This article presents the theoretical study and experimental validation of the multipactor (MP) effect in bandpass

filters implemented in groove gap waveguide (GGW) technology. Such filters are based on inductive coupling irises and rectangular cavities, whose optimized dimensions (widths and lengths) are fixed between rows of metal pins. For validation and comparative purposes, experimental results for both the GGW and its counterpart realized in standard rectangular waveguide (RW) technology, are included. For the effective design of the considered GGWfilter, an equivalent counterpart in standard RWtechnology will be first studied, using very efficient tools for computing its electrical response and MP discharge breakdown level. Both filter prototypes, designed to operate at 17.5 GHz (for Ka-band satellite downlink applications), are made of aluminium, whose properties (in terms of secondary electron emission) have been measured and duly considered in their theoretical analysis (of multipactor breakdown thresholds) using available software tools. An outstanding matching between all predicted and experimental results is achieved.