The present disclosure generally relates to a device having a variable frequency filter that rejects harmonics generated by a variable reactance device. The variable frequency filter may be coupled to the antenna and the variable reactance device. The filter includes a variable capacitor and an inductor coupled together as a resonant circuit. The filter may be used in cellular technology to prevent harmonic frequencies that are created by another variable reactance device from reaching the antenna of the cellular device. Furthermore, the filter can reflect any receiving frequencies from the antenna and prevent the receiving frequencies from passing through.