This application is based on International Application No. PCT/CN2019/087674 filed on May 21, 2019, which claims priority to Chinese Patent Application No. 201810806844.3, filed on Jul. 18, 2018 and titled with “LIQUID CRYSTAL PHASE SHIFTER AND ANTENNA”, the content of which is incorporated herein by reference in their entireties.
The present disclosure relates to the field of electromagnetic wave, and in particular, to a liquid crystal phase shifter and an antenna.
A phase shifter is a device that can adjust a phase of an electromagnetic wave, and such a phase shifter is widely used in the fields such as radars, spacecraft attitude control, accelerators, communication, instruments, and even in the music field.
New liquid crystal phase shifters have been emerging with the advance in technology. However, in current designs of liquid crystal phase shifter, carrier frequencies of the liquid crystal phase shifter are fixed and can only be adjusted by creating a new liquid crystal phase shifter. That is, the liquid crystal phase shifters have relatively poor compatibility.
Embodiments of the present disclosure provide a liquid crystal phase shifter and an antenna, which can adjust carrier frequencies applicable to the liquid crystal phase shifter, thereby improving the compatibility of the liquid crystal phase shifter.
In one aspect, an embodiment of the present disclosure provides a liquid crystal phase shifter, including: a first substrate and a second substrate opposite to each other; a liquid crystal layer between the first substrate and the second substrate; and at least one phase-shifting unit. Each of the at least one phase-shifting unit comprises a microstrip line and a phase-controlled electrode, the microstrip line is located between the first substrate and the liquid crystal layer, the phase-controlled electrode is located between the second substrate and the liquid crystal layer, the microstrip line comprises a plurality of sub-microstrip lines, each of the sub-microstrip lines comprises a transmission portion having two ends, and one end of the two ends of one sub-microstrip line of any two adjacent sub-microstrip lines of the plurality of sub-microstrip lines is the same as one end of the two ends of another one sub-microstrip line of the any two adjacent sub-microstrip lines. The phase-shifting unit further includes feed terminals each corresponding to one of the ends, the feed terminals are located on a side of the first substrate facing away from the second substrate or on a side of the second substrate facing away from the first substrate, and in a direction perpendicular to a plane of the first substrate, each of the feed terminals overlaps a corresponding one of the two ends.
In another aspect, an embodiment of the present disclosure further provides an antenna including a liquid crystal phase shifter. The liquid crystal phase shifter includes a first substrate and a second substrate opposite to each other; a liquid crystal layer between the first substrate and the second substrate; and at least one phase-shifting unit. Each of the at least one phase-shifting unit comprises a microstrip line and a phase-controlled electrode, the microstrip line is located between the first substrate and the liquid crystal layer, the phase-controlled electrode is located between the second substrate and the liquid crystal layer, the microstrip line comprises a plurality of sub-microstrip lines, each of the sub-microstrip lines comprises a transmission portion having two ends, and one end of the two ends of one sub-microstrip line of any two adjacent sub-microstrip lines of the plurality of sub-microstrip lines is the same as one end of the two ends of another one sub-microstrip line of the any two adjacent sub-microstrip lines. The phase-shifting unit further includes feed terminals each corresponding to one of the ends, the feed terminals are located on a side of the first substrate facing away from the second substrate or on a side of the second substrate facing away from the first substrate, and in a direction perpendicular to a plane of the first substrate, each of the feed terminals overlaps a corresponding one of the two ends.
In order to explain technical solutions of embodiments of the present disclosure, the accompanying drawings used in the embodiments are briefly described below. The drawings merely illustrate a part of the embodiments of the present disclosure. Based on these drawings, those skilled in the art can obtain other drawings without any creative efforts.
In order to explain the technical solutions of the present disclosure, the embodiments of the present disclosure are described in details with reference to the drawings, where like features are denoted by the same reference label throughout the drawings and throughout the specification description. It should be understood that the described embodiments are merely parts of, rather than all of the embodiments of the present disclosure. Any other embodiments obtained by those skilled in the art without paying creative labor shall fall into the protection scope of the present disclosure.
