SAW impedance element filters towards 5 GHz

Surface acoustic wave (SAW) impedance element filter (IEF) prototypes operating in the 2 and 5 GHz ranges were designed, fabricated and characterized. The coupling-of-modes (COM) model was used for design. The patterning was carried out on 36° Y-cut LiTaO₃ substrates using direct-writing electron-beam lithography and the lift-off technique. The periodicity of the resonators in the filters for the 5 GHz regime was on the order of 400 nm. For the 2 GHz devices, with adjusted input parameters corresponding to the actual finger profile, the measured and modelled responses coincide in the passband. For the 5 GHz devices, despite the nonideal finger profile, the results obtained are similar with the exception of the higher insertion loss of the measured device (6.5 dB)