CN217821160U - Terahertz modulation unit, terahertz modulator and radar transmitting system - Google Patents
Terahertz modulation unit, terahertz modulator and radar transmitting system Download PDFInfo
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Abstract
The utility model provides a terahertz modulation unit, terahertz modulator and radar transmitting system now, wherein terahertz modulation unit now includes: high electron mobility transistors and super surface structures; the high electron mobility transistor comprises a body, a source electrode, a drain electrode and a grid electrode, and is used for forming two-dimensional electron gas with different concentrations between the source electrode and the drain electrode according to different voltages applied by the grid electrode; the super-surface structure is used for emitting a target frequency wave in incident terahertz waves with different frequencies to a target direction according to two-dimensional electron gas with different concentrations. Through the terahertz modulation unit, the terahertz modulator and the radar transmitting system provided by the embodiment of the utility model, light in a wider terahertz wave range can be modulated, and strong modulation effect on light waves under terahertz frequency is realized, so that a radar scanning visual angle adopting the terahertz modulation unit is enlarged; in addition, the terahertz modulation unit also has the advantages of simple structure, low cost, small volume, light weight and the like.
Description
Technical Field
The utility model relates to a terahertz technical field particularly, relates to a terahertz modulation unit, terahertz modulator and radar transmitting system now.
Background
Common radar beam scanning modes include mechanical scanning and non-mechanical scanning. The mechanical scanning radar has large volume and heavy weight, and because the mechanical motion mechanism has inertia, the control precision is low, and the scanning speed is also limited by the mechanism; at the same time, mechanical parts can be worn, further affecting radar performance. Therefore, non-mechanical scanning radars are commonly used instead of mechanical scanning radars, and a common method is phased array scanning radars. The phased array is a directional antenna formed by arranging a plurality of radiation units in an array form, and the radiation energy and the phase between the units can be controlled; by intensifying the intensity of the electromagnetic wave in a given direction and suppressing the intensity in other directions, the direction of the electromagnetic beam is changed, for example, a phase shifter is controlled by a computer to change the phase distribution over the aperture of the antenna, thereby realizing the scanning of the beam in space.
Although phased array scanning radar has many advantages, it also has many disadvantages. Firstly, the equipment of the phased array scanning radar is complex, which causes the cost to be extremely high; and the range of beam scanning has a certain limit, and the beam width of the beam scanning can change along with the scanning direction. The scanning range of a common phased array scanning radar is about 90 degrees, the scanning field of view is relatively small, and the scanning field of view needs to be enlarged and can be realized by matching with a plurality of antenna arrays, so that the use of the phased array scanning radar is limited.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problem, an object of the embodiments of the present invention is to provide a terahertz modulation unit, a terahertz modulator, and a radar transmission system.
In a first aspect, an embodiment of the present invention provides a terahertz modulation unit, including: high electron mobility transistors and super surface structures; the high electron mobility transistor comprises a body, and a source electrode, a drain electrode and a grid electrode which are arranged on the same side of the body; the high electron mobility transistor is used for forming two-dimensional electron gas with different concentrations between the source electrode and the drain electrode according to different voltages applied by the grid electrode; the super-surface structure comprises a first super-surface structure and a second super-surface structure; the first super-surface structure is arranged on the surface of the source electrode, ohmic contact is formed between the first super-surface structure and the source electrode, the second super-surface structure is arranged on the surface of the drain electrode, and ohmic contact is formed between the second super-surface structure and the drain electrode; the super-surface structure is used for emitting target frequency waves in incident terahertz waves with different frequencies to a target direction according to the two-dimensional electron gas with different concentrations; the target frequency wave is a terahertz wave having a frequency responsive to the concentration of the two-dimensional electron gas, and the target direction is an emission direction corresponding to the target frequency wave.
Optionally, the high electron mobility transistor is a depletion type.