The terms used in the embodiments of the present disclosure are merely for the purpose of describing particular embodiments, but are not intended to limit the present disclosure. Unless otherwise noted in the context, the singular form expressions “a”, “an”, “the” and “said” used in the embodiments and appended claims of the present disclosure are also intended to indicate a plural form.
Specifically, during the operation of the liquid crystal phase shifter, a voltage signal is applied to the microstrip line 41 and the phase-controlled electrode 42 to form an electric field between the microstrip line 41 and the phase-controlled electrode 42, and the electric field drives the liquid crystals in the liquid crystal layer 3 to be deflected. The microstrip line 41 is configured to transmit a microwave signal between the microstrip line 41 and the phase-controlled electrode 42. During the transmission of the microwave signal, a phase changes with the deflection of the liquid crystals, achieving a phase-shifting function of the microwave signal. The phase-shifting of the microwave is a change of electrical characteristics of the deflected liquid crystals, and a carrier frequency applicable to the phase-shifting unit is related to a distance transmitted by the microwave in the deflected liquid crystals. In the embodiment of the present disclosure, the transmission portion 412 is configured to transmit the microwave signal and perform the phase-shifting during the transmission process, and the feed terminal 43 is configured to input and output the microwave signal on the microstrip line 41 by cooperating with the ends of the microstrip line 41. In the embodiment of the present disclosure, the microstrip line 41 includes at least two sub-microstrip lines 410. Each of the two sub-microstrip lines 410 includes two ends 411 and a transmission portion 412 connected between the two ends 411, and each of the two ends 411 can be correspondingly provided with one feed terminal 43. The microstrip line 41 includes at least three feed terminals 43. When the liquid crystal phase shifter operates, any two of the at least three feed terminals 43 can be used as an actual input feed terminal and an actual output feed terminal respectively. When selecting to use different feed terminals 43, transmission distances of the microwave transmitted on the microstrip line 41 are different, which results in different effective path lengths of the phase-shifting of the microwave caused by the deflected liquid crystals during the microwave transmission. That is, the liquid crystal phase shifter can be adapted to different carrier frequencies. For example, the liquid crystal phase shifter shown in
In the liquid crystal phase shifter according to the embodiment of the present disclosure, the microstrip lines of the liquid crystal phase shifter correspond to at least three feed terminals. When the liquid crystal phase shifter operates, any two of the at least three feed terminals can be selected as an actual input feed terminal and an actual output feed terminal. When using different feed terminals, the transmission distances of the microwave on the microstrip lines are different, which results in different effective path lengths of the phase-shifting of the microwave caused by the deflected liquid crystals during the microwave transmission. That is, the liquid crystal phase shifter can be adapted to different carrier frequencies. However, in the related art, the microstrip lines of the liquid crystal phase shifter only correspond to two feed terminals, and the applicable carrier frequency cannot be adjusted. Therefore, the embodiments of the present disclosure improve the compatibility of the liquid crystal phase shifter.
In one embodiment, as shown in
Specifically, in an example of positive liquid crystal molecules, in the non-operating state, no electric field is formed between the phase-controlled electrode 42 and the microstrip line 41 in the liquid crystal phase shifter, and long axes of the liquid crystal molecules in the liquid crystal layer 3 extend and are arranged along the initial alignment direction x of the liquid crystal layer. In the operating state, the electric field is formed between the phase-controlled electrode 42 and the microstrip line 41 in the liquid crystal phase shifter, the liquid crystals between the phase-controlled electrode 42 and the microstrip line 41 are deflected, and the microwave transmitted along the extending path of the microstrip line 41 is phase-shifted due to the change in the electrical characteristics of the deflected liquid crystal. The transmission paths of the microwave are represented by the dotted arrows in
It should be noted that the initial alignment direction x of the liquid crystal layer is not limited to that shown in the drawings, and other directions are also possible, as long as the effective segment 401 dominates the adjustment of the phase of the microwave signal. The initial alignment direction x of the liquid crystal layer can be set by the liquid crystal orientation layer. For example, as shown in
In one embodiment, each effective segment 401 has the same length, and thus multiples of the effective path length of the microwave phase-shifting can be selected by selecting different feed terminals 43. For example, the length of each effective segment 401 is L, as shown in
In one embodiment, the non-effective segments 402 extend in the same direction, which can form a serpentine transmission portion 412 and utilizes the space more efficiently.
