Multi-band planar antenna array

Claim 1

An antenna comprising, a planar antenna (100) including a main array (110) comprised of a plurality of coplanar antenna sub-arrays (10), each of said antenna sub-arrays comprises a multilayer structure which includes: a radiating layer (30) including a plurality of at least three groups of radiating elements (11, 12, 13) which are respectively capable of operating with and radiating electromagnetic signals of different frequency bands; the radiating elements in each group are substantially identical to each other in size and configuration; the radiating elements in each group are substantially different in size from the radiating elements in the other groups; the radiating elements in different groups are operable for radiating electromagnetic signals of different frequency bands wherein the frequency bands differ by approximately 50% of the mid-frequency band and have a bandwidth of approximately 10%-20% of the mid-frequency; said different frequency bands comprise the X band, the C band and the Ku band; first and second conductors related to each of said groups of radiating elements and disposed at said radiating layer; said first conductor related to each group of radiating elements connected to a first position on each of said radiating elements in a group of radiating elements capable of operating at the same frequency band; said second conductor related to each group of radiating elements connected to a second position on each of said radiating elements in a group of radiating elements capable of operating at the same frequency band; source means (34) for supplying energy to said radiating elements via the respective first and second conductors related to a group of radiating elements to produce the electromagnetic signals radiated thereby; control means for controlling the selective connection of said source means to different positions on said radiating elements in order to achieve either left-hand-circular polarization or right-hand-circular polarization; a reflecting layer (32) of metal for directing the electromagnetic signals radiated by said radiating elements included at said radiating layer; a first electrically insulating layer (31) interposed between said radiating layer and said reflecting layer; a polarizing layer (22) disposed over said radiating layer and including a pattern (22A) of metal thereon for influencing the polarization of the electromagnetic signals radiated by said radiating elements of said radiating layer; a signal forming layer (26) of metal disposed over said polarizing layer; a second electrically insulating layer (29) interposed between said signal forming layer and said radiating layer; and a third electrically insulating layer (25) interposed between said polarizing layer and said signal forming layer, each said insulating layer is formed of a closed-cell polystrene material.