Liquid crystal antenna unit, liquid crystal phased array antenna and phase calibration method

1. A liquid crystal antenna unit, comprising:

a first substrate;

a second substrate disposed opposite to the first substrate;

a liquid crystal layer disposed between the first substrate and the second substrate;

an antenna unit disposed on a side of the first substrate facing away from the liquid crystal layer; and

an antenna control unit disposed corresponding to the antenna unit and configured to control ON/OFF of the antenna unit,

wherein the liquid crystal antenna unit further comprises a third substrate; wherein

the third substrate is disposed on the side of the first substrate facing away from the liquid crystal layer; and

the antenna unit is disposed on the third substrate.

2. The liquid crystal antenna unit according to claim 1 , wherein the antenna unit is disposed on a side of the third substrate facing away from the liquid crystal layer, and the antenna control unit is disposed on a side of the third substrate facing toward the liquid crystal layer.

3. The liquid crystal antenna unit according to claim 1 , wherein the antenna unit is disposed on a side of the third substrate facing toward the liquid crystal layer, and the antenna control unit is disposed on a side of the third substrate facing away from the liquid crystal layer.

4. The liquid crystal antenna unit according to claim 1 , wherein the antenna unit and the antenna control unit are both disposed on a side of the third substrate facing away from the liquid crystal layer; or

the antenna unit and the antenna control unit are both disposed on a side of the third substrate facing toward the liquid crystal layer.

5. The liquid crystal antenna unit according to claim 4 , wherein the first substrate, the second substrate, and the third substrate are each made of glass.

6. The liquid crystal antenna unit according to claim 5 , wherein the antenna control unit comprises an RF switch.

7. The liquid crystal antenna unit according to claim 6 , wherein the RF switch is an RF MEMS switch comprising: a vibration film layer, two insulation layers at two ends of the vibration film layer, and two RF signal transmission lines disposed corresponding to the two insulation layers one by one and positioned in the same plane, wherein each of the insulation layers is clamped between the vibration film layer and one of the RF signal transmission lines, and

when a control voltage is applied to the RF MEMS switch, the vibration film layer of the RF MEMS switch is deformed to a position between the two RF signal transmission lines so that the RF MEMS switch is turned on.

8. The liquid crystal antenna unit according to claim 4 , further comprising a transmission line located between the first substrate and the liquid crystal layer or between the second substrate and the liquid crystal layer.

9. A liquid crystal phased array antenna, comprising a plurality of liquid crystal antenna units according to claim 1 arranged in an array.

10. The liquid crystal phased array antenna according to claim 9 , wherein the first substrates of the plurality of liquid crystal antenna units belong to the same substrate, and the second substrates of the plurality of liquid crystal antenna units belong to the same substrate.

11. The liquid crystal phased array antenna according to claim 9 , wherein the liquid crystal antenna unit further comprises a third substrate; wherein

the third substrate is disposed on the side of the first substrate facing away from the liquid crystal layer; and

the antenna unit is disposed on the third substrate; and

the third substrates of the plurality of liquid crystal antenna units belong to the same substrate.

12. The liquid crystal phased array antenna according to claim 9 , wherein the RF switch is an RF MEMS switch comprising: a vibration film layer, two insulation layers at two ends of the vibration film layer, and two RF signal transmission lines disposed corresponding to the two insulation layers one by one and positioned in the same plane, wherein each of the insulation layers is clamped between the vibration film layer and one of the RF signal transmission lines, and

ion lines so that the RF MEMS switch is turned on; and the transmission lines of the plurality of liquid crystal antenna units belong to the same transmission line.

13. A phase calibration method of a liquid crystal phased array antenna, the liquid crystal phased array antenna being the liquid crystal phased array antenna according to claim 9 , and the phase calibration method comprising:

sequentially taking each of the antenna units in the liquid crystal phased array antenna as an antenna unit to be calibrated, and executing the following steps:

controlling the antenna unit to be calibrated to be ON by the corresponding antenna control unit thereof;

controlling the rest antenna units to be OFF by the corresponding antenna control units thereof, respectively, wherein the rest antenna units comprise all the antenna units except the antenna unit to be calibrated;

testing a phase of an RF signal radiated from the antenna unit to be calibrated by a phase testing device; and

executing the following steps after the phase of the RF signal radiated from each of the antenna units is tested:

carrying out phase calibration on each of the antenna units by a phase shifter, wherein the phase shifter comprises the first substrate, the liquid crystal layer and the second substrate.