Optionally, the body comprises: a buffer layer and a barrier layer; the barrier layer is arranged on the surface of one side of the buffer layer, and the source electrode, the drain electrode and the grid electrode are arranged on one side, away from the buffer layer, of the barrier layer; the high electron mobility transistor forms the two-dimensional electron gas at a heterojunction between the buffer layer and the barrier layer, and the two-dimensional electron gas moves between the heterojunction.
Optionally, the body further comprises: a substrate layer and a cap layer; the substrate layer is arranged on one side, far away from the barrier layer, of the buffer layer; the cap layer is arranged on one side, far away from the buffer layer, of the barrier layer, and the source electrode, the drain electrode and the grid electrode are arranged on one side, far away from the barrier layer, of the cap layer.
Optionally, the super-surface structure is a metallic super-surface structure.
Optionally, the material of the super-surface structure is gold.
Optionally, the terahertz modulation unit further includes: an insulating medium; the insulation medium is filled around the super-surface structure.
Optionally, the material of the insulating medium is benzocyclobutene.
In a second aspect, the embodiment of the present invention provides a terahertz modulator, including: the terahertz modulation units are arranged in an array manner.
Alternatively, different voltages are respectively applied to a plurality of terahertz modulation units located in different rows or columns.
In a third aspect, an embodiment of the present invention provides a radar transmission system, including: the terahertz modulator and the terahertz wave source as described in any one of the above; the terahertz wave source is used for transmitting terahertz waves with different frequencies to the terahertz modulator.
The embodiment of the utility model provides an in the above-mentioned scheme that first aspect provided, combine together high electron mobility transistor and super surface structure, utilize terahertz wave of different frequencies can produce the characteristics of resonance effect with the two-dimensional electron gas of the different concentrations that produce in the high electron mobility transistor, exert different voltages through adjusting the grid, adjust the concentration of two-dimensional electron gas, change the electric current size between source and the drain electrode, thereby control the terahertz wave frequency (target frequency wave) that super surface structure can modulate, with the outgoing position that this target frequency wave directive corresponds to it. The terahertz modulation unit can modulate light in a very wide terahertz wave range, and realizes strong modulation effect on light waves under terahertz frequency, so that a radar scanning visual angle adopting the terahertz modulation unit is enlarged; in addition, the terahertz modulation unit also has the advantages of simple structure, low cost, small volume, light weight and the like.
In the embodiment of the present invention, in the solution provided by the second aspect, the terahertz modulator can enlarge the receiving area of the terahertz modulating unit for the terahertz waves; in the modulation process, more target frequency waves can be emitted by the terahertz modulator, the modulation range is large, and the modulation speed is high.
In the embodiment of the present invention, the terahertz modulator can be used to enlarge the scanning field angle of the radar emission system, and the modulation speed is fast and the modulation range is wide; in addition, the radar transmission system has a super-surface structure, and thus the whole radar transmission system is lighter.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the description below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 shows a schematic diagram of a terahertz modulation unit provided by an embodiment of the present invention;
fig. 2 shows a top view of a terahertz modulation unit provided by an embodiment of the present invention;
fig. 3 shows a schematic diagram of a terahertz modulation unit provided by an embodiment of the present invention, including a buffer layer and a barrier layer;
fig. 4 shows a schematic diagram of a terahertz modulation unit provided by an embodiment of the present invention, including a substrate layer and a cap layer;
fig. 5 shows a schematic diagram of a terahertz modulator provided by an embodiment of the present invention;
fig. 6 shows a schematic diagram of an operating principle of a terahertz modulator provided by an embodiment of the present invention;
fig. 7 shows a schematic structural diagram of a radar transmission system provided by an embodiment of the present invention;
fig. 8 shows a top view of embodiment 1 provided by an embodiment of the present invention;
fig. 9 is a schematic diagram showing transmittance for terahertz waves of different frequencies in example 1 provided in an embodiment of the present invention;
fig. 10 is a schematic diagram showing a modulation result of phase angles of terahertz waves of different frequencies in embodiment 1 provided by the present invention.
