Abstract: Embodiments of a tunable radio frequency (RF) diplexer and methods of operating the same are disclosed. In one embodiment, the RF diplexer includes a first hybrid coupler, a second hybrid coupler, an RF filter circuit, and a phase inversion component. Both the RF filter circuit and the phase inversion component are connected between the first hybrid coupler and the second hybrid coupler. The phase inversion component is configured to provide approximately a differential phase. The RF filter circuit is configured to provide a passband and a notch. The RF filter circuit is tunable to provide the notch on both a high-frequency side of the passband and a low frequency side of the passband. Accordingly, the tunable RF diplexer provides lower insertion losses and higher isolation regardless of whether the one of the diplexed frequency bands is set at higher frequencies or lower frequencies than the other diplexed frequency band.