As a new type of passive wireless sensor, surface acoustic wave resonator has application potential in many occasions, but it depends on the direct effect of the object to be measured on the resonator itself. In order to expand the application range, the reactance sensitive element is utilized as one of the components of the impedance matching network, and the impedance-loaded resonator-type sensor based on the low-mismatch network is designed. The sensing principle and the implementation essence of the low-mismatch network are analyzed. Furthermore, the scheme including pre-bias device is proposed, which not only moves the resonant frequency of the resonator itself to the middle of the impedance measurement range, but also doubles the frequency sensitivity range. The low-mismatch network test circuit board is made and the theory is verified. Finally, the reasons for the deviation between the measurement and the theory are analyzed, and the improvement direction of the theoretical model is put forward.