Icon:
the terahertz wave source comprises a 1-high electron mobility transistor, a 2-super surface structure, a 3-insulating medium, a 10-body, a 11-source electrode, a 12-drain electrode, a 13-grid electrode, a 21-first super surface structure, a 22-second super surface structure, a 101-buffer layer, a 102-barrier layer, a 103-substrate layer, a 104-cap layer, a 100-terahertz modulation unit, a 200-terahertz modulator and a 300-terahertz wave source.
Detailed Description
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.
In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
The embodiment of the utility model provides a terahertz modulation unit is provided, it is shown with reference to fig. 1, this terahertz modulation unit includes: a high electron mobility transistor 1 and a super-surface structure 2; the high electron mobility transistor 1 comprises a body 10, and a source electrode 11, a drain electrode 12 and a gate electrode 13 which are arranged on the same side of the body 10; wherein a specific reference numeral "1" of the high electron mobility transistor 1 is not directly shown in fig. 1, and fig. 1 shows a body 10, a source 11, a drain 12, and a gate 13 to represent the high electron mobility transistor 1; the hemt 1 is configured to form two-dimensional electron gas (2deg, two-dimensional electron gas) with different concentrations between the source electrode 11 and the drain electrode 12 according to different voltages applied to the gate electrode 13; the channel formed by the double dotted line in fig. 1 indicates the position where the two-dimensional electron gas is located.
As shown in fig. 1, the super-surface structure 2 includes a first super-surface structure 21 and a second super-surface structure 22; wherein the particular reference numeral "2" of the super-surface structure 2 is likewise not directly shown in fig. 1, fig. 1 shows a first super-surface structure 21 and a second super-surface structure 22 to represent the super-surface structure 2. The first super-surface structure 21 is arranged on the surface of the source electrode 11, ohmic contact is formed between the first super-surface structure and the source electrode, and the second super-surface structure 22 is arranged on the surface of the drain electrode 12, and ohmic contact is formed between the first super-surface structure and the drain electrode; the super-surface structure 2 is used for emitting a target frequency wave in incident terahertz waves with different frequencies to a target direction according to two-dimensional electron gas with different concentrations; the target frequency wave is a terahertz wave having a frequency responsive to the concentration of the two-dimensional electron gas, and the target direction is an emission direction corresponding to the target frequency wave.
In the embodiment of the present invention, the High Electron Mobility Transistor 1 may also be referred to as a HEMT (High Electron Mobility Transistor), which is a semiconductor material having High Electron Mobility, saturated Electron velocity, and breakdown voltage. As shown in fig. 1, a source 11, a drain 12 and a gate 13 are respectively disposed on one side surface of a body 10 (e.g., an upper surface of the body 10 in fig. 1) of the hemt 1, and the source 11, the drain 12 and the gate 13 have a certain gap therebetween, i.e., they are not in contact with each other and are disposed in parallel on the same side surface of the body 10. Wherein, the source electrode 11 and the drain electrode 12 may be two electrodes obtained by high concentration doping, and the gate electrode 13 may be an electrode of schottky contact; in addition, the body 10 of the hemt 1 has a two-dimensional electron gas therein, which moves laterally in the body 10 (e.g., from the right side of the body 10 to the left side thereof in fig. 1), and which constitutes a conductive channel of the hemt 1.
