In order to achieve the stable confinement of ions in ion traps, a radio frequency (RF) source based on electronic tube oscillation circuit is constructed in this work. The device can simultaneously generate two RF electric fields with equal amplitudes and opposite phases, and its output frequencies are continuously adjustable ranging from 2.15 MHz to 4.05 MHz without active impedance matching. Over a continuous measurement period of 4.68 × 10⁴ s, the stabilities of frequency, phase difference, and dual-channel voltage peak-to-peak values of the RF source are evaluated after being installed on an ion trap, and the minimum Allan derivations of each parameter's stability are obtained to be 10^-5, 10^-4, and 10^-4 orders of magnitude, respectively. Furthermore, calcium ions are successfully confined in the ion trap equipped with the designed RF source, and by continuous adjusting the RF frequency and amplitude without turning off the RF source, the structural variations of the calcium ion Coulomb crystal are observed by CCD camera.