Decoupled dipole configuration for enabling enhanced packing density for multiband antennas
Disclosed is a decoupling dipole structure that renders a midband dipole effectively transparent to a nearby lowband dipole. This not only improves the beam quality in the lowband without sacrificing beam quality in the midband, it also enables different lowband dipoles to be employed to customize the lowband performance of the multiband antenna without requiring a redesign of the midband dipoles or of the array face.
1. A dipole for a multiband antenna, comprising:
a balun stem; and
a radiator plate mechanically coupled to the balun stem, the radiator plate having a first side and a second side opposite the first side, four capacitive coupling elements disposed on the first side, and four folded dipole elements disposed on the second side, wherein each of the four capacitive coupling elements is capacitively and inductively coupled to a corresponding folded dipole element.
2. The dipole of claim 1 , wherein each capacitive coupling element has an inductive trace that electrically couples to a radiator inductive trace through a via formed in the radiator plate, the radiator inductive trace coupled to a corresponding folded dipole element disposed opposite the capacitive coupling element.
3. The dipole of claim 1 , wherein the four capacitive coupling elements comprise a first pair of capacitive coupling elements corresponding to a first polarization, and a second pair of capacitive coupling elements corresponding to a second polarization, and wherein the four folded dipole elements comprise a first pair of folded dipole elements corresponding to the first polarization and a second pair of folded dipole elements corresponding to the second polarization, the second polarization being orthogonal to the first polarization.
4. The dipole of claim 3 , wherein each of the first pair of folded dipole elements are electrically coupled to adjacent folded dipole elements of the second pair of folded dipole elements by a conductive trace.
5. The dipole of claim 1 , wherein the radiator plate comprises a PCB (Printed Circuit Board).
6. The dipole of claim 1 , wherein the four capacitive coupling elements and the four folded dipole elements each comprise Copper.
7. The dipole of claim 6 , wherein the four capacitive coupling elements and the four folded dipole elements each have a thickness of 1.4 mil.
8. The dipole of claim 1 , wherein the balun stem comprises two balun stem plates that are mechanically coupled in a cross pattern.
9. The dipole of claim 8 , wherein each of the four capacitive coupling elements is conductively coupled to a corresponding balun circuit trace diposed on a corresponding balun stem plate.
10. The dipole of claim 9 , wherein the first side comprises an upper surface and the second side comprises a lower surface.