In the embodiment of the present invention, the high electron mobility transistor 1 is a voltage control device, and the voltage inside the high electron mobility transistor 1 can be changed by applying a voltage to the gate 13; among them, different types of high electron mobility transistors 1 (such as depletion type or enhancement type) can affect the two-dimensional electron gas concentration inside the high electron mobility transistor 1 according to the voltage applied to the gate 13, thereby causing the high electron mobility transistor 1 to have different operation states (such as on or off). Alternatively, the high electron mobility transistor 1 is a depletion type. The operation mode of the depletion-type high electron mobility transistor 1 belongs to a normally-on mode, that is, under the condition that no voltage is applied to the gate 13, the two-dimensional electron gas with sufficient concentration is inside the body 10, and the source 11 and the drain 12 can respectively form ohmic contact with the two-dimensional electron gas forming a conductive channel in the body 10, that is, the source 11 and the drain 12 are connected and conducted through the two-dimensional electron gas, a transverse electric field is formed between the source 11 and the drain 12, and the two-dimensional electron gas can move transversely in the transverse electric field, so that a current can be formed between the source 11 and the drain 12; when a voltage (negative voltage) is applied to the gate 13, an electric field opposite to the original lateral electric field is generated inside the body 10, and the concentration of the two-dimensional electron gas inside the body 10 is gradually reduced according to the applied voltage, so that the source 11 and the drain 12 are turned off from being on.
Wherein, in the case where voltages (e.g., negative voltages) of different magnitudes are applied to the gate electrode 13, the two-dimensional electron gas concentration inside the hemt 1 is controlled by the voltages, e.g., gradually decreased; that is to say, the embodiment of the present invention can change the concentration of the two-dimensional electron gas in the body 10 by applying different voltages to the gate 13, that is, generate two-dimensional electron gases with different concentrations.
In the embodiment of the present invention, the super-surface structure 2 is disposed on a side surface of the high electron mobility transistor 1, and the side is a side (above the body 10 in fig. 1) of the high electron mobility transistor 1 having the source 11, the drain 12 and the gate 13. Optionally, the super-surface structure 2 is a metal super-surface structure. The embodiment of the utility model adopts the metal super surface structure, and can utilize the surface plasmon existing in the metal medium to make the super surface structure 2 generate resonance effect (namely surface plasmon resonance) more easily; for example, the metal super-surface structure may be a metal super-surface structure composed of gold, a metal super-surface structure composed of silver, a metal super-surface structure composed of copper, a metal super-surface structure composed of aluminum, or the like. Optionally, the material of the super-surface structure 2 is gold (Au).
Among them, as can be seen from fig. 2, fig. 2 shows a top view of the terahertz modulation unit, and fig. 2 only shows the super-surface structure 2 and the body 10; the first super-surface structure 21 and the second super-surface structure 22 included in the super-surface structure 2 may be completely the same two-part structure, for example, the first super-surface structure 21 and the second super-surface structure 22 may be made of the same material and thickness; the first super-surface structure 21 is disposed in contact with the source 11, as shown in fig. 1, the first super-surface structure 21 is disposed on a side of the source 11 away from the body 10, and similarly, the second super-surface structure 22 is disposed in contact with the drain 12, as shown in fig. 1, the second super-surface structure 22 is also disposed on a side of the drain 12 away from the body 10. The embodiment of the utility model provides a through setting up super surface structure 2 like this, can make first super surface structure 21 and source 11 form ohmic contact respectively, make the super surface structure 22 of second and drain 12 form ohmic contact, promptly, make first super surface structure 21 and source 11 switch on respectively, make the super surface structure 22 of second and drain 12 switch on.
When the concentration of the two-dimensional electron gas moving laterally between the source electrode 11 and the drain electrode 12 is changed by the voltage applied to the gate electrode 13, the current generated between the source electrode 11 and the drain electrode 12 changes accordingly, for example, the current in the conductive channel formed by the two-dimensional electron gas changes, so that the terahertz wave incident therein is modulated correspondingly by the first super-surface structure 21 covering the surface of the source electrode 11 and the second super-surface structure 22 covering the surface of the drain electrode 12. The terahertz waves emitted into the super-surface structure 2 are broadband electromagnetic waves, the terahertz waves comprise various different frequencies, and the terahertz waves with different frequencies can respond to two-dimensional electron gas with different concentrations. Specifically, when the two-dimensional electron gas with a certain concentration is generated in the body 10 due to the voltage applied by the gate 13, the two-dimensional electron gas with the certain concentration can form a certain amount of current between the source 11 and the drain 12, and generate a resonance effect on a target frequency wave corresponding to a certain frequency in the terahertz waves incident into the super-surface structure 2, and the terahertz waves with the frequency can generate the resonance effect under the action of the two-dimensional electron gas with the certain concentration, so that the super-surface structure 2 can modulate the target frequency wave, and modulate the target frequency wave to emit the target frequency wave to a target direction; the embodiment of the utility model provides an in, terahertz wave of different frequencies can directive different target directions respectively after surpassing surface structure 2's modulation, and terahertz wave frequency is the relation of one-to-one rather than the outgoing direction promptly.
