A balanced dipole unit for use in a broadband omnidirectional collinear array antenna, wherein the balanced dipole unit comprises: a circuit carrier, a balanced dipole unit circuit, a feeder and a ground wire; the balanced dipole unit circuit forming a closed loop circuit, the balanced dipole unit comprising a first circuit portion symmetrically arranged on the front of the circuit carrier and a second circuit portion symmetrically arranged on the back of the circuit carrier; and the feeder and the ground wire are connected to the balanced dipole unit circuit, and the feeder and the ground wire are symmetrically distributed in the balanced dipole unit, wherein the first circuit portion includes three antenna circuit lines which are sequentially symmetrically arranged on the front of the circuit carrier, wherein one antenna circuit line in the three antenna circuit lines overlaps with a center line of the circuit carrier, the remaining two antenna circuit lines are symmetrically distributed based on the antenna circuit line overlapping with the center line, and each antenna circuit line is respectively parallel to the antenna circuit line overlapping with the center line, wherein the three antenna circuit lines are each symmetrical based on a vertical line of the front of the circuit carrier perpendicular to the center line of the front of the circuit carrier, wherein the second circuit portion includes a first sub-circuit and a second sub-circuit, wherein the first sub-circuit and the second sub-circuit are symmetrically distributed based on a center point on the back of the circuit carrier, and wherein each sub-circuit itself is symmetrical based on a center line on the back of the circuit carrier, and wherein the first sub-circuit and the second sub-circuit form a closed-loop circuit through the antenna circuit line in the first circuit portion. wherein the balanced dipole unit comprises: a circuit carrier, a balanced dipole unit circuit, a feeder and a ground wire; the balanced dipole unit circuit forming a closed loop circuit, the balanced dipole unit comprising a first circuit portion symmetrically arranged on the front of the circuit carrier and a second circuit portion symmetrically arranged on the back of the circuit carrier; and the feeder and the ground wire are connected to the balanced dipole unit circuit, and the feeder and the ground wire are symmetrically distributed in the balanced dipole unit, wherein the first circuit portion includes three antenna circuit lines which are sequentially symmetrically arranged on the front of the circuit carrier, wherein one antenna circuit line in the three antenna circuit lines overlaps with a center line of the circuit carrier, the remaining two antenna circuit lines are symmetrically distributed based on the antenna circuit line overlapping with the center line, and each antenna circuit line is respectively parallel to the antenna circuit line overlapping with the center line, wherein the three antenna circuit lines are each symmetrical based on a vertical line of the front of the circuit carrier perpendicular to the center line of the front of the circuit carrier, wherein the second circuit portion includes a first sub-circuit and a second sub-circuit, wherein the first sub-circuit and the second sub-circuit are symmetrically distributed based on a center point on the back of the circuit carrier, and wherein each sub-circuit itself is symmetrical based on a center line on the back of the circuit carrier, and wherein the first sub-circuit and the second sub-circuit form a closed-loop circuit through the antenna circuit line in the first circuit portion.