Photoconductive antenna assembly for generating THz radiation
By introducing multiple metal antenna oscillators and metamaterial layers into photoconductive antennas (PCA), the electromagnetic field strength between antenna oscillators is improved, and the problem of low conversion efficiency of existing PCA in the high frequency band is solved, achieving more efficient THz radiation output.
Patent Information
- Application Number
- CN202280101842.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-15
- Publication Date
- 2025-06-20
AI Technical Summary
Existing photoconductive antennas (PCAs) have low optical-THz conversion efficiency in the 100GHz to 500GHz frequency band, limiting their application.
By introducing a dielectric semiconductor substrate and a plurality of metal antenna oscillators into the PCA assembly and defining a focus portion between the antenna oscillators, the electromagnetic field strength is increased using ε-negative (ENG) and ε-near-zero (ENZ) metamaterial layers to increase the electromagnetic field strength and increase the output power of THz radiation.
The optical-THz conversion efficiency of the photoconductive antenna is significantly improved, the output power of the antenna is enhanced, the electrical size is reduced, and the integration is improved.
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Figure CN120188009A_ABST
Abstract
Description
Technical Field
[0001] The present invention generally relates to antenna technology. More specifically, the present invention relates to a photoconductive antenna (PCA) assembly for generating THz radiation (e.g., for wireless communication) and a method of operating such a PCA assembly. Background Art
[0002] Terahertz (THz) waves have several unique capabilities and characteristics, including those that enable their use in wireless communication, chemical identification, material characterization, biosensing, and medical imaging, among others. One of the most common methods for generating THz waves is to use a photoconductive antenna (PCA), in which an ultrafast femtosecond laser interacts with a biased photoconductive semiconductor having a sub-picosecond carrier lifetime (usually low-temperature-grown GaAs (LT-GaAs)), thereby generating a transient photocurrent. According to radiation theory, a transient photocurrent with a pulse width of sub-picoseconds generates electromagnetic wave radiation in the THz frequency spectrum. However, despite the many advantages of the PCA, such as room-temperature operation, compact design, and broadband radiation, the optical-THz conversion efficiency of the PCA is low, especially in the 100 GHz to 500 GHz frequency band, which limits the application of the PCA.
[0003] The optical-THz conversion efficiency of the PCA is essentially based on quantum effects. Several methods have been proposed to improve the efficiency of the PCA by increasing the field strength at the PCA feed point (e.g., by using a high-impedance surface, shaping the antenna oscillator, or using a plasmonic structure). However, these conventional methods still have one or more of the following disadvantages: low efficiency and high loss, impedance matching problems, large electrical size, high-cost manufacturing processes, and / or integration problems (especially at higher frequencies). Summary of the Invention
[0004] An object of the present invention is to provide an improved photoconductive antenna (PCA) assembly for generating THz radiation, e.g., for wireless communication, and a method of operating such a PCA assembly.
[0005] The above and other objects are achieved by the subject matter of the independent claims. Other implementations are apparent from the dependent claims, the description, and the drawings.
[0006] According to a first aspect, a photoconductive antenna (PCA) assembly for generating THz radiation is provided. The PCA assembly includes a dielectric semiconductor substrate and a plurality of metal antenna oscillators (also referred to as metal contacts), the plurality of metal antenna oscillators including a first antenna oscillator and at least a second antenna oscillator defining an antenna unit of the PCA assembly. The first antenna oscillator and the second antenna oscillator are disposed on the dielectric semiconductor substrate to define a focusing portion (also referred to as a feed gap) between the first antenna oscillator and the second antenna oscillator. Further, the PCA assembly includes a femtosecond laser for emitting laser radiation onto the focusing portion to generate the THz radiation. The focusing portion between the first antenna oscillator and the second antenna oscillator includes a plurality of material layers disposed on the semiconductor substrate between the first antenna oscillator and the second antenna oscillator, the plurality of material layers including a first epsilon-negative (ENG) metamaterial layer adjacent to the first antenna oscillator, an intermediate epsilon-near-zero (ENZ) metamaterial layer, and a second ENG metamaterial layer adjacent to the second antenna oscillator. Thus, the photoconductive antenna (PCA) assembly for generating THz radiation has a higher optical-THz conversion efficiency. The PCA assembly according to the first aspect achieves geometric confinement of electromagnetic waves by enhancing the electromagnetic field intensity at the antenna feeder with metamaterials, thereby improving the antenna efficiency.
