Stepped Impedance Lowpass Filter in ADS

[monolothics]

Hi..

i'm currently designing LPF using stepped impedance that operate at 9.4 GHz and also i want my LPF have constant 90° phase shift at 9.4 GHz
so after i have the L-C value, i transform it to microstrip with

dielectric constant (εr) = 2.33
dielectric thickness (h) = 0.787 mm

and
Zlow = 10 Ω
Zhi = 110 Ω

so when i simulate it using schematic in ADS i get very good output,
but when i simulate it in ADS layout using microwave simulation i can't get the exact result like the one i simulate using schematic

anyone has an idea??

here's a picture

 

[BigBoss]

Ports are very close therefore there may be a calibration error because of coupling.Instead of that, connect the ports to extended MS Lines with 50 Ohm to push out the ports each other.

 

[monolothics]

Hi Big Boss
thx for the reply

but how to decide the length of the 50 ohm ms line??? i tried to use linecalc in ads and tried an arbitrary length of microstrip line then i simulate it but the result is still far from the scematic result.