Antenna element used for multi-band antenna dual polarization

1. An antenna element used for multi-band antenna dual polarization, comprising: four radiating elements, a balun element configured to feed power to the radiating elements, and a fastening plate configured to fasten the balun element, wherein

the balun element comprises two dielectric plates, the two dielectric plates being embedded into each other in a crossing manner, two signal transmission units, one feeding unit, and two filtering units printed on each dielectric plate ( 203 ), the filtering units being used for decoupling; and, wherein

each of the filtering units comprises one or more filtering modules, wherein the one or more filtering modules are connected in parallel or in series, wherein

a given one of the one or more filtering modules comprises a first metal piece and a second metal piece, wherein

the first metal piece is printed on the second surface of the dielectric plate, and the first metal piece at least partially overlaps the signal transmission unit in space; and

the second metal piece is disposed at a top end and/or a bottom end of the first metal piece, the second metal piece and the first metal piece are welded to each other, and the second metal piece does not overlap the signal transmission unit in space; and

the two signal transmission units are disposed on a first surface of each dielectric plate, wherein top ends of the four signal transmission units are electrically connected to bottom ends of the four radiating elements respectively, the feeding unit being disposed on a second surface that is of each dielectric plate and that is opposite to the first surface, and a bottom end of the feeding unit and bottom ends of the signal transmission units are electrically connected to the fastening plate separately.

2. The antenna element according to claim 1 , wherein the two dielectric plates are embedded into each other in a cross-shaped manner, and the two dielectric plates are disposed in a vertically staggered manner; and

a target gap is provided on a side face, facing the balun element, of the fastening plate, wherein the target gap is in a cross-shaped structure, so that the balun element can be inserted into the target gap, and the balun element is vertically fastened to the fastening plate by using the target gap.

3. The antenna element according to claim 1 , wherein a gap structure is provided in a manner of passing through an intermediate location of each dielectric plate, so that the two dielectric plates are embedded into each other in a crossing manner by using the gap structure;

the two signal transmission units are respectively on two sides of the gap structure on the first surface of the dielectric plate; and

the feeding unit is an L-shaped feeding sheet, and the feeding unit is on two sides and at a top end of the gap structure, or the feeding unit is at a bottom end of the gap structure.

4. The antenna element according to claim 1 , wherein the radiating elements and the balun element are integrated into a whole, or the radiating elements are detachably connected to the balun element.

5. The antenna element according to claim 1 , wherein when the second metal piece is disposed at the top end of the first metal piece, the radiating element, the second metal piece, and the first metal piece are successively disposed from top to bottom; and

the filtering module is electrically connected to the radiating element, or the filtering unit is electrically connected to the top end of the signal transmission unit.

6. The antenna element according to claim 1 , wherein when the second metal piece is disposed at the bottom end of the first metal piece, the radiating element, the first metal piece, and the second metal piece are successively disposed from top to bottom; and

the filtering module is electrically connected to the bottom end of the signal transmission unit, or the filtering module is electrically connected to the fastening plate.

7. The antenna element according to claim 1 , wherein the filtering module comprises two second metal pieces, and when the second metal pieces are disposed at the top end and the bottom end of the first metal piece, the radiating element ( 201 ), one of the second metal pieces, the first metal piece, and the other second metal piece are successively disposed from top to bottom; and

the filtering module is electrically connected:

to the radiating element and the fastening plate separately;

to the radiating element and the bottom end of the signal transmission unit separately;

to the top end of the signal transmission unit and the bottom end of the signal transmission unit separately; or

to the top end of the signal transmission unit and the fastening plate separately.

8. The antenna element according to claim 1 , wherein

a length of each radiating element is a quarter of a wavelength corresponding to center frequency of a signal; and

a height of each dielectric plate is a quarter of the wavelength corresponding to the center frequency of the signal.

9. The antenna element according to claim 1 , wherein a length of each of the first metal piece and the second metal piece is between 0.1 time and once as long as a wavelength corresponding to resonance frequency of the signal.