Aerial inventory antenna
The present invention relates to a dual polarization radio frequency identification antennae for automatically reading and locating inventory when moved and rotated by an inventory-scanning UAV or robot having three dimensions of position mobility.
1. A dual polarization antenna for scanning RFID transponders comprising:
a hollow central core having a polygon shape with about a 1.5 inch cross section and a length of about 2 inches wherein the outer skin is electrically conductive;
an RFID interrogator wherein the interrogator is located within the hollow central core with a first and a second antenna feed point extending through the surface of the skin;
a toroidal reflector loop having a diameter of about 4.4 inches;
a first helical exciter element having a diameter of about 4.0 inches with about 1.2 inches between the turns and located above the reflector loop wherein the proximal end of the exciter curls inward to connect with the first antenna feed point;
a second helical exciter element having a diameter of about 4.0 inches with about 1.2 inches between the turns and located above the first helical exciter element wherein the proximal end of the exciter curls inward to connect with the second one of the antenna feed point;
a toroidal director loop having a diameter of about 3.7 inches wherein the director loop is located above the second helical exciter element.
2. The antenna of claim 1 further comprising a second toroidal director located above the first toroidal director.
3. The antenna of claim 1 , wherein the reflector, exciters, and director elements are made of 16 AWG brass wire.
4. The antenna of claim 1 , wherein the reflector, exciters, and director elements are made of half hard brass wire.
5. The antenna of claim 1 , wherein the proximal ends of the exciters are fed by an impedance-matching network.
6. The antenna of claim 1 , wherein the exciters are mechanically supported at low voltage points.
7. The antenna of claim 1 , wherein the outer skin is thermally conductive.