Ultra-wideband omnidirectional duo aloe vera cruces concentrating antenna structure

Abstract

A duo-concentration antenna structure is provided, including a first conductive layer, a dielectric layer, and a second conductive layer. A first metal unit of the first conductive layer forms a first tapered hole. A second metal unit of the first conductive layer is located within the first tapered hole and forms a second tapered hole. A third metal unit and a fourth metal unit of the dielectric layer are aligned with the first metal unit and the second metal unit, respectively. The second conductive layer is connected to the dielectric layer. The first tapered hole has at least one first centerline. The second tapered hole has at least one second centerline. An angle between the at least one first centerline and the at least one second centerline is 45 degrees.

Description

[Technical Field]

[0001] This disclosure relates to a Duo Aloe Vera Cruces Concentricis antenna structure, an electromagnetic energy absorber, a thermoelectric energy harvester, a photoconductive antenna, an array antenna, and a rectenna. More specifically, this disclosure relates to an ultra-wideband omnidirectional and polarization-insensitive Duo Aloe Vera Cruces Concentricis antenna structure applied to an electromagnetic energy absorber, a thermoelectric energy harvester, a photoconductive antenna, an array antenna, and a rectenna. [Background technology]

[0002] Modern society relies heavily on battery power for ultra-low-power electronic devices, making power a limiting factor. This leads to the tedious task of disposing of and replacing a large number of batteries, which causes environmental pollution. Ambient electromagnetic (EM) energy harvesting offers an environmentally friendly and sustainable approach to this problem. To date, numerous approaches have been investigated for harvesting such freely available EM radiation energy. Among these, some research groups have proposed and experimentally demonstrated a mechanically flexible, polarization-independent, and nearly unitary broadband absorber. However, conventional broadband absorber structures only function within a limited frequency band, limiting their practical applications.

[0003] The concept of using antennas to capture EM energy has been around for decades. It involves collecting ambient EM radiation and converting it into electrical energy for powering low-power electronic devices. Energy harvesters are responsible for converting such ambient EM energy into usable electrical energy. All visible energy harvesting is primarily implemented on an industrial scale using photovoltaic (PV) and solar thermal cells. However, the performance of these cells is degraded by certain factors, such as narrowband absorption, adverse weather conditions, and daytime-only availability of visible light. Therefore, alternative approaches that can mitigate these issues are highly desirable. Furthermore, conventional solar cells do not collect a large portion of solar radiation in the IR range. To address the current renewable energy crisis, it is highly desirable to collect waste heat at infrared wavelengths and longer wavelengths and convert it into usable energy.

[0004] Considering these problems, how to establish a perfect broadband absorber that minimizes reflection and transmission and maximizes absorption bandwidth in a wide frequency range is certainly highly anticipated by the public and has become the goal and direction of related industry efforts. Summary of the Invention

[0005] According to one aspect of the present disclosure, a duo aloe vera cruciform concentric antenna structure includes a first conductive layer, a dielectric layer, and a second conductive layer. The first conductive layer includes a plurality of first metal units and a plurality of second metal units. The first metal units are arranged around each other to form a first tapered hole. The second metal units are located within the first tapered hole and are arranged around each other to form a second tapered hole. The dielectric layer is connected to the first conductive layer and includes a plurality of third metal units and a plurality of fourth metal units. The third metal units are aligned with the first metal units respectively. The fourth metal units are aligned with the second metal units respectively. The second conductive layer is connected to the dielectric layer. The dielectric layer is located between the first conductive layer and the second conductive layer. The first tapered hole has at least one first center line passing through the center of the first tapered hole. The second tapered hole has at least one second center line passing through the center of the second tapered hole. The angle between the at least one first center line and the at least one second center line is 45 degrees.

[0006] According to another aspect of the present disclosure, an electromagnetic wave energy absorber includes a nanoantenna. The nanoantenna includes at least one duo aloe vera cruciform concentric antenna structure described in the foregoing aspect. The nanoantenna is configured to absorb incident radiation, and the frequency of the incident radiation is f, satisfying 25 THz < f ≦ 800 THz.

