Planar antenna directional in azimuth and/or elevation
First Claim
1. A steerable antenna comprising an electrically conductive layer on a dielectric substrate, the conductive layer defining a plurality, k, of coaxial ring-slot radiating elements formed therethrough, and controllable signal feed means coupled to each said ring-slot element, and wherein said feed means selectively feed j of said k ring-slot radiating elements where j is in the range of 1 to k to excite a separate resonant mode on each of said ring-slot radiating elements, the mode excited being dependant upon the geometry of the respective said ring-slot radiating element, and generally lying in the plane of the conductive layer or the dielectric substrate, and wherein radiation due to said resonant modes combine by superposition in the far-field to produce a radiation pattern directional in azimuth and elevation, and said feed means is controllable in amplitude and phase to adjust the relative amplitude and relative phase of the excited modes to steer said radiation pattern in azimuth and elevation.
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Abstract
A directional planar antenna is disclosed. The antenna has an array of coaxial ring-slot radiating elements formed through a conductive layer on a dielectric substrate. A number of probes, coupled to the ring-slot elements, selectively excite a separate resonant mode on each ring-slot element. The resonant mode supported by a ring-slot element depends upon the geometry of that ring-slot element. The resonant modes combine in the far field to form a radiation pattern directional in azimuth and elevation. By adjustment of the relative phase difference or relative amplitude between the excited modes, the radiation pattern can be steered.
137 Citations
16 Claims
- 1. A steerable antenna comprising an electrically conductive layer on a dielectric substrate, the conductive layer defining a plurality, k, of coaxial ring-slot radiating elements formed therethrough, and controllable signal feed means coupled to each said ring-slot element, and wherein said feed means selectively feed j of said k ring-slot radiating elements where j is in the range of 1 to k to excite a separate resonant mode on each of said ring-slot radiating elements, the mode excited being dependant upon the geometry of the respective said ring-slot radiating element, and generally lying in the plane of the conductive layer or the dielectric substrate, and wherein radiation due to said resonant modes combine by superposition in the far-field to produce a radiation pattern directional in azimuth and elevation, and said feed means is controllable in amplitude and phase to adjust the relative amplitude and relative phase of the excited modes to steer said radiation pattern in azimuth and elevation.
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15. A method of electronically steering a far-field radiation pattern of a planar antenna in elevation and azimuth, said antenna comprising an electrically conductive layer on a dielectric substrate, said conductive layer defining a plurality, k, of ring-slot radiating elements formed therethrough, and having controllable signal feed means coupled to each said ring-slot radiating element, said method comprising the steps of:
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selectively feeding j of said k radiating elements, where j is in the range of 1 to k, to excite a separate resonant mode on each of said j radiating elements, the mode excited being dependent upon the geometry of the respective said ring-slot radiating elements and radiation due to said resonant modes combining by superposition in the far-field to produce a radiation pattern directional in azimuth and elevation; and adjusting the relative amplitude and relative phase of the excited modes to steer said radiation pattern in azimuth and elevation. - View Dependent Claims (16)
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Specification