2.5 GHz-range SAW propagation and reflection characteristics and application to passive electronic tag and matched filter

Surface acoustic waves have been applied in various electronic devices. A signal processing device using SAW is one of the important applications. The devices operating at higher frequencies should be developed. In this paper, 2.5 GHz-range SAW excitation, propagation and reflection characteristics are experimentally investigated. The attenuation of SAW on 128° Y-X LiNbO₃ is 0.0035 dB/λ and 0.026 dB/λ (with distributed reflector electrodes) at 2.5 GHz. SAW reflection coefficients of various types of electrode (conventional short and open type, IDT type, positive and negative reflection type and double IDT type operating at 3rd harmonics, etc.) are examined. The characteristics of the coded signal for the passive electronic tag using the distributed reflection electrodes show the good results. Time domain characteristics from frequency domain characteristics are experimentally and theoretically studied using inverse-Fourier transformation. The code signal intensities at time domain show around 50 dB insertion loss without matching condition. Also, matched filter devices using the above devices are obtained