[0007] It should be understood that the working principle of the PCA assembly according to the first aspect for generating THz radiation is generally based on the ultrafast change effect of the surface photoconductivity of the semiconductor substrate under the laser irradiation generated by the femtosecond laser. Due to the excitation of the materials in the focusing portion between the first antenna oscillator and the second antenna oscillator by the femtosecond laser, the charge carrier concentration in this region increases sharply within a short time, and THz pulses are generated. Since the duration of a single short THz pulse generated is typically about several hundred femtoseconds, the pulse spectrum generally extends over several octaves in the THz frequency range.
[0008] Loading the PCA assembly according to the first aspect with metamaterials significantly enhances the electric field intensity at the focusing portion (i.e., the antenna feed port), thus contributing to improving the output power of the PCA assembly according to the first aspect. Further, due to the plasmonic behavior of the structure, this approach helps to break the refraction limit and reduce the distance between the antenna oscillators. The compact electrical size helps to increase the number of electrons / holes collected by the antenna oscillators and improve the optical-THz conversion efficiency.
[0009] In another possible implementation, the intermediate ENZ metamaterial layer includes a double-positive (DPS) metamaterial layer. This can further improve the optical-THz conversion efficiency.
[0010] In another possible implementation, in the direction extending from the first antenna element through the focusing portion to the second antenna element, the thickness of the intermediate ENZ metamaterial layer is less than the sum of the thicknesses of the first ENG metamaterial layer and the second ENG metamaterial layer. This can further improve the optical-THz conversion efficiency.
[0011] In another possible implementation, the intermediate ENZ metamaterial layer of the PCA component extends from the semiconductor substrate to a first height, and the first ENG metamaterial layer and / or the second ENG metamaterial layer extend to a second height greater than the first height. This enables further improvement of the optical-THz conversion efficiency and requires less intermediate ENZ metamaterial.
[0012] In another possible implementation, the focusing portion further includes an intermediate ENG metamaterial layer disposed on top of the intermediate ENZ metamaterial layer and between the first ENG metamaterial layer and the second ENG metamaterial layer. This can further improve the optical-THz conversion efficiency.
[0013] In another possible implementation, the first ENG metamaterial layer and the second ENG metamaterial layer include the same ENG metamaterial. This enables the PCA component to be manufactured in an efficient manner.
[0014] In another possible implementation, the first ENG metamaterial layer and the second ENG metamaterial layer are substantially planar layers. This enables the PCA component to be manufactured in an efficient manner.
[0015] In another possible implementation, the intermediate ENZ metamaterial layer further includes a graphene layer or an optically conductive material layer arranged in contact with the first ENG metamaterial layer. This can further improve the optical-THz conversion efficiency.
[0016] In another possible implementation, the intermediate ENZ metamaterial layer further includes a gold layer or a metal layer arranged in contact with the third ENG metamaterial layer. This can further improve the optical-THz conversion efficiency.
[0017] In another possible implementation, the first antenna element and / or the second antenna element are made of gold and / or graphene. This enables the electron mobility of the first antenna element and / or the second antenna element to be improved, thereby improving the transmission efficiency of the PCA component.
[0018] In another possible implementation, the PCA component further includes a graphene layer or an optically conductive material layer disposed between the first antenna oscillator and the semiconductor substrate and / or a graphene layer or an optically conductive material layer disposed between the second antenna oscillator and the semiconductor substrate. This can further improve the optical-THz conversion efficiency.
[0019] In another possible implementation, the first antenna oscillator and the second antenna oscillator define an antenna unit of the PCA component, wherein other antenna oscillators among the plurality of antenna oscillators define one or more other antenna units of the PCA component, wherein the one or more other antenna units have the same configuration as the antenna unit defined by the first antenna oscillator and the second antenna oscillator, and wherein at least one of the one or more other antenna units has a different size from the antenna unit defined by the first antenna oscillator and the second antenna oscillator. Arranging a plurality of antenna units on a dielectric semiconductor substrate enables an increase in the bandwidth of the generated THz radiation.