[0007] According to yet another aspect of the present disclosure, a thermoelectric energy harvester includes a first conductive layer, a dielectric layer, a second conductive layer, a contact electrode, and a coaxial cable. The first conductive layer receives thermal radiation and includes a plurality of first metal units and a plurality of second metal units. The first metal units are arranged around each other to form a first tapered hole. The second metal units are located within the first tapered hole and are arranged around each other to form a second tapered hole. The dielectric layer is connected to the first conductive layer. The second conductive layer is connected to the dielectric layer. The dielectric layer is located between the first and second conductive layers. The contact electrode is disposed through the dielectric layer and electrically connected between the first and second conductive layers. The coaxial cable is electrically connected to the contact electrode and converts the thermal radiation into direct current according to the Seebeck effect. The first tapered hole has at least one first centerline passing through the center of the first tapered hole. The second tapered hole has at least one second centerline passing through the center of the second tapered hole. The angle between the at least one first centerline and the at least one second centerline is 45 degrees.

[0008] According to yet another aspect of the present disclosure, a photoconductive antenna is configured to replace either a spiral antenna or a bowtie antenna. The photoconductive antenna includes a first conductive layer, a light-absorbing semiconductor layer, and a second conductive layer of the duo-Aloe Vera cruces concentration antenna structure described in the previous aspect. The light-absorbing semiconductor layer is connected to the first conductive layer and has the same structure as the dielectric layer of the duo-Aloe Vera cruces concentration antenna structure described in the previous aspect. The second conductive layer is connected to the light-absorbing semiconductor layer, and the light-absorbing semiconductor layer is located between the first and second conductive layers.

[0009] According to yet another aspect of the present disclosure, an array antenna includes a plurality of the duo-aloe vera cruces concentrisis antenna structures described in the preceding aspect. The plurality of first conductive layers of the duo-aloe vera cruces concentrisis antenna structure are spaced apart. The plurality of dielectric layers of the duo-aloe vera cruces concentrisis antenna structure are spaced apart. The plurality of second conductive layers of the duo-aloe vera cruces concentrisis antenna structure are connected to each other or integrally formed.

[0010] According to yet another aspect of the present disclosure, a rectenna for use in a communications or energy harvesting device includes the antenna structure of the previous aspect and a rectifier module. The antenna structure receives a radio frequency signal or radiation. The rectifier module is electrically connected to the antenna structure and converts the radio frequency signal or radiation from alternating current to direct current. [Brief explanation of the drawings]

[0011] A more complete understanding of the present disclosure can be obtained by reading the following detailed description of the embodiments in conjunction with the accompanying drawings, in which:

