CN115728999A - Terahertz liquid crystal phase shifter - Google Patents
Terahertz liquid crystal phase shifter Download PDFInfo
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- CN115728999A CN115728999A CN202211440053.6A CN202211440053A CN115728999A CN 115728999 A CN115728999 A CN 115728999A CN 202211440053 A CN202211440053 A CN 202211440053A CN 115728999 A CN115728999 A CN 115728999A
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- 239000004973 liquid crystal related substance Substances 0.000 title claims abstract description 70
- 239000000758 substrate Substances 0.000 claims abstract description 32
- 230000005684 electric field Effects 0.000 claims abstract description 14
- 239000002184 metal Substances 0.000 claims abstract description 11
- 230000010363 phase shift Effects 0.000 claims abstract description 6
- 238000002347 injection Methods 0.000 claims description 6
- 239000007924 injection Substances 0.000 claims description 6
- 210000002858 crystal cell Anatomy 0.000 claims description 2
- 238000000034 method Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000001902 propagating effect Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Abstract
The invention discloses a terahertz liquid crystal phase shifter, which comprises a metal waveguide plate, a dielectric strip and two substrates, wherein the inner sides of the two substrates are respectively provided with an electrode, the electrodes comprise a left electrode, a middle electrode and a right electrode, and when an upper electrode uniformly applies positive voltage and a lower electrode is uniformly grounded, an electric field in an orthogonal direction is formed between the two substrates; when the middle electrode is not electrified, one pair of the left electrode or the right electrode is applied with positive voltage, and the other pair is grounded, an electric field in the orthogonal direction is formed between the substrates; the phase shifter uses three pairs of electrodes to realize parallel and orthogonal electric field directions, realizes continuous change of liquid crystal dielectric constant, and further realizes continuously adjustable excellent phase shift characteristics.
Description
Technical Field
The invention relates to the technical field of phased array radar antennas, in particular to a terahertz liquid crystal phase shifter.
Background
At present, most of tunable phase shifters applicable to phased array antennas are implemented by semiconductor technology and micro-electromechanical systems, the semiconductor consumes much power, and the micro-electromechanical systems are severely worn and can only provide a small and discrete phase shift.
Chinese patent CN114094338A discloses a 4 × 4 thz phased array antenna based on a liquid crystal waveguide phase shifter, and specifically discloses a liquid crystal waveguide phase shifter, which adopts a structure with two electrodes, as shown in fig. 1, two electrodesThe liquid crystal material is filled between the electrode plates, the upper electrode plate is connected with positive voltage, the lower electrode plate is grounded, and an electric field is formed by applying voltage to the electrode plates. When no voltage is applied, the liquid crystal molecules are parallel to the substrate and are affected by the orientation layer, and the dielectric constant is v ┴ (ii) a When a certain value of voltage is applied, the liquid crystal molecules begin to deflect along the direction of an electric field, and the deflection degree and the voltage are in positive correlation; when a peak voltage is applied, the liquid crystal molecules are not deflected any more even if the voltage is further increased, and the liquid crystal molecules are aligned perpendicular to the substrates and have a dielectric constant of ε ‖ 。
The phase shifter performance based on liquid crystal materials depends on the complete dielectric anisotropy of the liquid crystal (Δ ∈ = ∈) ‖ -ε ┴ ) If and only if the liquid crystal dielectric constant is achieved from ε ┴ To epsilon ‖ The liquid crystal performance reaches the optimum, epsilon ‖ By applying a voltage to form an electric field, with initial epsilon ┴ This is achieved only by applying an alignment agent and forming an alignment film. The liquid crystal phase shifter coated with the aligning agent realizes continuous tuning of liquid crystal dielectric constant (from epsilon) ┴ To epsilon ‖ ) However, the whole pressurization process is not reversible, and can not be realized from epsilon ‖ To epsilon ┴ The recovery process of (1).