The embodiment of the utility model provides a combine together high electron mobility transistor 1 and super surface structure 2, utilize terahertz wave of different frequencies can produce resonance effect's characteristics with the two-dimensional electron gas of the different concentrations that produce in high electron mobility transistor 1, exert different voltages through adjusting grid 13, adjust the concentration of two-dimensional electron gas, change the electric current size between source 11 and drain electrode 12, thereby control the terahertz wave frequency (target frequency wave) that super surface structure 2 can modulate, with the outgoing position that this target frequency wave directive corresponds to it. The terahertz modulation unit can modulate light in a very wide terahertz wave range, and realizes strong modulation effect on light waves under terahertz frequency, so that a radar scanning visual angle adopting the terahertz modulation unit is enlarged; in addition, the terahertz modulation unit also has the advantages of simple structure, low cost, small volume, light weight and the like.
Alternatively, as shown in fig. 3, the body 10 includes: a buffer layer 101 and a barrier layer 102; a barrier layer 102 is arranged on the surface of one side of the buffer layer 101, and a source electrode 11, a drain electrode 12 and a grid electrode 13 are arranged on one side of the barrier layer 102 away from the buffer layer 101; the high electron mobility transistor 1 forms a two-dimensional electron gas at the heterojunction between the buffer layer 101 and the barrier layer 102, and the two-dimensional electron gas moves between the heterojunctions.
As shown in fig. 3, the source 11, the drain 12 and the gate 13 of the hemt 1 are disposed on the surface of the body 10 on one side of the barrier layer 102, and the buffer layer 101 of the body 10 is disposed in contact with the other side of the barrier layer 102 (e.g., the side of the barrier layer 102 away from the source 11, the drain 12 and the gate 13); as shown in fig. 3, the buffer layer 101 is located at a lower portion of the body 10, the barrier layer 102 is located at an upper surface of the buffer layer 101 (e.g., an upper portion of the body 10), and the other side surface of the barrier layer 102 (e.g., a side surface away from the buffer layer 101, an upper surface of the barrier layer 102 in fig. 3) is provided with the source electrode 11, the drain electrode 12, and the gate electrode 13.
The buffer layer 101 and the barrier layer 102 are two semiconductor material layers with different forbidden band widths and different fermi levels, for example, the material of the buffer layer 101 may be undoped GaAs (gallium arsenide), and the material of the barrier layer 102 may be AlGaAs (aluminum gallium arsenide); a heterojunction is generated between the buffer layer 101 and the barrier layer 102, and due to the difference in forbidden bandwidth between two semiconductor materials (such as the material of the buffer layer 101 and the material of the barrier layer 102) on both sides of the heterojunction, free electrons flow from the wide-bandgap semiconductor to the narrow-bandgap semiconductor, so that a quantum well is formed on the narrow-bandgap side of the semiconductor interface, for example, when the forbidden bandwidth of the buffer layer 101 is large and the forbidden bandwidth of the barrier layer 102 is small, free electrons can flow from the buffer layer 101 to the barrier layer 102, and a quantum well is formed on one side (between the heterojunctions) of the barrier layer 102 close to the buffer layer 101, where the quantum well is a preliminarily formed two-dimensional electron gas; when the difference in conduction band between the heterojunctions (the difference in forbidden band widths of the semiconductor materials on both sides) is large, a high potential barrier is generated, and the movement of free electrons of a two-dimensional electron gas (quantum well) in a direction perpendicular to the heterojunction (such as the vertical direction in fig. 3) is limited, so that the two-dimensional electron gas can move laterally inside the heterojunction.