[0012] [Figure 1A] FIG. 1 shows a three-dimensional schematic diagram of a duo-Aloe vera cruces concentris antenna structure according to a first embodiment of the present disclosure. [Figure 1B] Figure 1A shows an exploded view of the duo-Aloe vera cruces concentricus antenna structure. [Figure 1C] Figure 1A shows a top view of the duo-Aloe vera cruces concentris antenna structure. [Figure 2A] Figure 1A shows a three-dimensional schematic diagram of the first conductive layer of the duo-Aloe vera cruces concentris antenna structure. [Figure 2B]2B shows a top view (in the xy plane) of the first conductive layer of FIG. 2A. [Figure 3] FIG. 4 shows a schematic diagram of an electromagnetic wave energy absorber according to a second embodiment of the present disclosure. [Figure 4] FIG. 10 shows a schematic diagram of a thermoelectric energy harvester according to a third embodiment of the present disclosure. [Figure 5] FIG. 10 shows a schematic diagram of a photoconductive antenna according to a fourth embodiment of the present disclosure. [Figure 6] FIG. 10 shows a two-dimensional schematic diagram of an array antenna according to a fifth embodiment of the present disclosure. [Figure 7A] Figure 1 shows the reflectance, transmittance, and absorptance curves of the duo-Aloe vera cruces concentration antenna structure at normal incidence of a plane wave. [Figure 7B] 1 shows the curves of reflectivity, transmittance, and absorption of an array antenna at normal incidence of a plane wave. [Figure 8A] Figure 1 shows the curve diagram of real and imaginary parts of impedance of the duo-Aloe vera cruces concentris antenna structure. [Figure 8B] 1 shows a curve diagram of the real and imaginary parts of the impedance of an array antenna. [Figure 9A] A top view of the electric field distribution of the duo-Aloe vera cruces concentris antenna structure is shown. [Figure 9B] Cross-sectional view of the electric field distribution of the duo-Aloe vera cruces-concentration antenna structure. [Figure 10] Figure 1 shows the power flow curves across different depths of the Duo-Aloe Vera Cruces Concentration Antenna structure at 278.5 THz. [Figure 11A] Figure 1 shows the curve diagram of absorption spectrum of duo-Aloe vera cruces concentration antenna structure with different incident angles from 0° to 75° in transverse electric mode. [Figure 11B] Figure 1 shows the curves of absorption spectra of duo-Aloe vera cruces concentration antenna structure with different incident angles from 0° to 75° in transverse magnetic mode. [Figure 11C] Figure 1 shows the curve diagram of absorption spectrum of duo-Aloe vera cruces concentration antenna structure with different polarization angles from 0° to 90° of transverse electric mode. [Figure 11D] Figure 1 shows the curve diagram of absorption spectrum of duo-Aloe vera cruces concentration antenna structure with different polarization angles from 0° to 90° of transverse magnetic mode. [Figure 12A] A three-dimensional schematic of the far-field directivity of the duo-Aloe vera cruces concentra- tion antenna structure at 278.5 THz is shown. [Figure 12B] Figure 1 shows a polar plot of the far-field directivity of the duo-Aloe vera cruces concentra- tion antenna structure at 278.5 THz. [Figure 13A] A three-dimensional schematic diagram of the gain of the duo-Aloe vera cruces concentrating antenna structure at 278.5 THz is shown. [Figure 13B] Figure 1 shows a polar plot of the gain of the duo-Aloe vera cruces concentrating antenna structure at 278.5 THz. [Figure 14] 10 shows a schematic diagram of a rectenna according to a sixth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] The embodiments are described using drawings. For clarity, some practical details are described below. However, it should be noted that the present disclosure should not be limited by the practical details, i.e., in some embodiments, the practical details are unnecessary. Furthermore, to simplify the drawings, some conventional structures and elements are simply illustrated, and duplicated elements may be represented by the same reference numerals.

[0014] When an element (or device) is described as being "connected" to another element, the element may be directly connected to the other element or indirectly connected to the other element, i.e., there may be intervening elements. In contrast, when an element is described as being "directly connected" to another element, it will be understood that there are no intervening elements. Furthermore, although terms such as first, second, and third are used herein to describe various elements or components, these elements or components should not be limited by these terms. Thus, a first element or component described below may also be referred to as a second element or component.

[0015] Please refer to Figures 1A, 1B, and 10. Figure 1A shows a three-dimensional schematic diagram of a duo-aloe vera cruces concentration antenna structure 100 according to a first embodiment of the present disclosure. Figure 1B shows an exploded view of the duo-aloe vera cruces concentration antenna structure 100 of Figure 1A. Figure 1C shows a top view of the duo-aloe vera cruces concentration antenna structure 100 of Figure 1A. In Figures 1A, 1B, and 1C, the duo-aloe vera cruces concentration antenna structure 100 includes a first conductive layer 200, a dielectric layer 300, and a second conductive layer 400.

[0016] The first conductive layer 200 includes a plurality of first metal units 210 and a plurality of second metal units 220. The first metal units 210 are arranged around each other to form a first tapered hole 230. The second metal units 220 are located within the first tapered hole 230 and are arranged around each other to form a second tapered hole 240.