In one embodiment, the extending direction of each non-effective segment 402 is perpendicular to the initial alignment direction x of the liquid crystal layer, so as to ensure that the deflection of the liquid crystals corresponding to the non-effective segment 402 will not cause the liquid crystal phase-shifting. In this way, the effective path length of the phase-shifting of the microwave can be more accurately adjusted.
In one embodiment, a U-shaped structure is formed by any two adjacent effective segments 401 and the non-effective segment 402 that connects the two adjacent effective segments 401.
In one embodiment,
Specifically, in the structure of the liquid crystal phase shifter shown in
In one embodiment, as shown
In one embodiment, as shown
In one embodiment, as shown
For example, as shown in
In one embodiment, as shown in
In one embodiment, as shown in
Specifically, during the operation of the liquid crystal phase shifter, only the liquid crystals corresponding to the part of the microstrip line 41 covered by the phase-controlled electrode 42 will be deflected, so as to exert the liquid crystal phase shift function at a position corresponding to the effective segment 401. Theoretically, the non-effective segment 402 of the transmission portion 412 is unnecessarily covered by the phase-controlled electrode 42. However, the phase-controlled electrode 42 may cover the entire transmission portion 412 in order to reduce process difficulty of the phase-controlled electrode 42. In addition, it should be noted that in the structure shown in
It should be noted that, in the liquid crystal phase shifter in the embodiment of the present disclosure, only one phase-shifting unit 4 is illustrated. In other implementable embodiments, one liquid crystal phase shifter includes a plurality of phase-shifting units distributed in an array, and the phase-controlled electrodes of the plurality of phase-shifting units are connected to each other in such a manner that all the phase-controlled electrodes have the same potential. Each phase-shifting unit is configured to exert the phase-shifting function of one microwave signal. Each phase-shifting unit can be fabricated as a different liquid crystal cell, and it is also possible to fabricate all the phase-shifting units into the same one liquid crystal cell. In addition, in the embodiment of the present disclosure, the feed terminal 43 may be a part of the feeder, and the feeder is configured to transmit the microwave signal between the feed terminal 43 and other components. For example, in an application scenario of an antenna, a radiating unit of the antenna is connected to the feed terminal 43 through the feeder, after the liquid crystal phase shifter completes the phase-shifting, the microwave signal is fed from the microstrip line 41 to the feed terminal 43, the feed terminal 43 transmits the phase-shifted microwave signal to the radiating unit through the feeder, and the radiating unit radiates the microwave signal to exert an antenna function.
An embodiment of the present disclosure further provides an antenna including the above liquid crystal phase shifter. The liquid crystal phase shifter is configured to exert the phase-shifting function of the microwave signal in the antenna.
The specific structure and principle of the liquid crystal phase shifter are the same as those in the above embodiment, which will not be repeated herein.
In the antenna according to the embodiment of the present disclosure, the microstrip line of the liquid crystal phase shifter corresponds to at least three feed terminals. When the liquid crystal phase shifter operates, any two of the at least three feed terminals can be selected as an actual input feed terminal and an actual output feed terminal. When using different feed terminals, the microstrip lines have different microwave transmission distances. When the microwave transmission distances are different, the effective path lengths of the phase-shifting of the microwave by the deflected liquid crystal can be different during microwave transmission. That is, the liquid crystal phase shifter can be adapted to different carrier frequencies. However, in the related art, the microstrip line of the liquid crystal phase shifter only corresponds to two feed terminals, and the applicable carrier frequency cannot be adjusted. Therefore, the embodiments of the present disclosure improve the compatibility of the liquid crystal phase shifter.
Number | Date | Country | Kind |
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201810806844.3 | Jul 2018 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2019/087674 | 5/21/2019 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2020/015449 | 1/23/2020 | WO | A |
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