A beam forming network, comprising: a first 180-degree bridge for equal-power division, a 180-degree bridge for unequal-power division, a 90-degree phase shifter, and a second 180-degree bridge for equal-power division, wherein the first 180-degree bridge for equal-power division, the 180-degree bridge for unequal-power division, and the second 180-degree bridge for equal-power division separately have a sum input port, a difference input port, a straight-through port of the sum input port, and a coupling port of the sum input port, wherein the coupling port of the sum input port of the first 180-degree bridge for equal-power division is connected to the difference input port of the 180-degree bridge for unequal-power division, the straight-through port of the sum input port of the first 180-degree bridge for equal-power division is connected to an input port of the 90-degree phase shifter, an output port of the 90-degree phase shifter is connected to the difference input port of the second 180-degree bridge for equal-power division, and the straight-through port of the sum input port of the 180-degree bridge for unequal-power division is connected to the sum input port of the second 180-degree bridge for equal-power division; and two input ports of the first 180-degree bridge for equal-power division and the sum input port of the 180-degree bridge for unequal-power division are configured to receive a signal from a base station transceiver, and the coupling port of the sum input port of the 180-degree bridge for unequal-power division and two output ports of the second 180-degree bridge for equal-power division are configured to feed an antenna array. a first 180-degree bridge for equal-power division, a 180-degree bridge for unequal-power division, a 90-degree phase shifter, and a second 180-degree bridge for equal-power division, wherein the first 180-degree bridge for equal-power division, the 180-degree bridge for unequal-power division, and the second 180-degree bridge for equal-power division separately have a sum input port, a difference input port, a straight-through port of the sum input port, and a coupling port of the sum input port, wherein the coupling port of the sum input port of the first 180-degree bridge for equal-power division is connected to the difference input port of the 180-degree bridge for unequal-power division, the straight-through port of the sum input port of the first 180-degree bridge for equal-power division is connected to an input port of the 90-degree phase shifter, an output port of the 90-degree phase shifter is connected to the difference input port of the second 180-degree bridge for equal-power division, and the straight-through port of the sum input port of the 180-degree bridge for unequal-power division is connected to the sum input port of the second 180-degree bridge for equal-power division; and two input ports of the first 180-degree bridge for equal-power division and the sum input port of the 180-degree bridge for unequal-power division are configured to receive a signal from a base station transceiver, and the coupling port of the sum input port of the 180-degree bridge for unequal-power division and two output ports of the second 180-degree bridge for equal-power division are configured to feed an antenna array.