Optionally, referring to fig. 4, the body 10 further includes: a substrate layer 103 and a cap layer 104; the substrate layer 103 is arranged on one side of the buffer layer 101 far away from the barrier layer 102; the cap layer 104 is disposed on a side of the barrier layer 102 away from the buffer layer 101, and a side of the cap layer 104 away from the barrier layer 102 is provided with the source electrode 11, the drain electrode 12, and the gate electrode 13.
In the embodiment of the present invention, a substrate layer 103 may be disposed at the bottom layer of the high electron mobility transistor 1, and a cap layer 104 may be disposed between the barrier layer 102 and the source electrode 11, the drain electrode 12, and the gate electrode 13; for example, as shown in fig. 4, a buffer layer 101, a barrier layer 102, and a cap layer 104 are provided in this order on the upper surface of a substrate layer 103, and a source electrode 11, a drain electrode 12, and a gate electrode 13 are provided in parallel on the upper surface of the cap layer 104. The substrate layer 103 may be made of SiC (silicon carbide), si (silicon), sapphire, or the like; the material of the cap layer 104 may be GaAs (gallium arsenide) to reduce oxidation of the barrier layer 102 for oxidation protection.
Optionally, referring to fig. 4, the terahertz modulation unit further includes: an insulating medium 3; the insulation medium 3 is filled around the super-surface structure 2, and the height of the insulation medium can be lower than that of the super-surface structure 2; as shown in fig. 4, an insulating dielectric 3 may separate the source 11 from the drain 12. Alternatively, the material of the insulating medium 3 is benzocyclobutene, which is a novel active resin and has excellent electrical insulating properties.
The embodiment of the utility model provides a terahertz modulator is still provided, it is shown with reference to fig. 5, this terahertz modulator includes: a plurality of terahertz modulation units 100 as described above, and the plurality of terahertz modulation units 100 are arranged in an array. The plurality of terahertz modulation units 100 can be arranged in an array form, and the terahertz modulator formed by the terahertz modulation units can enlarge the receiving area of the terahertz modulation units 100 for terahertz waves; in the modulation process, the terahertz modulator is large in modulation range and high in modulation speed.
Alternatively, referring to fig. 6, the terahertz modulator may apply different voltages to a plurality of terahertz modulation units 100 located in different rows or columns, respectively.
The embodiment of the utility model provides an in, can exert different voltages respectively to the terahertz modulation unit 100 of each line or each row, as shown in fig. 6, exert the voltage of V1-V8 eight kinds of equidimensions respectively to each line of this terahertz modulator (if exert different voltages to the grid 13 of the terahertz modulation unit 100 of each line respectively), make each line of this terahertz modulator can be under the voltage that this line was applyed, form the two-dimensional electron gas of certain concentration, make the two-dimensional electron gas of this concentration can produce resonance effect with the target frequency wave in the terahertz wave received on the super surface structure 2, make each line of terahertz modulation unit 100 can be to certain target frequency wave of corresponding target direction outgoing, in order to realize the modulation respectively of the terahertz wave of different frequencies, obtain the terahertz modulator that can carry out independent control to a plurality of target directions respectively.
The embodiment of the utility model provides a radar transmitting system is still provided, it is shown with reference to fig. 7, this radar transmitting system includes: the terahertz modulator 200 and the terahertz wave source 300 as any one of the above; the terahertz-wave source 300 is used to emit terahertz waves having different frequencies to the terahertz modulator 200. Note that, an enlarged schematic diagram of the terahertz modulator 200 is shown in a dashed line frame in fig. 7.