[0020] According to a second aspect, a method for generating THz radiation using a photoconductive antenna (PCA) component is provided. The method includes the step of emitting laser radiation from a femtosecond laser onto a focusing portion of the PCA component, wherein the focusing portion of the PCA component is defined between a first antenna oscillator and a second antenna oscillator disposed on a dielectric semiconductor substrate. The focusing portion between the first antenna oscillator and the second antenna oscillator includes a plurality of material layers disposed on the dielectric semiconductor substrate between the first antenna oscillator and the second antenna oscillator, and the plurality of material layers includes a first epsilon-negative (ENG) metamaterial layer adjacent to the first antenna oscillator, an intermediate epsilon-near-zero (ENZ) metamaterial layer, and a second ENG metamaterial layer adjacent to the second antenna oscillator.
[0021] The method provided by the second aspect of the present invention can be executed by the AP provided by the first aspect of the present invention. Therefore, other features of the method provided by the second aspect of the present invention are directly implemented by the functions of the AP provided by the first aspect of the present invention and its above-described and below-described different implementations.
[0022] One or more embodiments will be described in detail in the accompanying drawings and the following description. Other features, objectives, and advantages are apparent in the specification, the drawings, and the claims. Description of the Drawings
[0023] Figure 1Shows a schematic perspective view of a PCA component for generating THz radiation according to an embodiment;
[0024] Figure 2a and Figure 2b Shows Figure 1 a schematic cross-sectional side view and a top view of the PCA component of
[0025] Figure 3a and Figure 3b shows a perspective view and a schematic cross-sectional side view of the focusing part of the PCA component according to an embodiment;
[0026] Figure 4a and Figure 4b shows a perspective view and a schematic cross-sectional side view of the focusing part of the PCA component according to another embodiment;
[0027] Figure 5 Shows a schematic perspective view of a PCA component for generating THz radiation according to another embodiment;
[0028] Figure 6a and Figure 6b shows Figure 5 a perspective view and a schematic cross-sectional side view of the focusing part of the PCA component of
[0029] Figure 7 Shows a schematic perspective view of a PCA component for generating THz radiation according to another embodiment;
[0030] Figure 8 Shows a flowchart of the steps of a method for generating THz radiation according to an embodiment;
[0031] Hereinafter, the same reference numerals refer to the same or at least functionally equivalent features. Detailed Description
[0032] In the following description, reference is made to the accompanying drawings that form a part of the present invention, which illustrate specific aspects of embodiments of the present invention or specific aspects in which embodiments of the present invention can be used. It should be understood that the embodiments of the present invention can be used in other aspects and can include structural or logical changes not described in the drawings. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
[0033] For example, it should be understood that the disclosure related to the described method is also applicable to the corresponding device or system for performing the method, and vice versa. For example, if one or more specific method steps are described, the corresponding device may include one or more units (e.g., functional units) to perform the one or more described method steps (e.g., one unit performs one or more steps, or multiple units respectively perform one or more of the multiple steps), even if such one or more units are not explicitly described or illustrated in the drawings. On the other hand, for example, if a specific device is described based on one or more units (e.g., functional units), the corresponding method may include a step to perform the functions of the one or more units (e.g., one step performs the functions of one or more units, or multiple steps respectively perform the functions of one or more of the multiple units), even if such one or more steps are not explicitly described or shown in the drawings. In addition, it should be understood that unless otherwise explicitly stated, the features of the various exemplary embodiments and / or aspects described herein may be combined with each other.
[0034] Figure 1 Fig. 4 shows a schematic perspective view of a PCA component 100 for generating THz radiation according to one embodiment. Figure 2a and Figure 2b shows Figure 1 a schematic cross-sectional side view and a top view of the PCA component 100. The PCA component 100 includes a dielectric semiconductor substrate 110 (as Figure 2a shown, the dielectric semiconductor substrate 110 may have a height h sub ), and a first bowtie antenna oscillator 120a and a second bowtie antenna oscillator 120b that define the bowtie antenna unit of the PCA component 100. Although in the embodiments shown in Figure 1 , Figure 2a , Figure 2b , the first antenna oscillator 120a and the second antenna oscillator 120b are implemented as bowtie antenna oscillators 120a, 120b, in other embodiments, the first antenna oscillator 120a and the second antenna oscillator 120b may be based on different antenna structures. In one embodiment, the first antenna oscillator 120a and / or the second antenna oscillator 120b are made of gold and / or graphene.