Disclosure of Invention
In order to solve the problems, the inventor provides a terahertz liquid crystal phase shifter based on a non-radiative dielectric waveguide, and the terahertz liquid crystal phase shifter has the advantages of high precision, continuous adjustability, low power consumption, low cost and the like. The compact design idea of the liquid crystal medium phase shifter and the bias electrode network is realized by adopting two half metal waveguides, and meanwhile, the cost of the phase shifter is greatly reduced by utilizing a block processing technology, the stable dielectric property in a terahertz frequency band is ensured, the low-power consumption and the low-loss conduction of electromagnetic waves are realized, and the application range of the tunable phase shifter in the field of wireless communication is widened.
A terahertz liquid crystal phase shifter comprises a metal waveguide plate, a dielectric strip and two substrates, wherein electrodes are arranged on the inner sides of the two substrates, and each electrode comprises a left electrode, a middle electrode and a right electrode; when the upper layer electrodes of the electrodes are uniformly applied with positive voltage and the lower layer electrodes are uniformly grounded in a state A, the two substrates are respectively provided with a positive electrode and a negative electrodeAn electric field is formed in the orthogonal direction, and the dielectric constant of the liquid crystal is epsilon ┴ (ii) a (ii) a When the liquid crystal display is in a state B in which the middle electrode is not energized and one of the left electrode and the right electrode is applied with a positive voltage and the other is grounded, an electric field in the orthogonal direction is formed between the two substrates, and the dielectric constant of the liquid crystal at that time is ε ‖ 。
Furthermore, the continuous change of the dielectric constant of the liquid crystal is realized through the numerical value change of the voltages in the A state and the B state, and further the continuously adjustable excellent phase shift characteristic is realized.
Furthermore, the dielectric strip is formed by bonding a first body and a second body, three liquid crystal grooves are formed in the first body and the second body, and after the first body and the second body are bonded, the two corresponding half liquid crystal grooves are combined to form a liquid crystal cavity.
Furthermore, liquid crystal injection holes are formed in the first body/the second body, and the number of the liquid crystal injection holes is the same as that of the liquid crystal cavities.
Further, the left electrode and the right electrode are slotted elliptical electrodes.
Further, the middle electrode is an electrode corresponding to the shape of the liquid crystal groove.
Compared with the prior art, the invention has the following beneficial effects:
(1) Three pairs of electrodes are used for realizing parallel and orthogonal electric field directions, so that the continuous change of the dielectric constant of the liquid crystal is realized, and the continuously adjustable excellent phase shift characteristic is further realized.
(2) The packaging procedure of the current common liquid crystal phase shifter comprises the steps of coating an orientation agent, uniformly rubbing, curing, baking, plugging a gasket and filling liquid crystal.
Drawings
Fig. 1 is a schematic structural diagram of a terahertz liquid crystal phase shifter in embodiment 1;
FIG. 2 is a schematic structural view of a metallic waveguide plate in example 1;
fig. 3 is a side view of a terahertz liquid crystal phase shifter in embodiment 1;
FIG. 4 is a schematic view of the construction of a dielectric strip in example 1;
FIG. 5 is an exploded view of the dielectric strip of example 1;
FIG. 6 is a schematic view of an electrode network in example 1;
fig. 7 is a schematic diagram of the electric field distribution of the liquid crystal tuning control in example 1.
Reference numerals are as follows:
1-a metallic waveguide plate; 2-a substrate; 3-a left electrode; 4-a middle electrode; 5-a right electrode; 6-a dielectric strip; 61-a first body; 62-a second body; 63-a liquid crystal injection hole; 7-a liquid crystal cavity; 71-liquid crystal cell.
Detailed Description
The present invention will be described in further detail with reference to the following detailed description and accompanying drawings.
Example 1
As shown in fig. 1-3, this embodiment discloses a terahertz liquid crystal phase shifter, which includes a metal waveguide plate 1, a dielectric strip 6 and two substrates 2, wherein a bias electrode network is disposed on the substrate 2, and the two half metal waveguide plates 1 are configured to clamp the dielectric strip 6 and the two substrates 2 in a middle groove formed by combining the two metal waveguide plates 1 in an up-down covering manner, so as to form a whole. The grooves at the left end and the right end of the metal waveguide plate 1 are used for transmitting terahertz electromagnetic waves and bearing the input end and the output end of the phase shifter, and due to the close fit of the metal waveguide plate 1, the electromagnetic waves can be only input from the input end of the phase shifter and only output from the output end of the phase shifter, so that the electromagnetic waves in the phase shifter can be effectively prevented from radiating outside the waveguide.
