Identify the Balanced Transmission Line Which of the following transmission lines is inherently a balanced line (equal and opposite conductors with respect to ground)?

Introduction / Context:
Balanced versus unbalanced transmission determines how currents return and how a line couples to nearby structures. Balanced lines carry equal and opposite currents on two conductors with minimal common-mode radiation.

Given Data / Assumptions:

• “Balanced” means symmetrical conductors with respect to ground.
• We compare common RF interconnect types.

Concept / Approach:

TV twin lead is the classic two-wire balanced line: both conductors are equivalent and neither is tied to ground. Coaxial line is unbalanced (outer conductor often at ground potential). Microstrip and single-ended stripline use a single signal conductor over/within a ground reference, also unbalanced.

Step-by-Step Solution:

Verification / Alternative check:

Baluns (balanced-to-unbalanced transformers) are used to interface twin-lead to coax, highlighting the difference.

Why Other Options Are Wrong:

Coax and microstrip/stripline are unbalanced by default; waveguide supports TE/TM modes and is not a two-conductor balanced line.

Common Pitfalls:

Assuming “differential stripline” equals “strip line” generically; the default single-ended stripline is unbalanced unless specifically routed differentially as a pair.

Final Answer:

TV twin lead