[0035] The first antenna oscillator 120a and the second antenna oscillator 120b, which may have a height H, are arranged on the dielectric semiconductor substrate 110 to define a first focusing portion 130a and a second focusing portion 130b (also referred to as feed gaps 130a, 130b) having a corresponding width W Gap therebetween. Although in Figure 1 , Figure 2a , Figure 2bIn the illustrated embodiment, the first antenna element 120a and the second antenna element 120b define two focusing portions 130a, 130b, but in other embodiments, the first antenna element 120a and the second antenna element 120b may define one focusing portion or more than two focusing portions. In the following description, the first focusing portion 130a will be described in more detail as a possible implementation of the multiple focusing portions of the PCA component 100. The PCA component 100 also includes a femtosecond laser (not shown in the figure), wherein the femtosecond laser is used to emit laser radiation onto one or more focusing portions 130a, 130b for generating THz radiation.
[0036] Figure 3a and Figure 3b show Figure 1 and Figure 2a 、 Figure 2b a perspective view and a schematic cross-sectional side view of an exemplary focusing portion 130a of the PCA component 100 shown in. The focusing portion 130a between the first antenna element 120a and the second antenna element 120b includes a plurality of material layers disposed on the semiconductor substrate 110 between the first antenna element 120a and the second antenna element 120b. In Figure 3a 、 Figure 3b the illustrated embodiment, the plurality of material layers include a first epsilon-negative (ENG) metamaterial layer 131a adjacent to (especially in contact with) the first antenna element 120a, an intermediate epsilon-near-zero (ENZ) metamaterial layer, and a second ENG metamaterial layer 131b adjacent to (especially in contact with) the second antenna element 120b. According to one embodiment, in the direction extending from the first antenna element 120a through the focusing portion 130a to the second antenna element 120b, the thickness of the intermediate ENZ metamaterial layer is less than the sum of the thicknesses of the first ENG metamaterial layer 131a and the second ENG metamaterial layer 131b.
[0037] In Figure 3a and 3bIn the illustrated embodiment, the intermediate epsilon-near-zero (ENZ) metamaterial layer includes a central double-positive (DPS) metamaterial layer 135 and a graphene layer 132a (or a layer 132a made of an optically conductive material) arranged to contact the first ENG metamaterial layer 131a, and a gold layer 132b (or a different metal layer 132b) arranged to contact the second ENG metamaterial layer 131b. Loading the focusing section 130a with the ENZ metamaterial layer (where ∈r≈0 and μr>0) enables the enhancement of the field intensity in this region. It should be understood that the first ENG metamaterial layer 131a and the second ENG metamaterial layer 131b have physical properties ∈r<0 and μr>0, and the DPS metamaterial layer 135 has physical properties ∈r>0 and μr>0. For further details on the metamaterials implemented by the PCA component 100, please refer to "Optical metamaterials" by Cai W and Shalaev VM. New York: Springer; 2010 and Cui TJ, Smith DR, Liu R, "Metamaterials". Boston, MA, USA, Springer; 2010, the full text of which is cited herein.
[0038] It should be understood that the working principle of the PCA component 100 for generating THz radiation is generally based on the ultrafast change effect of the surface photoconductivity of the semiconductor substrate 110 under the irradiation of a laser generated by a femtosecond laser. Due to the excitation of the material in the focusing section 130a between the first antenna oscillator 120a and the second antenna oscillator 120b by the femtosecond laser, the charge carrier concentration in this region increases sharply within a short time, generating THz pulses. Since the duration of a single short THz pulse generated is typically about several hundred femtoseconds, the pulse spectrum usually extends over several octaves in the THz frequency range. The PCA component 100 disclosed herein realizes the geometric confinement of electromagnetic waves by enhancing the electromagnetic field intensity at the antenna feeder through metamaterials, thereby improving the antenna efficiency.
[0039] Figure 4a and Figure 4b A perspective view and a schematic cross-sectional side view of an exemplary focusing section 130a of the PCA component 100 according to another embodiment are shown. In Figure 4a and Figure 4b In the illustrated embodiment of the PCA component 100, the ENZ metamaterial layer, including the DPS metamaterial layer 135, the graphene layer 132a (or a layer 132a made of an optically conductive material), and the gold layer 132b (or a different metal layer 132b) extends to a lower height than in the previous embodiment. In other words, in Figure 4a and Figure 4bIn the illustrated embodiment, the intermediate ENZ metamaterial layer extends from the semiconductor substrate 110 to a first height h, while the first ENG metamaterial layer 131a and the second ENG metamaterial layer 131b extend to a higher second height H. In Figure 4a and Figure 4b the illustrated embodiment, the focusing portion 130a further includes an intermediate ENG metamaterial layer 131c disposed on top of the intermediate ENZ metamaterial layer and between the first ENG metamaterial layer 131a and the second ENG metamaterial layer 131b. In one embodiment, the first ENG metamaterial layer 131a, the second ENG metamaterial layer 131b, and the intermediate ENG metamaterial layer 131c may be provided by a single ENG metamaterial layer 131a to 131c. According to Figure 4a 、 Figure 4b the illustrated embodiment, when the height of the ENZ metamaterial layer is reduced, the efficiency of electromagnetic field focusing is higher and the performance is more uniform. In addition, the plasma mode can be excited, which further improves the focusing characteristics.