In the embodiment of the present invention, the terahertz wave source 300 can be disposed on any side of the terahertz modulator 200, for example, as shown in fig. 7, the terahertz wave source 300 can be disposed on one side of the terahertz modulator 200 away from the super-surface structure 2, i.e., on one side closer to the body 10 (e.g., on the left side of the terahertz modulator 200 in fig. 7), and emit terahertz waves with different frequencies to the terahertz modulator 200, and the terahertz waves with different frequencies can penetrate through the hemt 1 of each terahertz modulation unit 100 of the terahertz modulator 200 and enter the super-surface structure 2; alternatively, the terahertz wave source 300 may be disposed on a side of the terahertz modulator 200 close to the super-surface structure 2, that is, a side of the terahertz modulator 200 on which the super-surface structure 2 is disposed, for emitting terahertz waves with different frequencies to the terahertz modulator 200, where the terahertz waves with different frequencies may be directly emitted into the super-surface structure 2 of each terahertz modulation unit 100 in the terahertz modulator 200.
The embodiment of the utility model provides a radar transmitting system, through adopting this terahertz modulator 200, can enlarge this radar transmitting system's scanning angle of vision, and modulation speed is fast, and the scope of modulation is big; further, since the radar transmission system has the super-surface structure 2, the entire system can be made lightweight.
Example 1:
in this embodiment 1, as shown in fig. 4, a terahertz modulation unit 100 is provided, in which a high electron mobility transistor 1 includes a substrate layer 103, a buffer layer 101, a barrier layer 102, a cap layer 104, a source electrode 11, a drain electrode 12, and a gate electrode 13, and a super-surface structure 2 is provided on a side of the high electron mobility transistor 1 away from the substrate layer 103. Wherein, the substrate layer 103 is a Si-based GaAs (silicon-based gallium arsenide) material; the buffer layer 101 is made of undoped GaAs material, and the thickness of the buffer layer is 8-10 mu m; barrier layer 102 is an AlGaAs material; the cap layer 104 is a GaAs material; the source electrode 11 and the drain electrode 12 are high-concentration doped electrodes, and the thickness of the two electrodes is 2.5 μm; the gate 13 is an electrode of schottky contact; the insulating medium 3 is a benzocyclobutene material; the material of the super-surface structure 2 is metal gold (Au).
Specifically, the detailed dimensional parameters of the terahertz modulation unit 100 are shown in fig. 8, and are not described herein again. Referring to fig. 9, fig. 9 is a schematic diagram showing the transmittance of the terahertz modulation unit 100 for terahertz waves of different frequencies; as can be seen from fig. 9, the transmittance curve corresponding to 0V represents at each point on the curve: the percentage of the transmission rate of the super-surface structure 2 for terahertz waves of a certain frequency; similarly, the curve corresponding to 8V is the same meaning, and is not described herein again; in addition to the 0V curve and the 8V curve, another curve is present in fig. 9, which shows the change of transmittance with frequency at a certain voltage between 0V and 8V; it can be seen that, under the action of different voltages, the terahertz modulation unit 100 provided in this embodiment 1 has different transmittances for terahertz waves of different frequencies.
Referring to fig. 10, fig. 10 is a schematic diagram showing the modulation result of the terahertz modulation unit 100 for the phase angles of terahertz waves of different frequencies; as can be seen from fig. 10, in the case where the frequency of the terahertz wave is 2.8THz, the phase angle is 0.85rad when a voltage of 0V is applied to the gate 13, and the phase angle is-0.25 rad when a voltage of 8V is applied to the gate 13; that is, in the process of changing from 0V to 8V, the phase angle is changed by 65.9%, which indicates that the phase angle of the target frequency wave can be changed by adjusting the voltage, and the purpose of modulation can be achieved.
