★ A SPUDT structure achieving low IL and miniaturization wavelet transform device. ★ Three experimental devices are designed and measured for three different scales. ★ Better approximate to the ideal FR by the withdrawal and overlap weighting. ★ The novel method is fit for an arbitrary scale dyadic wavelet transform processor.
In this paper, we propose a low insertion loss and miniaturization wavelet transform and inverse transform processor using surface acoustic wave (SAW) devices. The new SAW wavelet transform devices (WTDs) use the structure with two electrode-widths-controlled (EWC) single phase unidirectional transducers (SPUDT–SPUDT). This structure consists of the input withdrawal weighting interdigital transducer (IDT) and the output overlap weighting IDT. Three experimental devices for different scales 2−1, 2−2, and 2−3 are designed and measured. The minimum insertion loss of the three devices reaches 5.49 dB, 4.81 dB, and 5.38 dB respectively which are lower than the early results. Both the electrode width and the number of electrode pairs are reduced, thus making the three devices much smaller than the early devices. Therefore, the method described in this paper is suitable for implementing an arbitrary multi-scale low insertion loss and miniaturization wavelet transform and inverse transform processor using SAW devices.