Study of the characteristic impedance of gap waveguide microstrip line realized with square metal pins

This paper addresses how to define the numerical ports in the gap waveguide microstrip line, and also a study of its characteristic impedance when the parallel-plate stopband is realized by using metal pins. The results presented here are produced using commercially available EM simulators. The paper also includes a study of how to minimize the effect of the transverse locations of the pin structure under the microstrip line, relative to the location of the strip.