Conference Publication Details
Mandatory Fields
Ibrahim S.;Szczepkowski G.;Farrell R.
IET Conference Publications
The effect of impedance mismatch on phase linearity of GCPW loaded transmission lines and shunt stubs
Optional Fields
Coplanar waveguides Impedance mismatch Linear phase Phase shifters Shunt stubs Switched delay lines
This paper presents a study on the effect of impedance mismatch on phase linearity (group delay variations) in grounded coplanar waveguide (GCPW) structures. Two 400 ps GCPW delay lines were designed using a short circuited stub and a transmission line. The structures were simulated over a wide frequency range (0.1 GHz-5 GHz) using both ADS circuit model and CST electromagnetic simulation tool. Based on mathematical analysis and simulation results, impedance mismatch appears to have a large effect on group delay variations in stubs when compared to transmission lines. The simulated time delay of the short circuited stub shows a maximum delay deviation of ±0.75% and ±7.4% for 1.6% and 5.8% impedance mismatch values, respectively. On the other hand, the transmission delay line simulation results show only ±0.1% and ±1.5% for the same impedance mismatch. For the electromagnetic simulation, the presented results indicate even larger variation of time delay for GCPW short stub as it reaches ±3.75% and ±7.5% at 2 GHz and 4.5 GHz for 1.6% impedance mismatch, respectively.
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