In a circular resonant cavity with flat...

🔍 Key Concepts

• Electromagnetic cavity modes in a cylindrical (circular) waveguide with flat end plates • Relationship of E-field lines to conducting boundaries (they must be perpendicular to perfect conductors at the surface) • Relationship of H-field lines to conducting boundaries (they tend to run parallel to the surface of a perfect conductor)

💭 Think About

• Think about how electric field lines must meet a perfectly conducting metal surface at the end walls versus the side walls. Which orientation is allowed at a conductor? • For a resonant mode in a circular cavity, where do magnetic field lines typically circulate with respect to the axis and the end plates? • Which options, if any, would violate the boundary condition that the tangential electric field at a perfect conductor must be zero at the surface?

✅ Before You Answer

• Check which choice correctly makes E-field lines perpendicular to conducting surfaces where the tangential E-field must be zero. • Verify which description of H-field lines is consistent with them forming closed loops parallel to conductor surfaces and encircling displacement currents or charges. • Eliminate any options that would require a non‑zero tangential E-field at a perfectly conducting flat end or side wall.

In a circular resonant cavity with flat ends, the E-field and the H-field form with specific relationships. The:

E-lines are parallel to the top and bottom walls.

E-lines are perpendicular to the end walls.

H-lines are perpendicular to the side walls.

H-lines are circular to the end walls.

🔍 Key Concepts

💭 Think About

✅ Before You Answer