As shown in fig. 4-5, the dielectric strip 6 is a Rexolite 1422 dielectric strip, a unique cross-linked polystyrene, with a dielectric constant of 2.53 (to 500 GHz). The dielectric strip 6 is horizontally divided into an upper half and a lower half from the middle, namely a first body 61 and a second body 62, liquid crystal grooves 71 are dug in the first body 61 and the second body 62 respectively, liquid crystal injection holes 63 are drilled in one half of the first body 61 and the second body 62, finally the dielectric strip 6 is formed by utilizing plastic cement, the interval between the three liquid crystal grooves 71 is 2mm, the size is 4mm multiplied by 2mm multiplied by 0.254mm, and two ends of the dielectric strip 6 respectively have 2mm which extends into two end grooves of the non-radiative dielectric waveguide so as to reduce the terahertz wave transmission loss at a node. Because the liquid crystal has good viscosity, air bubbles are inevitably generated during pouring, and the existence of the air bubbles seriously influences the realization of the complete dielectric anisotropy of the liquid crystal and increases the transmission loss of devices, the three liquid crystal cavities 7 are respectively poured with the liquid crystal through respective liquid crystal filling holes 63 during pouring of the liquid crystal, thereby avoiding the problem that the bubbles are generated due to the pouring of a single filling hole.
As shown in fig. 6, the substrate 2 is an FR-4 substrate, the thickness of the FR-4 substrate is 0.3mm, the distance between the upper and lower substrates 2 is 1mm, the metal electrode patches of the bias electrode network are etched on the inner side of the substrate, and the bonding pads on the substrate 2 are connected with an external voltage source by using low-frequency connecting wires to provide bias voltage. The bias electrode network is as shown in fig. 5, the pads on the substrate 2 are connected with an external voltage source by using low frequency connecting wires to provide bias voltage, the three pads are connected with the electrodes by feeder lines, wherein the left electrode 3 and the right electrode 5 on the upper and lower substrates 2 are respectively provided with three sub-electrodes, all the pads, feeder lines and electrodes are metal patches with the thickness of 0.035mm etched on the substrate 2, the etched electrodes on the lower side of the upper substrate and the upper side of the lower substrate are rotated by 180 degrees to avoid the pads of the middle electrode 4 being positioned in the same direction, thereby possibly causing short circuit. The upper and lower substrates 2 are fixed by screw screws.
Since the electrodes are placed inside the metallic waveguide plate 1 and the propagating electromagnetic waves are coupled into the electrodes, resonance and leakage that seriously affect the propagation are caused, and the transmission efficiency is lowered, so that their influence on the propagating radio frequency mode must be minimized. For a simple straight bias line, parasitic modes are excited. In order to avoid the situation, all the electrodes are grooved to inhibit resonance, the outer left electrode 3 and the outer right electrode 5 are in an elliptical structure to achieve the best performance, and two electrodes at two ends in the middle electrode 4 are designed to be conical to reduce propagation interference at two ends of the input and output of the phase shifter. In addition, the stub design also avoids the radio frequency leakage of the direct current power line. The electrode network utilizes design methods such as stub lines, slots, elliptical electrodes and the like, and resonance and leakage influences of the electrode pair on the propagation process are reduced to the greatest extent
As shown in FIG. 7, when a positive voltage is applied to the upper electrodes and the lower electrodes are grounded, an electric field in the orthogonal direction is formed between the two substrates, and the dielectric constant of the liquid crystal is ε ┴ (ii) a When the middle electrode is not energized, a positive voltage is applied to one of the left electrode and the right electrode, and the other pair is grounded, an electric field in the orthogonal direction is formed between the substrates, and the dielectric constant of the liquid crystal is epsilon ‖ . Through the voltage value change of the two states, the continuous change of the liquid crystal dielectric constant can be realized, and the continuously adjustable excellent phase shift characteristic is further realized.
The present invention has been described in terms of specific examples, which are provided to aid in understanding the invention and are not intended to be limiting. Numerous simple deductions, modifications or substitutions may also be made by those skilled in the art in light of the present teachings.
