A novel method for modeling bends in coplanar waveguides (CPWs) is described.
The CPW can be viewed as a pair of parallel coupled quasi-slot lines.
Bends in the CPW are modeled as a non-uniform coupled line system in terms of
their even- and odd- mode characteristics. This modeling approach is general and
can be applied for bends with different angles and other similar discontinuities in the
CPW. The salient feature of the model is the simplified illustration of frequency dependent
effects in the bend. Right-angle, 45 degree, and mitered right-angle
bends in the CPW are analyzed, and models are developed for each bend structure.
The procedure for extracting the modal scattering matrix from the model is presented.
To demonstrate the accuracy of the model, modal transmission coefficients
obtained from the model are compared with full-wave electromagnetic simulations.
Good agreement between the model and full-wave simulation results over a wide
frequency range is demonstrated.
The transfer of energy between even and odd modes in the bend is investigated
and the effect of the physical properties of the CPW on mode conversion
is analyzed in detail. Mode conversion at discontinuities like the bend in CPWs
cause non-ideal behavior in the two-port (even-mode) measurements of such circuits.
Theoretical prediction of the measured response is discussed along with the
predicted response for transmission coefficient from model and full-wave simulations.
Comparison between the measurements of a right-angle bend and the corresponding
model results shows good agreement. Implementation of the model in SPICE is also
discussed. / Graduation date: 2004
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/29271 |
| Date | 08 December 2003 |
| Creators | Senguttuvan, Rajarajan |
| Contributors | Weisshaar, Andreas |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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