Definition Check: Transmission-Line Discontinuity A transmission-line discontinuity is defined as any interruption in the uniformity (geometry or material parameters) of the line. Is this statement correct?

Introduction / Context:
Accurate matching and modeling at RF/microwave frequencies requires recognizing what counts as a discontinuity. Discontinuities cause reflections and local field distortions, affecting return loss and bandwidth.

Given Data / Assumptions:

• A “uniform” line has constant R, L, G, C per unit length or constant cross-section and material fill.
• Any geometric, dielectric, or conductive change breaks uniformity.
• We are considering general transmission structures: coax, microstrip, stripline, and waveguide.

Concept / Approach:

A discontinuity is any localized change in impedance or propagation constant. Examples include steps in width/height, connectors, bends, junctions, posts, irises, tapers, or dielectric inserts. These can be modeled by equivalent reactive/ resistive networks that create reflections (nonzero Γ) even if losses are low.

Step-by-Step Solution:

Verification / Alternative check:

Field solvers and Smith chart experiments verify that even small geometry changes introduce measurable S11, demonstrating discontinuity behavior.

Why Other Options Are Wrong:

Limitations to coax (C) or “resistive only” (D) are unfounded; discontinuities can be purely reactive. Threshold VSWR (E) is arbitrary; any nonzero reflection qualifies.

Common Pitfalls:

Ignoring very small features as “negligible”; at high frequency, even small steps can matter.

Final Answer:

True