[0017] The dielectric layer 300 is connected to the first conductive layer 200 and includes a plurality of third metal units 310 and a plurality of fourth metal units 320. The third metal units 310 are arranged around each other to form a third tapered hole 330. The fourth metal units 320 are located within the third tapered hole 330 and arranged around each other to form a fourth tapered hole 340. Furthermore, the third metal units 310 are aligned with the first metal units 210, respectively. The fourth metal units 320 are aligned with the second metal units 220, respectively.

[0018] The second conductive layer 400 is connected to the dielectric layer 300. The dielectric layer 300 is located between the first conductive layer 200 and the second conductive layer 400. The second conductive layer 400 may include a surface 401. Each of the first metal units 210 and each of the third metal units 310 are stacked to cover the surface 401, and each of the second metal units 220 and each of the fourth metal units 320 are stacked to cover the surface 401. In other words, the pattern of the first conductive layer 200 is the same as the pattern of the dielectric layer 300.

[0019] It is worth noting that the first tapered hole 230 has at least one first centerline CL1 passing through the center of the first tapered hole 230. The second tapered hole 240 has at least one second centerline CL2 passing through the center of the second tapered hole 240. The centers of the first tapered hole 230 and the second tapered hole 240 are the same, and this center is in the center of the first conductive layer 200. In particular, the number of the at least one first centerline CL1 is two, and the number of the at least one second centerline CL2 is two. The two first centerlines CL1 are perpendicular to each other, and the two second centerlines CL2 are perpendicular to each other. It is worth noting that the angle θ between the at least one first centerline CL1 and the at least one second centerline CL2 is 45 degrees. Similar to the first conductive layer 200, the third tapered hole 330 of the dielectric layer 300 has at least one third centerline (not shown) passing through the center of the third tapered hole 330, and the fourth tapered hole 340 of the dielectric layer 300 has at least one fourth centerline (not shown) passing through the center of the fourth tapered hole 340, and the angle between the at least one third centerline and the at least one fourth centerline is 45 degrees.

[0020] In particular, the duo aloe vera cruces concentration antenna structure 100 of the present disclosure can be applied to an EM wave absorber for electromagnetic (EM) energy harvesting. A perfect EM wave absorber is a device in which all incident radiation is efficiently absorbed at the operating wavelength. When radiation is absorbed by this device, it is converted into ohmic heat or other forms of energy. Therefore, reflection, transmission, scattering, and all other wave propagation are not observed when waves pass through a perfect EM wave absorber. While conventional absorbers are generally made of materials with high intrinsic loss, the duo aloe vera cruces concentration antenna structure 100 of the present disclosure can be made primarily of precious metals.

[0021] Specifically, the first conductive layer 200 is made of a lossy metal, nickel (Ni). The dielectric layer 300 is made of a highly insulating material, which is SU-8. The second conductive layer 400 is made of a lossy metal, gold (Au). The first conductive layer 200 and the dielectric layer 300 are patterned, while the second conductive layer 400 is unpatterned and remains a continuous layer to avoid EM wave transmission. The dielectric layer 300 is sandwiched between the first conductive layer 200 and the second conductive layer 400. The properties of the aforementioned materials are listed in Table 1, but the present disclosure is not limited thereto.

[0022] [Table 1]

[0023] Furthermore, the thickness of the first conductive layer 200 is Z1, the thickness of the dielectric layer 300 is Z2, and the thickness of the second conductive layer 400 is Z3, satisfying Z1=Z3≦Z2. The thickness Z1 of the first conductive layer 200 is greater than the skin depth of the first conductive layer 200, the thickness Z2 of the dielectric layer 300 is greater than the penetration depth of the dielectric layer 300, and the thickness Z3 of the second conductive layer 400 is greater than the skin depth of the second conductive layer 400. In the first embodiment, the thickness Z1 of the first conductive layer 200 and the thickness Z3 of the second conductive layer 400 are 200 nm. The thickness Z2 of the dielectric layer 300 is 500 nm, and the relative dielectric constant (ε r ) is 2.8. The total thickness of the duo-aloe vera cruces concentris antenna structure 100 is 900 nm. The length L and width W of the duo-aloe vera cruces concentris antenna structure 100 are both 1000 nm, although the present disclosure is not limited thereto.