[0040] Figure 5 FIG. shows a schematic perspective view of a PCA component 100 for generating THz radiation according to another embodiment. Figure 6a and Figure 6b show Figure 5 a perspective view and a schematic cross-sectional side view of the focusing portion of the PCA component 100. Figure 5 、 Figure 6a 、 Figure 6b The PCA component 100 shown in Figure 4a 、 Figure 4b is a variant of the previous embodiment of the PCA component 100 (shown in Figure 5 、 Figure 6a 、 Figure 6b ). In the illustrated embodiment in
[0041] Figure 7 FIG., the PCA component 100 further includes a graphene layer 136 (or an optically conductive material layer 136), and the layer 136 is disposed between one side of the first antenna element 120a and / or the second antenna element 120b and the focusing portion 130a and the other side of the semiconductor substrate 110. Figure 7The PCA component 100 of the illustrated embodiment includes a plurality of antenna elements 120a to 120d that define a plurality of antenna units, and these antenna units may have different sizes. For example, antenna elements 120a, 120b define a first central antenna unit, while a plurality of other antenna elements 120c, 120d define four other antenna units arranged around the first central antenna unit. In addition to different sizes, these antenna units can operate in the same manner, that is, having the same configuration as described in the above embodiments. Arranging a plurality of antenna units on the dielectric semiconductor substrate 110 enables an increase in the bandwidth of the generated THz radiation.
[0042] Figure 8 A flowchart of a method 800 for generating THz radiation using a PCA component (especially the above-mentioned PCA component 100) is shown. Method 800 includes a step 801 of emitting laser radiation from a femtosecond laser of the PCA component 100 to a focusing portion 130a of the PCA component 100, where the focusing portion 130a is defined between a first antenna element 120a and a second antenna element 120b of the PCA component 100, and the first antenna element 120a and the second antenna element 120b are arranged on the semiconductor substrate 110 of the PCA component 100. As described above, the focusing portion 130a between the first antenna element 120a and the second antenna element 120b includes a plurality of layers arranged on the semiconductor substrate 110 between the first antenna element 120a and the second antenna element 120b, and these layers include a first epsilon-negative (ENG) metamaterial layer 131a adjacent to the first antenna element 120a, an intermediate epsilon-near-zero (ENZ) metamaterial layer, and a second ENG metamaterial layer 131b adjacent to the second antenna element 120b.
[0043] Those skilled in the art should understand that the "blocks" ("units") in various drawings (methods and devices) represent or describe the functions of the embodiments of the present invention (not necessarily independent "units" in hardware or software), thus equally describing the functions or features of the device embodiments and the method embodiments (unit equivalent steps).
[0044] In the multiple embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the described device embodiments are merely exemplary. For example, the unit division is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutually coupled, directly coupled, or communication-connected shown or described can be realized through some interfaces. The indirect coupling or communication connection between devices or units can be realized in electronic, mechanical, or other forms.
[0045] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units. They can be located in one position or distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment solution.
[0046] In addition, the functional units in the embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more than two units can be integrated into one unit.
Claims
1. A photoconductive antenna (PCA) assembly (100) for generating THz radiation, characterized in that, The PCA component (100) includes: a semiconductor substrate (110); a plurality of antenna elements (120a to 120d), including a first antenna element (120a) and a second antenna element (120b), wherein the first antenna element (120a) and the second antenna element (120b) are arranged on the semiconductor substrate (110) to define focusing portions (130a, 130b) between the first antenna element (120a) and the second antenna element (120b); a laser for emitting laser radiation onto the focusing portions (130a, 130b); wherein the focusing portions (130a, 130b) between the first antenna element (120a) and the second antenna element (120b) include a plurality of layers arranged on the semiconductor substrate (110) between the first antenna element (120a) and the second antenna element (120b), the plurality of layers including a first epsilon-negative (ENG) metamaterial layer (131a) adjacent to the first antenna element (120a), an intermediate epsilon-near-zero (ENZ) metamaterial layer, and a second ENG metamaterial layer (131b) adjacent to the second antenna element (120b).