The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the technical solutions of the changes or replacements within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (11)
1. A terahertz modulation unit is characterized by comprising: a high electron mobility transistor (1) and a super-surface structure (2);
the high electron mobility transistor (1) comprises a body (10) and a source electrode (11), a drain electrode (12) and a grid electrode (13) which are arranged on the same side of the body (10); the high electron mobility transistor (1) is used for forming two-dimensional electron gas with different concentrations between the source electrode (11) and the drain electrode (12) according to different voltages applied by the grid electrode (13);
the super-surface structure (2) comprises a first super-surface structure (21) and a second super-surface structure (22); the first super surface structure (21) is arranged on the surface of the source electrode (11) and forms ohmic contact with the source electrode, and the second super surface structure (22) is arranged on the surface of the drain electrode (12) and forms ohmic contact with the drain electrode;
the super-surface structure (2) is used for emitting a target frequency wave in incident terahertz waves with different frequencies to a target direction according to the two-dimensional electron gas with different concentrations; the target frequency wave is a terahertz wave having a frequency responsive to the concentration of the two-dimensional electron gas, and the target direction is an emission direction corresponding to the target frequency wave.
2. The terahertz modulation unit according to claim 1, wherein the high electron mobility transistor (1) is depletion-type.
3. The terahertz modulation unit according to claim 1, wherein the body (10) comprises: a buffer layer (101) and a barrier layer (102);
the barrier layer (102) is arranged on the surface of one side of the buffer layer (101), and the source electrode (11), the drain electrode (12) and the gate electrode (13) are arranged on one side, away from the buffer layer (101), of the barrier layer (102);
the high electron mobility transistor (1) forms the two-dimensional electron gas at a heterojunction between the buffer layer (101) and the barrier layer (102), and the two-dimensional electron gas moves between the heterojunctions.
4. The terahertz modulation unit of claim 3, wherein the body (10) further comprises: a substrate layer (103) and a cap layer (104);
the substrate layer (103) is arranged on one side of the buffer layer (101) far away from the barrier layer (102); the cap layer (104) is arranged on the side of the barrier layer (102) far away from the buffer layer (101), and the source electrode (11), the drain electrode (12) and the grid electrode (13) are arranged on the side of the cap layer (104) far away from the barrier layer (102).
5. The terahertz modulation unit according to claim 1, wherein the super-surface structure (2) is a metal super-surface structure.
6. The terahertz modulation unit according to claim 5, wherein the material of the super-surface structure (2) is gold.
7. The terahertz modulation unit of claim 1, further comprising: an insulating medium (3); the insulation medium (3) is filled around the super-surface structure (2).
8. The terahertz modulation unit according to claim 7, wherein the insulating medium (3) is benzocyclobutene.
9. A terahertz modulator, comprising: a plurality of terahertz modulating units (100) as claimed in any one of claims 1 to 8, wherein the plurality of terahertz modulating units (100) are arranged in an array.
10. The terahertz modulator according to claim 9, wherein different voltages are applied to the plurality of terahertz modulation units (100) located in different rows or columns, respectively.
11. A radar transmission system, comprising: the terahertz modulator (200) and the terahertz wave source (300) as claimed in any one of claims 9 to 10 above;
the terahertz wave source (300) is used for emitting terahertz waves with different frequencies to the terahertz modulator (200).
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11927769B2 (en) | 2022-03-31 | 2024-03-12 | Metalenz, Inc. | Polarization sorting metasurface microlens array device |
| US11978752B2 (en) | 2019-07-26 | 2024-05-07 | Metalenz, Inc. | Aperture-metasurface and hybrid refractive-metasurface imaging systems |
| US11988844B2 (en) | 2017-08-31 | 2024-05-21 | Metalenz, Inc. | Transmissive metasurface lens integration |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11988844B2 (en) | 2017-08-31 | 2024-05-21 | Metalenz, Inc. | Transmissive metasurface lens integration |
| US11978752B2 (en) | 2019-07-26 | 2024-05-07 | Metalenz, Inc. | Aperture-metasurface and hybrid refractive-metasurface imaging systems |
| US11927769B2 (en) | 2022-03-31 | 2024-03-12 | Metalenz, Inc. | Polarization sorting metasurface microlens array device |
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