Coplanar Step C_STEP

Notes :

The difference between measurement and simulation is increasing with higher frequencies. That becomes obvious in the curve of |S₁₁|. The explanation for this deviation is, that the FD simulator calculates the equivalent circuit elements utilizing the static effective permittivity. For coplanar line configurations, the effective permittivity increases with the frequency. Two examples (utilizing a spectral domain analysis):
50W¹ CPW:

Z_{L_static}=48.4W, Z_L(50GHz)=49.13W, Z_L(60GHz)=49.13W
e_{eff_static}=6.66, e_eff(50GHz)=7.109, e_eff(60GHz)=7.202

40W⁵ CPW:

Z_{L_static}=39.4W, Z_L(50GHz)=40.43W, Z_L(60GHz)=39.88W
e_{eff_static}=6.66, e_eff(50GHz)=7.04, e_eff(60GHz)=7.106

Configuration: 50W1 lines at the ports, 40W5 CPW line (with d=240mm) in the middle; step parameter: SL=75mm; There is no step in the center line, but in the ground strips. total size: X=3700mm, Y=650mm

Configuration: 50W1 lines at the ports, 50W4 (with d=293.5mm) CPW line in the middle (len=900mm); step parameter: SL=50mm; total size: X=3350mm, Y=650mm

Configuration: 50W1 lines at the ports, 70W7 CPW line (with d=202mm) in the middle; step parameter: SL=75mm; total size: X=3700mm, Y=650mm

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