[0024] See Figures 1C, 2A, and 2B. Figure 2A shows a three-dimensional schematic diagram of the first conductive layer 200 of the dual Aloe vera cruces concentration antenna structure 100 of Figure 1A. Figure 2B shows a top view (in the xy plane) of the first conductive layer 200 of Figure 2A. As shown in Figures 1C and 2A, each first metal unit 210 may include a curved surface 211. The curved surfaces 211 of two adjacent first metal units 210 are connected to each other. The curved surfaces 211 of the first metal units 210 form four peaks 212. Two of the peaks 212 are on one side of the first center line CL1, and the other two of the peaks 212 are on the other side of the first center line CL1.

[0025] Furthermore, each second metal unit 220 may include an outer curved surface 221 and an inner curved surface 222. The outer curved surface 221 and the inner curved surface 222 form a leaf pattern on the surface of the first conductive layer 200. The inner curved surfaces 222 of two adjacent second metal units 220 are connected to each other. The inner curved surfaces 222 of the second metal units 220 form four peaks 223, two of which are on one side of the second center line CL2, and the other two of which are on the other side of the second center line CL2.

[0026] Specifically, the structure of the first conductive layer 200 is tapered in a manner that creates four identical petals (i.e., first metal units 210). The identical petals surround four identical leaf patterns (i.e., second metal units 220) in the center of the first conductive layer 200. Each second metal unit 220 near the center of the first conductive layer 200 is designed using a six-spline curve in SOLIDWORKS®, and then the structure formed by the second metal units 220 is rotated 90° relative to the structure formed by the first metal units 210. Similarly, the structure of the dielectric layer 300 will not be described again herein. Therefore, such a tapered structure of the duo-aloe vera cruces concentration antenna structure 100 of the present disclosure, in combination with a nanoantenna, can confine infrared (IR), the entire visible light, and a portion of the UV-visible light band. Furthermore, the duo aloe vera cruces concentricity antenna structure 100 includes a metal-dielectric-metal (MDM) configuration in which both the first conductive layer 200 and the dielectric layer 300 are tapered to create a groove-like structure (e.g., Duo Aloe Vera cruces Concentricis in Latin) that can confine and cover wavelengths of different frequencies. The symmetrical structure of the duo aloe vera cruces concentricity antenna structure 100 ensures that polarization is not a factor in detecting plane waves. For EM wave absorption, the second metal unit 220 on the inside of the first conductive layer 200 covers the high-frequency regime, and the first metal unit 210 on the outside of the first conductive layer 200 covers the low-frequency regime. The duo aloe vera cruces concentricity antenna structure 100 of the present disclosure will be described in more detail with the following figures and embodiments.

[0027] The tapered structure of the first conductive layer 200 is defined as an exponential curve in the xy plane, as shown in FIG. 2B. For each first metal unit 210, the profile of the curved surface 211 may be an exponential taper. The exponential taper is defined by the aperture ratio R and two points P1 and P2 in the xy plane,

number

[0028] In equations (1), (2), and (3), the aperture ratio R is represented as R. The x coordinate in the xy plane is represented as x. The y coordinate in the xy plane is represented as y. The x coordinate of point P1 is represented as x1. The y coordinate of point P1 is represented as y1. The x coordinate of point P2 is represented as x2. The y coordinate of point P2 is represented as y2. The first variable value is represented as C1, and the second variable value is represented as C2.

