This paper presents an independently adjustable dual-band bandpass filter. The filter is mainly composed of a pair of varactor-loaded parallel coupling short circuits

a pair of

λ

/2 varactor-loaded open resonators

and a common input/output component. The varactor diode and the parallel coupling short circuits are connected in parallel to form a resonator which produces the first passband. The

λ

/2 varactor-loaded open resonators are used to load the varactors and produce the second passband. By adjusting the bias voltage on the varactors to change the capacitance value of the varactors

the resonant frequency of the resonators can be shifted and thus t

he operating frequency of the filter can be adjusted. Both the simulation and testing results show that

the center frequencies of the first and second passbands range from 0.2 to 0.4GHz and from 1.2 to 1.42GHz

respectively

and their adjustment percentages are 66.5% and 15.4%

respectively. The simulation results are well consistent with the testing results

proving that our filter design method is effective. The designed filter can be applied to the cheat prevention and control system.