Different ion mobility (IM) separation techniques offer capabilities that are unique in one aspect. For example, collision cross sections (CCS) can be directly calculated from drift time measurements in a constant field IM platforms. Oscillatory field IM (such as traveling wave IM) has low voltage requirements but calculating CCS cannot directly obtained from drift time measurements and require calibration against compounds of known CCS measured in another constant field IM device. Traveling wave-based IM instruments can achieve extremely high resolution but accurate CCS require measurements in a different device. Therefore, it is beneficial to have one instrument that combine constant and oscillatory field IM. We disclose an array of embodiments for a device that seamlessly and efficiently perform constant field IM and oscillatory field IM.