[0029] As shown in Figure 2B, the length l of the taper is x2-x1. For the profile of the curved surface 211, the aperture ratio R is 0 to 0.7. In the limit where the aperture ratio R approaches zero, the exponential taper produces a so-called linearly tapered slot antenna with a constant taper slope. For example,

number

number

[0030] For the exponential taper defined by equation (1), the taper slope (i.e., S) varies continuously from S1 to S2, where S1 and S2 are the taper slopes at x = x1 and x = x2, respectively. If R > 0, then S1 <S<S2である。

[0031] Similarly, for each second metal unit 220, the profiles of both the outer curved surface 221 and the inner curved surface 222 may be another exponential taper. The other exponential taper is defined by the aperture ratio R′ and two points P2 and P2′ in the xy plane,

number

[0032] In equations (7), (8), and (9), the aperture ratio R' is represented as R'. The x coordinate in the xy plane is represented as x. The y coordinate in the xy plane is represented as y. The x coordinate of point P2 is represented as x2. The y coordinate of point P2 is represented as y2. The x coordinate of point P2' is represented as x2'. The y coordinate of point P1 is represented as y2'. The first variable value is represented as C1', and the second variable value is represented as C2'.

[0033] 2B, the length l' of the taper is x2'-x2. The opening ratio R' of the profile of the outer curved surface 221 is 0 to 0.7, similar to the opening ratio R corresponding to the profile of the curved surface 211.

number

number

[0034] In the case of another exponential function taper defined by Equation (7), the taper gradient (i.e., S’) continuously changes from S1’ to S2’, where S1’ and S2’ are the taper gradients at x = x2 and x = x2’, respectively, and when R’>0, S1’ < S’ < S2’. The parameters and dimensions of the first conductive layer 200 are listed in Table 2, but the present disclosure is not limited thereto.

[0035] [Table 2]

[0036] Please refer to FIG. 3. FIG. 3 is a schematic diagram of an electromagnetic wave energy absorber 500 according to the second embodiment of the present disclosure. The electromagnetic wave energy absorber 500 includes a nanoantenna 510. The nanoantenna 510 includes at least one duo-aloe vera-crucifixus-concentricus antenna structure 511. In the second embodiment, the number of at least one duo-aloe vera-crucifixus-concentricus antenna structure 511 may be plural, and each duo-aloe vera-crucifixus-concentricus antenna structure 511 is the same as the duo-aloe vera-crucifixus-concentricus antenna structure 100 of the first embodiment. The nanoantenna 510 is configured to absorb the incident radiation Ri, the frequency of the incident radiation Ri is f, and 25 THz < f ≦ 800 THz is satisfied. The incident radiation Ri is incident on the nanoantenna 510 in the normal direction, and the nanoantenna 510 has an average absorption corresponding to the incident radiation Ri. The average absorption is AA, and 84.5% ≦ AA is satisfied. In particular, the nanoantenna 510 is based on the duo-aloe vera-crucifixus-concentricus antenna structure 100, and as a result of numerical analysis, it is shown to be a promising candidate for the application of energy harvesting from infrared (IR) to ultraviolet (UV) regime. As a result of testing and simulating the influence on the absorption performance of the electromagnetic wave energy absorber 500, high performance is shown in both the bandwidth and the absorption rate (as shown in FIGS. 7A and 7B in the next paragraph, the average absorption over a wide range from IR to visible light, that is, from 25 THz to 800 THz, is 83.4 to 84.5%). In other embodiments, the duo-aloe vera-crucifixus-concentricus antenna structure 511 can also be used in an energy harvesting device used in an antenna. For example, broadband energy harvesting combined with an antenna can be realized by directly harvesting RF energy into DC using a rectifier, thermoelectric, bolometer, pyroelectric, or a quantum type detector such as InGaAs, photoconductive material.

[0037] Please refer to FIG. 4. FIG. 4 shows a schematic diagram of a thermoelectric energy harvester 600 according to a third embodiment of the present disclosure. The thermoelectric energy harvester 600 includes a first conductive layer 610, a dielectric layer 620, a second conductive layer 630, a contact electrode 640, and a coaxial cable 650. The structural configuration between the first conductive layer 610, the dielectric layer 620, and the second conductive layer 630 is the same as the structural configuration between the corresponding elements of the duo-aloe vera cruces concentration antenna structure 100 of the first embodiment, and will not be described again herein. However, the dimensions of the first conductive layer 610, the dielectric layer 620, and the second conductive layer 630 may be the same as or different from the corresponding elements of the duo-aloe vera cruces concentration antenna structure 100 of the first embodiment.

[0038] Note that the dielectric layer 620 in Figure 4 is a perspective view. The first conductive layer 610 receives the thermal radiation Rh. The contact electrode 640 is disposed through the dielectric layer 620 and is electrically connected between the first conductive layer 610 and the second conductive layer 630. The coaxial cable 650 is electrically connected to the contact electrode 640 and converts the thermal radiation Rh into direct current DC according to the Seebeck effect (diffusion of electrons by the thermal radiation Rh). The direct current DC is applied to a load Rh. L is supplied to the load R L Provides power to.

[0039] The thermoelectric energy harvester 600 is a portable or wearable thermoelectric generator that can harvest ambient energy from its surroundings using a flexible, electrically conductive thermoelectric material and an ultra-wideband antenna as one heat-receiving end of a thermoelectric (TE) module. A TE module is essentially a circuit made of two different thermoelectric materials, which, when combined, can generate electricity directly from heat. The TE module consists of two different thermoelectric materials joined at their ends. One end is made from an N-type (electron-rich) semiconductor, and the other end is made from a P-type (electron-deficient) semiconductor. Specifically, the first conductive layer 610 is made from a P-type semiconductor, and the second conductive layer 630 is made from an N-type semiconductor. In particular, the P-type semiconductor of the first conductive layer 610 is made from nickel or one of several P-type conductive materials, and the N-type semiconductor of the second conductive layer is made from gold or one of several N-type conductive materials. The first conductive layer 610 utilizes two concentric tapered cross structures as the heat receiving end of the thermoelectric energy harvester 600 to improve energy absorption and frequency range.

[0040] Please refer to FIG. 5. FIG. 5 shows a schematic diagram of a photoconductive antenna 700 according to a fourth embodiment of the present disclosure. The photoconductive antenna 700 includes a first conductive layer 710, a light-absorbing semiconductor layer 720, and a second conductive layer 730, and is configured to replace either a spiral antenna (not shown) or a bowtie antenna (not shown). The first conductive layer 710 is the same as the first conductive layer 200 of the duo-aloe vera cruces concentration antenna structure 100 of the first embodiment. The light-absorbing semiconductor layer 720 is connected to the first conductive layer 710 and has the same structure as the dielectric layer 300 of the duo-aloe vera cruces concentration antenna structure 100 of the first embodiment. The second conductive layer 730 is connected to the light-absorbing semiconductor layer 720 and has the same structure as the second conductive layer 400 of the duo-aloe vera cruces concentration antenna structure 100 of the first embodiment. The light-absorbing semiconductor layer 720 is located between the first conductive layer 710 and the second conductive layer 730. That is, the structural configuration between the first conductive layer 710, the light-absorbing semiconductor layer 720, and the second conductive layer 730 is the same as the structural configuration between the first conductive layer 200, the dielectric layer 300, and the second conductive layer 400 of the dual-concentration antenna structure 100 of the first embodiment, and will not be described again herein. As shown in FIG. 5 , the photoconductive antenna 700 receives a laser pulse Lp, which excites carriers accelerated by a potential +V. The resulting charge separation generates dipole radiation at terahertz frequencies. Specifically, the photoconductive antenna 700 essentially uses the photoconductive effect to generate electrical energy and transmit and receive radiation (typically in the THz range). Photoconductive antenna 700 consists of a metal antenna (i.e., first conductive layer 710 and light-absorbing semiconductor layer 720) patterned on a photoconductive substrate (i.e., second conductive layer 730). In the fourth embodiment, photoconductive antenna 700 is used as a transmitting and receiving system rather than as an energy harvesting device.

