Primary radiator having reduced side lobe
AssigneeAlps Electric Co., Ltd.
InventorDou Yuanzhu
Life of this patent
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Abstract
The primary radiator comprises a circular waveguide having a cone-shaped horn portion at one end and an enclosing surface at the other end, and a first and second probes inserted into the waveguide through a wall thereof. A plurality of cutout portions are formed at an open end of the horn portion. Two or more pairs of cutout portions are disposed symmetrically with respect to an axis of the waveguide and a depth of each cutout portion is adjusted to be about one quarter of the wavelength of the radio wave λ0 transmitted through the air. With such a configuration, the phase reversal of surface currents flowing through the cutout portions and an adjacent projecting portion (a portion without cutout portions) take place, and a side lobe of a radiation pattern can be reduced considerably.
Claims20
A primary radiator comprising:
- a waveguide having a horn portion that includes a funnel-shaped wall surface at one end for introducing radio waves;
- and
- a probe for receiving at least one component of polarization of radio waves entering the waveguide,
- wherein at least a pair of cutout portions having a depth of about one quarter of the wavelength of the radio waves are provided at an opening end of the horn portion along the funnel-shaped wall surface;
- and
- wherein the at least a pair of cutout portions is configured to reduce side lobes generated by surface current flowing at the funnel-shaped wall surface of the horn.
A primary radiator comprising:
- a waveguide having a horn portion at one end for introducing radio waves;
- and
- a first probe provided in said waveguide for receiving at least one polarization component of radio waves entering the waveguide,
- wherein at least two cutout portions are formed in the wall of said horn portion to extend from the open end edge of said horn portion over a depth which is about one quarter of the wavelength of the radio waves, said two cutout portions being sized so as to reduce side lobes caused by surface currents flowing along the surface of said horn portion through said probe.
A primary radiator comprising:
- a waveguide having a funnel-shaped horn portion at one end for introducing radio waves, the horn portion defined by an outer wall extending toward an opening end that terminates in a rim;
- wherein the rim of the horn portion includes a plurality of projections and a plurality of depressions formed alternately along the rim at the opening end of the funnel-shaped horn portion such that the plurality of projections and depressions are formed by at least one pair of cutout portions in the outer wall and the at least one pair of cutout portions are disposed symmetrically with respect to an axis of the waveguide;
- wherein the at least a pair of cutout portions is configured to reduce side lobes generated by surface current flowing at the funnel-shaped wall surface of the horn;
- and
- at least one probe for receiving at least one component of polarization of radio waves entering the waveguide.
A primary radiator comprising:
- a waveguide having a horn portion at one end for introducing radio waves, the horn portion of the waveguide having a wall surface;
- and
- a first probe provided in said waveguide for receiving at least one polarization component of radio waves entering the waveguide,
- wherein at least two cutout portions are formed in the wall surface of said horn portion to extend from an open end edge of said horn portion over a depth which is about one quarter of the wavelength of the radio waves, said two cutout portions being configured to reduce a side lobe caused by surface current flowing at the surface of said horn portion through said probe.
Dependencies are inferred from the claim text.