Spherical antennas having isotropic radiation patterns
First Claim
1. An antenna comprising:
- a substantially spherical body having a center and an outer conductive surface;
two spaced conductive members located in said body providing a resonant cavity therebetween and including an annular slot communicating with said outer surface, said spaced conductive members being displaced from the center of said body for locating said annular slot in a polar region on said body; and
first and second probe means having respective conductors connected to one of saaid spaced conductive members for coupling between wave energy in said resonant cavity and signal energy, said probes being angularly displaced from each other by 90°
about said center for coupling energy to said one spaced conductive member in a quadrature phase relation.
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Abstract
Spherical antenna arrangements are disclosed utilizing annular slots in polar regions which are associated with resonant cavities having a TE01 mode or a TE11 mode of field distribution. This field distribution within the cavity produces a cosine field distribution around the annular slot which serves via proper cavity excitation to produce nearly hemispherical isotropic radiation characteristics. The resonant cavities may take on the form of a parallel-plate structure or a coaxial cylindrical structure. Circular polarization and hemispherical coverage with uniform gain is characteristic of the antenna when the cavities contain probes placed ninety degrees apart in azimuth at the same radius from center and coupled to the quadrature phase related ports of a signal coupler.
17 Citations
14 Claims
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1. An antenna comprising:
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a substantially spherical body having a center and an outer conductive surface; two spaced conductive members located in said body providing a resonant cavity therebetween and including an annular slot communicating with said outer surface, said spaced conductive members being displaced from the center of said body for locating said annular slot in a polar region on said body; and first and second probe means having respective conductors connected to one of saaid spaced conductive members for coupling between wave energy in said resonant cavity and signal energy, said probes being angularly displaced from each other by 90°
about said center for coupling energy to said one spaced conductive member in a quadrature phase relation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification