We focused on a unique pattern of resonator, named double spiral resonator in WPT via resonance coupling, which is suitable for printing on ultra-thin and cheap substrates such as paper or film with ink-jet printing technology, concluding design trade-offs for the fabrication of double spiral resonator by investigating different structural parameters' effect on peak transmission efficiency. By conducting contrast experiments with other two patters of resonators, the fact that double spiral resonator ensured higher peak transmission efficiency in longer distance has been proved. Five structural parameters of double spiral resonator have been investigated on the effect of peak transmission efficiency. As well, equivalent circuit analysis on peak transmission efficiency has also been derived to inspect the theoretical explanation of the phenomenal parameters' effect on transmission efficiency.