Microstrip vs. Stripline: Identify a Key Disadvantage of Microstrip Interconnects Compared to embedded stripline, which drawback most commonly affects microstrip implementations on printed circuit boards?

Introduction / Context:
RF designers frequently choose between microstrip (a surface conductor over a dielectric with a ground plane below) and stripline (a conductor sandwiched between two ground planes). Understanding their electromagnetic behavior is essential for low-loss, low-noise layouts.

Given Data / Assumptions:

• Standard PCB materials and thicknesses.
• Comparable characteristic impedance targets.
• No special shielding enclosures.

Concept / Approach:

Microstrip is an open structure: its fields are partly in air and partly in dielectric. This makes it more susceptible to radiation and coupling to nearby structures. Stripline, being fully enclosed by ground planes, confines fields better, reducing radiation and crosstalk and often offering more consistent impedance and velocity.

Step-by-Step Solution:

Verification / Alternative check:

EM simulation and near-field scanning measurements typically show higher radiation from microstrip bends, stubs, and transitions than equivalent stripline designs.

Why Other Options Are Wrong:

Microstrip is perfectly suited to PCB fabrication (so A is wrong), is not bulkier (C), and is generally simpler/cheaper (D). Vacuum operation (E) is irrelevant.

Common Pitfalls:

Assuming microstrip always has higher loss; actual loss depends on dielectric, copper finish, and geometry.

Final Answer:

are more likely to radiate