Week 06
Microstrip Lines
I revisit transmission lines through Wilkinson and branch-line networks using my assignments, Cadence circuits, and S-parameter figures.
What I connect in this unit
A microstrip's fields occupy both substrate and air, so effective permittivity describes its propagation speed. The line-width to substrate-height ratio strongly sets characteristic impedance, while dispersion makes a single εeff approximation frequency dependent.
Concept map
- Effective permittivity
- Line width
- Substrate height
- Dispersion
Technical anchor
Estimate εeff and Z0 from W/h and εr, then calculate λg=c/(f sqrt(εeff)). When solving for W at a target Z0, also check whether the width is manufacturable.
How I review it
Vary substrate height and εr within plausible tolerances to tabulate Z0 and electrical-length sensitivity, and include abrupt width changes and reference-plane placement in the layout review.
Connection to the full course
Unit 6 of 12. Unit numbers arrange the saved assignments and circuits by concept flow rather than attendance weeks.