Coupled line model is avaliable in Cadence Spectre.
Here I confirmed Coupled line model in Cadence Spectre by simple balun.
Fundamental balun operation itself is no problem.
However dependecy of substrate thickness is fairly different from Keysight ADS result.
I think Keysight ADS result is reasonable.
Here I use "MACLIN3 (Microstrip 3-Conductor Asymmetric Coupled Lines)" in Keysight ADS.
On the other hand, I use "rfTlineLib/nclin" in Cadence Spectre.
Why does "rfTlineLib/nclin" in Cadence Spectre give fairly different results ?
Code:// Generated for: spectre
// Generated on: Aug 30 15:26:54 2018
// Design library name: My_RFDE_Test
// Design cell name: Design_of_a_Planar_Microstrip_Balun_at_S_band
// Design view name: schematic
simulator lang=spectre
global 0
parameters h=0.004 X=0.3m
// Library name: My_RFDE_Test
// Cell name: Design_of_a_Planar_Microstrip_Balun_at_S_band
// View name: schematic
stackup0 stackup names=["ground" "core" "signal" ] type=["Ref" "Diel" \ "Cond" ] thickness=[35u h 35u ] material=[stackup0_Copper \
stackup0_FR4 stackup0_Copper]
stackup0_FR4 dielectric type="const" nd=2 data=[4.3 0.018 ]
stackup0_Copper conductor type="smooth" nd=1 data=[5.813e7 ]
nclin2 (net02 0 net7 net07 net02 0 0 0) mtline stackup=stackup0 \
layer=["signal" ] len=(12.8m) linewidth=[(750u) (850u) (750u) ] \
linespace=[(X) (X) ]
nclin0 (0 net5 net8 net7 0 net5 0 0) mtline stackup=stackup0 \
layer=["signal" ] len=(12.8m) linewidth=[(750u) (850u) (750u) ] \
linespace=[(X) (X) ]
PORT1 (net8 0) port r=50 num=1 type=dc
PORT3 (net02 0) port r=50 num=3 type=dc
PORT2 (net5 0) port r=50 num=2 type=dc
simulatorOptions options psfversion="1.1.0" reltol=1e-3 vabstol=1e-6 \
iabstol=1e-12 temp=25.0 tnom=25.0 scalem=1.0 scale=1.0 gmin=1e-12 \
rforce=1 maxnotes=5 maxwarns=5 digits=5 cols=80 pivrel=1e-3 \
sensfile="../psf/sens.output" checklimitdest=psf
sp sp start=1.9G stop=3.9G step=0.01G annotate=status