Publications

Microresonant impedance transformers

Olsson, Roy H.; Wojciechowski, Kenneth W.; Tuck, Melanie R.; Stevens, James E.

Widely applied to RF filtering, AlN microresonators offer the ability to perform additional functions such as impedance matching and single-ended-to- differential conversion. This paper reports microresonators capable of transforming the characteristic impedance from input to output over a wide range while performing low loss filtering. Microresonant transformer theory of operation and equivalent circuit models are presented and compared with measured 2 and 3-Port devices. Impedance transformation ratios as large as 18:1 are realized with insertion losses less than 5.8 dB, limited by parasitic shunt capacitance. These impedance transformers occupy less than 0.052 mm2, orders of magnitude smaller than competing technologies in the VHF and UHF frequency bands. ©2009 IEEE.