2. The PCA assembly (100) according to claim 1, characterized in that, The intermediate ENZ metamaterial layer includes a double-positive (DPS) metamaterial layer (135).
3. The PCA assembly (100) according to claim 1, characterized in that, In a direction extending from the first antenna element (120a) through the focusing portions (130a, 130b) to the second antenna element (120b), the thickness of the intermediate ENZ metamaterial layer is less than the sum of the thicknesses of the first ENG metamaterial layer (131a) and the second ENG metamaterial layer (131b).
4. The PCA assembly (100) according to any one of the above claims, characterized in that, The intermediate ENZ metamaterial layer extends from the semiconductor substrate (110) to a first height (h), and the first ENG metamaterial layer (131a) and / or the second ENG metamaterial layer (131b) extend to a second height (H) greater than the first height (h).
5. The PCA assembly (100) according to claim 4, characterized in that, The focusing portions (130a, 130b) further include an intermediate ENG metamaterial layer (131c) arranged on top of the intermediate ENZ metamaterial layer and between the first ENG metamaterial layer (131a) and the second ENG metamaterial layer (131b).
6. The PCA assembly (100) according to any one of the above claims, characterized in that, The first ENG metamaterial layer (131a) and the second ENG metamaterial layer (131b) include the same ENG metamaterial.
7. The PCA assembly (100) according to any one of the above claims, characterized in that, The first ENG metamaterial layer (131a) and the second ENG metamaterial layer (131b) are substantially planar layers.
8. The PCA assembly (100) according to any one of the above claims, characterized in that, The ENZ metamaterial layer further includes a graphene layer (132a) or an optically conductive material layer (132a) arranged in contact with the first ENG metamaterial layer (131a).
9. The PCA assembly (100) according to any one of the above claims, characterized in that, The ENZ metamaterial layer further includes a gold layer (132b) or a metal layer (132b) arranged to contact the second ENG metamaterial layer (131b).
10. The PCA assembly (100) according to any one of the above claims, characterized in that, The first antenna oscillator (120a) and / or the second antenna oscillator (120b) is made of gold and / or graphene.
11. The PCA assembly (100) according to any one of the above claims, characterized in that, The PCA component (100) further includes a graphene layer (136) or an optically conductive material layer (136) arranged between the first antenna oscillator (120a) and the semiconductor substrate (110) and / or a graphene layer (136) or an optically conductive material layer (136) arranged between the second antenna oscillator (120b) and the semiconductor substrate (110).
12. The PCA assembly (100) according to any one of the above claims, characterized in that, The first antenna oscillator (120a) and the second antenna oscillator (120b) define an antenna unit of the PCA component (100), and the other antenna oscillators (120c to 120d) among the plurality of antenna oscillators define one or more other antenna units of the PCA component (100), wherein the one or more other antenna units have the same configuration as the antenna unit defined by the first antenna oscillator (120a) and the second antenna oscillator (120b), and at least one of the one or more other antenna units has a different size from the antenna unit defined by the first antenna oscillator (120a) and the second antenna oscillator (120b).
13. A method (800) for generating THz radiation using a photoconductive antenna (PCA) assembly (100), characterized in that, The method (800) includes: Emitting (801) laser radiation from a laser onto a focused portion (130) of the PCA component (100), wherein the focused portion (130) is defined between a first antenna oscillator (120a) and a second antenna oscillator (120b) of the PCA component (100), and the first antenna oscillator (120a) and the second antenna oscillator (120b) are arranged on a semiconductor substrate (110) of the PCA component (100); Wherein the focused portion (130) between the first antenna oscillator (120a) and the second antenna oscillator (120b) includes a plurality of layers arranged on the semiconductor substrate (110) between the first antenna oscillator (120a) and the second antenna oscillator (120b), the plurality of layers including a first epsilon-negative (ENG) metamaterial layer (131a) adjacent to the first antenna oscillator (120a), an intermediate epsilon-near-zero (ENZ) metamaterial layer, and a second ENG metamaterial layer (131b) adjacent to the second antenna oscillator (120b).