Turnstile Junction
Understanding Turnstile Junction
The turnstile junction exploits the symmetry of the junction to couple between rectangular and circular waveguide modes. When used with a short circuit at one end, it can function as an orthomode transducer (OMT) separating two orthogonal polarizations.
| Antenna Type | Gain (dBi) | Beamwidth | Bandwidth |
|---|---|---|---|
| Dipole | 2.1 | 360° (H) | Moderate (~10%) |
| Patch | 5-8 | 60-90° | Narrow (2-5%) |
| Horn | 10-25 | 10-60° | Wide (>50%) |
| Parabolic | 25-45 | 1-10° | Wide |
Applications include dual-polarization antenna feeds, power combiners for high-power transmitters, and polarization diplexers. The junction's performance depends on precise machining of the central cavity and matching elements.
Frequently Asked Questions
What is a turnstile junction used for?
Primarily for orthomode transduction in antenna feeds, where it separates two orthogonal polarizations from a circular waveguide into two rectangular waveguide ports.
How does it differ from a magic tee?
A magic tee is a four-port junction in a single waveguide plane, while a turnstile junction connects waveguides arranged around a circular cross-section for polarization operations.