoustic-electromagnetic hybrid filters and their acoustic building blocks is essential in designing wide bandwidth wireless communication systems that are applied to diverse harsh environment application scenarios. The results and discussion demonstrate the trade-off between the robustness and bandwidth of hybrid filters, the pros and cons of hybrid topology at extreme temperatures, and the direction of future work on thermal stability.