Relative power handling at a given frequency: For comparable physical size, a hollow waveguide generally handles more RF power than a coaxial line. Is this statement correct?

Introduction:
High-power RF transport favors structures that minimize dielectric heating, avoid breakdown, and distribute fields over larger areas. This question compares waveguides and coaxial lines in terms of their typical power-handling capabilities at the same operating frequency and comparable size.

Given Data / Assumptions:

• Air-filled rectangular or circular waveguide versus dielectric-filled coaxial line.
• Similar external size and frequency.
• Clean, dry (or pressurized) waveguide environment.

Concept / Approach:

Waveguides usually contain only air (or dry gas) in the high-field region, which has very low loss tangent and good breakdown strength. Their larger cross-section spreads the electric field, reducing peak field intensity and conductor current density for a given power. Coaxial lines, however, typically employ solid dielectrics that limit breakdown and introduce dielectric loss, which constrains average and peak power. Therefore, waveguides generally handle more power at a given frequency and size.

Step-by-Step Solution:

Verification / Alternative check:

Manufacturer ratings routinely show WR-series waveguides carrying tens to hundreds of kilowatts pulsed; similarly sized coax is rated substantially lower due to dielectric constraints.

Why Other Options Are Wrong:

• False: ignores the dielectric and field-distribution advantages of waveguides.
• Conditional options cite irrelevant constraints like “below cutoff” (no propagation) or extreme frequency limits.

Common Pitfalls:

Assuming pressurization is optional in all cases; contaminants or humidity can reduce breakdown in waveguides, but intrinsic capability still favors waveguides over coax.

Final Answer:

True