Most commonly used magnetron configuration Among practical magnetron types, which physical structure is most commonly used in microwave transmitters and radar sources?

Introduction / Context:
Magnetrons are high-power microwave oscillators widely used in radar and microwave ovens. Their geometry strongly influences mode structure, efficiency, cooling, and manufacturability. Recognizing the standard configuration helps in understanding performance and common implementation details in RF power sources.

Given Data / Assumptions:

• Typical pulsed and continuous-wave magnetron applications (e.g., radar, heating).
• Focus on physical geometry of the interaction space and resonator anode block.

Concept / Approach:
The overwhelming majority of practical magnetrons use a cylindrical configuration: a central thermionic cathode surrounded by a cylindrical anode block with resonant cavities. Radial crossed electric and magnetic fields force electrons into azimuthal motion, transferring energy to the RF fields in the cavities. The cylindrical shape is compact, mechanically robust, and supports the desired pi-mode operation with good efficiency.

Step-by-Step Solution:

Verification / Alternative check:
Commercial and military magnetron datasheets illustrate cylindrical cavity blocks (e.g., strapped magnetrons), confirming prevalence.

Why Other Options Are Wrong:

• Parallel/inclined/flat plate: not standard magnetron geometries for efficient microwave generation; plate structures are not used for conventional high-power magnetrons.

Common Pitfalls:
Confusing magnetron geometry with klystron or traveling-wave tube structures, which are linear rather than cylindrical cavity arrays.

Final Answer:
cylindrical