In this paper, a dual band resonator using open-loop stub-loaded resonator is studied. By the characteristics of even/odd modes, the two resonant frequencies can be designed independently. Based on the capacitive loading effect in the even mode operation, the solution sensing is implemented. For verification, a dual-band 1.8/2.4 GHz resonator is used as a probe to sense the volume of 0.9 wt% NaCl solution ranged from 0 μl to 20 μl. It is observed that the lower operating frequency is unaltered but 100 MHz frequency variation around the upper resonant frequency is recorded.