Folded cross grid dipole antenna element
AssigneeAPTI, Inc.
InventorPaul G. Elliot
Life of this patent
Estimating the term…
Abstract
A wide bandwidth, wide scan, antenna array element provides an active element impedance close to 350 ohms over a bandwidth approaching one octave in a periodic equilateral triangular array lattice. The two balanced feed inputs to each element may be phased to produce any desired polarization. The interelement spacing is the maximum possible for grating lobe free operation. This antenna element combines features of a crossed grid dipole with a folded dipole. The antenna structure consists of conductors lying in two planes which are parallel to a ground plane. These are joined by a limited number of perpendicular conductors. The VSWR remains below 2:1 in a 300 or 350 ohm system for scan in any direction out to 30 degrees off of broadside over a bandwidth approaching one octave.
Claims28
An antenna element comprising:
- a ground plane
- a first crossed grid dipole, said first crossed grid dipole being arranged in an X-Y plane corresponding to a first tier, the first tier being vertically separated from a second tier and said ground plane, said second tier being located between said ground plane and said first tier, the first crossed grid dipole having an interconnected plurality of arms;
- a second crossed grid dipole, said second dipole arranged in an X-Y plane corresponding to said second tier, said second crossed grid dipole having a plurality of non-interconnected arms, each of said non-interconnected arms having a feed input;
- and
- said first crossed grid dipole being connected to said second crossed grid dipole by conductors.
An antenna element comprising:
- a ground plane
- first and second crossed grid dipoles located on first and second tiers, respectively, of said element, said second tier being interposed between said ground plane and said first tier at a first distance from said first tier, and a second distance from said ground plane;
- said first crossed grid dipole having a plurality of arms formed by conductors, each of said arms being connected at an interconnection point located at an approximate central vertical axis parallel to the Z axis of said element;
- said second crossed grid dipole having a plurality of non-interconnected arms formed by conductors, said conductors forming periphery corners at distances from said central vertical axis, said periphery corners being substantially vertically aligned and electrically connected to periphery corners formed by said conductors of said first crossed dipole, said conductors of said second crossed dipole arms further forming a single feed point for each arm, said single feed points surrounding said central vertical axis.
An array of antenna elements, each element of the array comprising:
- a ground plane;
- a first tier about 0.33 wavelengths above the ground plane and having a crossed grid dipole joined at a central point;
- and
- a second tier located between the ground plane and the first tier at about 0.23 wavelength from the ground plane and having a crossed grid dipole vertically aligned with the crossed grid dipole of the first tier, the crossed grid dipole of the second tier being electrically connected at exterior perimeter corners to the crossed grid dipoles of the first tier, interior corners of the grids of the second tier being non-interconnected and connectable to antenna feeds.
A method of radiating electromagnetic energy in an arbitrary direction over a predetermined wide angular region and over a wide frequency range, the method comprising the steps of:
- feeding an antenna element having
- a ground plane
- a first crossed grid dipole, said first crossed grid dipole being arranged in an X-Y plane corresponding to a first tier, the first tier being vertically separated from a second tier and said ground plane, said second tier being located between said ground plane and said first tier, the first crossed grid dipole having an interconnected plurality of arms;
- a second crossed grid dipole, said second dipole arranged in an X-Y plane corresponding to said second tier, said second crossed grid dipole having a plurality of non-interconnected arms, each of said non-interconnected arms having a feed input, said first crossed grid dipole being connected to said second crossed grid dipole by conductors;
- and
- connecting said element to a transmitter.
A method of receiving electromagnetic energy from an arbitrary direction over a predetermined wide angular region and over a wide frequency range, the method comprising the steps of:
- feeding an antenna element having
- a ground plane
- a first crossed grid dipole, said first crossed grid dipole being arranged in an X-Y plane corresponding to a first tier, the first tier being vertically separated from a second tier and said ground plane, said second tier being located between said ground plane and said first tier, the first crossed grid dipole having an interconnected plurality of arms;
- a second crossed grid dipole, said second dipole arranged in an X-Y plane corresponding to said second tier, said second crossed grid dipole having a plurality of non-interconnected arms, each of said non-interconnected arms having a feed input, said first crossed grid dipole being connected to said second crossed grid dipole by conductors;
- and
- connecting said element to a receiver.
Dependencies are inferred from the claim text.