Ridge waveguide vs. standard rectangular waveguide – Usable bandwidth comparison How does the usable bandwidth of a properly designed ridge waveguide compare with that of a conventional rectangular waveguide (same outer cross-section)?

Introduction:
Ridge waveguides introduce one or two metallic ridges inside a rectangular waveguide to modify field distribution and dispersion. The goal is to lower cutoff, flatten impedance variation, and extend single-mode or low-loss bandwidth for practical components such as couplers, filters, and transitions.

Given Data / Assumptions:

• Comparison at the same external size envelope.
• Properly designed ridge geometry (gap and ridge height selected for the band).
• Focus on usable (single-mode/low-VSWR) bandwidth.

Concept / Approach:

By concentrating the electric field in the ridge gap, the effective capacitance increases and the TE10 cutoff frequency is reduced. This widens the frequency region between the new (lower) cutoff and higher-order mode onsets, enabling a broader useful passband with better match and power handling for many applications.

Step-by-Step Solution:

Verification / Alternative check:

Design curves and EM simulations of ridge guides show extended bandwidths used in broadband transitions and couplers.

Why Other Options Are Wrong:

Options A, C, D contradict the purpose of the ridge. Option E is incorrect; ridge guides still support TE modes.

Common Pitfalls:

Assuming ridges always increase loss; properly designed ridges maintain acceptable attenuation over a wider band.

Final Answer:

is higher than that of rectangular waveguide.