Propagation Characteristics of Groove Gap Waveguide Below and Above Cutoff

Recently, gap waveguides have been shown as a potential alternative to convenational waveguides in the millimeter-wave band. Until now, groove gap waveguide (GGW) has been studied through direct correspondence with rectangular waveguide with the same physical dimensions. However, there have been observed differences in the above cutoff propagation characteristics between these two waveguide types. Furthermore, the behavior of GGW below cutoff remains unknown. This work presents a discussion of both below and above cutoff propagation characteristics of GGW, and introduces a simple model that explains the observed GGW behavior and establishes well its propagation characteristics. Two thru-reflect-line calibration kits have been manufactured, and the measurements have good agreement with the proposed analysis model results.