| 摘要 |
A feed that provides circularly polarized microwave energy such as for energizing a microwave oven cavity. The feed includes a transformer to match a linearly polarized rectangular waveguide to a polarization waveguide section which may be circular or square in cross section. The polarization waveguide section contains an asymmetrical element that provides symmetry about a plane only. The asymmetrical element therefore introduces a difference in microwave electrical phase for polarizations which are respectively parallel to and perpendicular to the symmetry plane. A second waveguide section having a bend is also used in the feed assembly. The second waveguide section, which may for example be a bent section of circular waveguide, also presents an electromagnetic symmetry about a plane only. As a result, the two waveguide sections operating together provide circularly polarized energy at constant magnitude but continually rotating phase.
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