A new property of tunable lumped-distributed circuits, namely, the intersection effect of resonant regions of two resonators with variable capacitors, is observed. As is known, the resonant regions of widely used resonators with varactors are separated by frequency intervals from each other. The construction of the proposed resonators is based on the resonance equations. One resonator is a loop hairpin stepped-impedance resonator with one capacitor. In this resonator, a controlled regime of dual-mode oscillations is realized, when the even and odd modes of the oscillations can change places. For this a one variable capacitor is used only. Another resonator is a symmetrical stepped-impedance resonator with two capacitors at the ends. Its resonance regions for several oscillations with frequencies ${f} _{0}$ , ${f} _{1}$ , ${f} _{2}$ intersect each other. This effect allows tuning in a very wide frequency range with simultaneous use of these oscillations. The results of the measurements and simulation for the reconfigurable microstrip dual-mode filter with one capacitor are presented.