The single-layer reduction (SLR) formulation is presented to compute the propagation characteristics, that is, the slowing factor (normalized phase constant) and the attenuation constant of the even and odd modes of the suspended MIS coupled slow-wave microstrip lines. The proposed structure is suitable for the design of a compact high-directivity coupler. For the standard coupled MIS microstrip line the SLR computes the slowing factor with deviation about 1% and the attenuation constant with 0.005 dB/mm difference against results of the spectral domain analysis (SDA). The SLR is as accurate as the SDA; however, computationally it is much faster than the SDA.
- Attenuation constant
- Multilayer coupled microstrip line
- Slowing factor