Antenna system

1. An antenna system, for receiving and transmitting wireless signals, comprising:

a first complex antenna, comprising a first reflection element, a first antenna array and a second antenna array, wherein the first antenna array and the second antenna array are disposed on the first reflection element;

a second complex antenna, comprising a second reflection element, a third antenna array and a fourth antenna array, wherein the third antenna array and the fourth antenna array are disposed on the second reflection element, and the first reflection element and the second reflection element are fixed to form an included angle to each other; and

a feeding device, coupled to the first complex antenna and the second complex antenna, for alternately outputting radio-frequency signals to the first complex antenna and the second complex antenna, to emit wireless signals via the first complex antenna and the second complex antenna, and switching phases of the radio-frequency signals outputted to the first complex antenna and the second complex antenna, to change characteristics of beam generated by the first complex antenna and the second complex antenna in a vertical plane, wherein each of the first antenna array, the second antenna array, the third antenna array, and the fourth antenna array is a 1×4 antenna array, the 1×4 antenna array comprises four unit antennas, the four unit antennas have identical structures and sizes, and each of the four unit antennas comprises at least one radiant section disposed on the first reflection element or the second reflection element, each of a first metal sheet and a second metal sheet of the at least one radiant section comprises a bend, wherein the first metal sheet and the second metal sheet of the at least one radiant section form a diamond dipole antenna structure, the feeding device comprises two feeding module sets, respectively coupled to vertically polarized antennas and horizontally polarized antennas within the first antenna array, the second antenna array, the third antenna array and the fourth antenna array, and each of the two feeding module sets comprises four feeding modules respectively corresponding to the first antenna array, the second antenna array, the third antenna array, and the fourth antenna array, and each feeding module comprises:

a power divider, comprising an input terminal coupled to a signal source, and four output terminals, for distributing radio-frequency signals generated by the signal source to the four output terminals; and

four phase shifters, respectively coupled to one of the four output terminals and one of the four unit antennas, for outputting radio-frequency signals outputted by the power divider to the four unit antennas in a plurality of phase states;

wherein, in one of the plurality of phase states, radio-frequency signals outputted by the four phase shifters have no phase difference, and in other of the plurality of phase states, radio-frequency signals outputted by the four phase shifters have phase difference;

wherein the four phase shifters are respectively switched between at least two phase shift modes, to switch the phases of the radio-frequency signals outputted to the first complex antenna and the second complex antenna.

2. The antenna system of claim 1 , wherein the included angle is in a range of 70 degrees to 150 degrees.

3. The antenna system of claim 1 , wherein each of the four phase shifters comprises:

a low-pass filter, coupled to the unit antenna, corresponding to one of the at least two phase shift modes;

a high-pass filter, coupled to the unit antenna, corresponding to another one of the at least two shift modes; and

a switch, coupled to the low-pass filter and the high-pass filter, for outputting the radio-frequency signals outputted by the power divider to one of the low-pass filter and the high-pass filter.

4. The antenna system of claim 1 , wherein each of the feeding module sets further comprises:

a first switching circuit, comprising an input terminal coupled to a first signal source, and two output terminals coupled to two feeding modules corresponding to the first antenna array and the third antenna array within the four feeding modules, for switching the input terminal to connect to one of the two output terminals; and

a second switching circuit, comprising an input terminal coupled to a second signal source, and two output terminals coupled to two feeding modules corresponding to the second antenna array and the fourth antenna array within the four feeding modules, for switching the input terminal to connect to one of the two output terminals.

5. The antenna system of claim 4 , wherein when the first switching circuit connects the first signal source and a feeding module corresponding to the first antenna array within the four feeding modules, the second switching circuit connects the second signal source and a feeding module corresponding to the second antenna array within the four feeding module; and when the first switching circuit connects the first signal source and a feeding module corresponding to the third antenna array within the four feeding module, the second switching circuit connects the second signal source and a feeding module corresponding to the fourth antenna array within the four feeding module.

6. The antenna system of claim 1 , wherein each of the unit antennas further comprises:

a reflection plate, disposed on the at least one radiant section, having a shape with symmetry.