Claims (6)
1. A terahertz liquid crystal phase shifter comprises a metal waveguide plate, a dielectric strip and two substrates, wherein electrodes are arranged on the inner sides of the two substrates, and the terahertz liquid crystal phase shifter is characterized in that the electrodes comprise a left electrode, a middle electrode and a right electrode; when the upper electrode of the electrode is uniformly applied with positive voltage and the lower electrode of the electrode is uniformly grounded in a state A, an electric field in the orthogonal direction is formed between the two substrates; in a state B where the middle electrode is not energized and one of the left or right electrodes is applied with a positive voltage and the other is grounded, an electric field in an orthogonal direction is formed between the two substrates.
2. The terahertz liquid crystal phase shifter of claim 1, wherein continuous change of liquid crystal dielectric constant is realized through numerical value change of the voltages of the A state and the B state, and further excellent phase shift characteristics which are continuously adjustable are realized.
3. The terahertz liquid crystal phase shifter of claim 1, wherein the dielectric strip is formed by bonding a first body and a second body, the first body and the second body are respectively provided with three liquid crystal grooves, and after the first body and the second body are bonded, the two corresponding liquid crystal grooves are combined into a liquid crystal cavity.
4. The terahertz liquid crystal phase shifter according to claim 3, wherein the first body/the second body are provided with liquid crystal injection holes, and the number of the liquid crystal injection holes is the same as the number of the liquid crystal cavities.
5. The terahertz liquid crystal phase shifter of any one of claims 1-4, wherein the left and right electrodes are slotted elliptical electrodes.
6. The terahertz liquid crystal phase shifter of any one of claims 1-4, wherein the middle electrode is an electrode corresponding to the shape of the liquid crystal cell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211440053.6A CN115728999A (en) | 2022-11-17 | 2022-11-17 | Terahertz liquid crystal phase shifter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211440053.6A CN115728999A (en) | 2022-11-17 | 2022-11-17 | Terahertz liquid crystal phase shifter |
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| CN115728999A true CN115728999A (en) | 2023-03-03 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101142713A (en) * | 2005-03-18 | 2008-03-12 | 索尼德国有限责任公司 | Bar shaped antenna and method of operating the bar shaped antenna |
| CN111293425A (en) * | 2020-03-24 | 2020-06-16 | 北京华镁钛科技有限公司 | Liquid crystal active phased array antenna |
| CN112510372A (en) * | 2020-12-10 | 2021-03-16 | 电子科技大学 | Terahertz phased array antenna based on liquid crystal medium phase shifter |
| CN114094338A (en) * | 2021-10-22 | 2022-02-25 | 电子科技大学 | 4X 4 terahertz phased-array antenna based on liquid crystal waveguide phase shifter |
| CN114839816A (en) * | 2022-06-20 | 2022-08-02 | 深圳秋田微电子股份有限公司 | Liquid crystal phase shifter and liquid crystal antenna |
-
2022
- 2022-11-17 CN CN202211440053.6A patent/CN115728999A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101142713A (en) * | 2005-03-18 | 2008-03-12 | 索尼德国有限责任公司 | Bar shaped antenna and method of operating the bar shaped antenna |
| US20090231221A1 (en) * | 2005-03-18 | 2009-09-17 | Sony Deutschland Gmbh | Dielectric rod antenna and method for operating the antenna |
| CN111293425A (en) * | 2020-03-24 | 2020-06-16 | 北京华镁钛科技有限公司 | Liquid crystal active phased array antenna |
| CN112510372A (en) * | 2020-12-10 | 2021-03-16 | 电子科技大学 | Terahertz phased array antenna based on liquid crystal medium phase shifter |
| CN114094338A (en) * | 2021-10-22 | 2022-02-25 | 电子科技大学 | 4X 4 terahertz phased-array antenna based on liquid crystal waveguide phase shifter |
| CN114839816A (en) * | 2022-06-20 | 2022-08-02 | 深圳秋田微电子股份有限公司 | Liquid crystal phase shifter and liquid crystal antenna |
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Application publication date: 20230303 |