A dual-mode microwave resonator for double electron-electron spin resonance spectroscopy at W-band microwave frequencies

► We have developed a dual-mode microwave resonator operating at W-band frequencies. ► It supports two microwave modes with the same field polarization at the sample. ► The frequency separation between the modes can be tuned in a broad range. ► The resonator has been used for DEER with a large separation of applied frequencies.