[0041] Please refer to Figures 1A and 6. Figure 6 shows a two-dimensional schematic diagram of an array antenna 800 according to a fifth embodiment of the present disclosure. The array antenna 800 includes a plurality of duo-aloe vera cruces concentris antenna structures 100 of the first embodiment. Specifically, the array antenna 800 is composed of a 3x3 array of the duo-aloe vera cruces concentris antenna structures 100. In other words, the duo-aloe vera cruces concentris antenna structure 100 is the unit cell antenna structure of the array antenna 800. Regarding the structure of the array antenna 800, the first conductive layers 200 of the duo-aloe vera cruces concentris antenna structures 100 are spaced apart, and the dielectric layers 300 of the duo-aloe vera cruces concentris antenna structures 100 are spaced apart. The second conductive layers 400 of the duo Aloe Vera Cruces concentration antenna structure 100 are connected to each other or integrally formed. A slot 810 having a width 811 is disposed between each pair of first conductive layers 200. The multiple slots 810 are connected to each other in a lattice pattern. The width 811 of each slot 810 is the same, and each width 811 of the slots 810 is 100 nm. In another embodiment, the voltage output can be increased by electrically connecting the first conductive layers of the duo Aloe Vera Cruces concentration antenna structure in series and the dielectric layers of the duo Aloe Vera Cruces concentration antenna structure in series. Alternatively, the output current can be increased by connecting the first conductive layers of the duo Aloe Vera Cruces concentration antenna structure in parallel and the dielectric layers of the duo Aloe Vera Cruces concentration antenna structure in parallel.

[0042] In the following sections, the characteristics of the duo-aloe vera cruces concentration antenna structure 100 and the array antenna 800 are tested and the results are discussed.

[0043] <Reflectance, transmittance, and absorption tests> To clarify the physical origin of ultra-wideband (UWB) absorption, the duo-aloe vera cruces-concentration antenna structure 100 and the array antenna 800 are tested at normal incidence to obtain reflectivity, transmittance, and absorptance. See Figures 7A and 7B. Figure 7A shows the reflectivity, transmittance, and absorptance curves of the duo-aloe vera cruces-concentration antenna structure 100 at normal incidence of a plane wave, and Figure 7B shows the reflectivity, transmittance, and absorptance curves of the array antenna 800 at normal incidence of a plane wave. Figures 7A and 7B show that the duo-aloe vera cruces-concentration antenna structure 100 has an excellent absorption bandwidth from 25 THz to 800 THz, reaching 775 THz with an absorptance of 84.5%. The absorption performance of the array antenna 800 is not significantly different from that of the duo-aloe vera cruces-concentration antenna structure 100, and shows almost the same tendency as the duo-aloe vera cruces-concentration antenna structure 100. The array antenna 800 can achieve an average absorption rate of 83.4% within the operating frequency band.

[0044] This UWB and high absorption is due to mutual coupling and overlap between successive resonances within the duo-aloe-vera-cruces-concentration antenna structure 100. The interaction of the incident wave with the tapered structure of the duo-aloe-vera-cruces-concentration antenna structure 100 increases the energy dissipation of the antenna. In this case, most reflected waves are destructively coherent with each other within the operating frequency range, reducing the amount of incident wave reflected from the surface and achieving broadband absorption.

[0045] <Impedance Test> Please refer to Figures 8A and 8B. Figure 8A shows the curves of the real and imaginary parts of the impedance of the duo-aloe vera cruces concentrating antenna structure 100. Figure 8B shows the curves of the real and imaginary parts of the impedance 800 of the array antenna. In Figures 8A and 8B, the more the relative impedance of the absorber (i.e., the duo-aloe vera cruces concentrating antenna structure 100 and the array antenna 800) matches that of free space, the higher the absorption rate of the absorber. In general, the mechanism for wideband and high absorption at radio frequencies (RF) is very simple. At radio frequencies, metals behave like perfect conductors, and the skin depth becomes negligible compared to the size of the antenna.

[0046] When an incident wave propagates as a plane wave on the tapered structure of the duo aloe vera cruces concentration antenna structure 100, it is reflected or absorbed depending on the mismatch between the impedance of this structure and that of free space. The strong impedance matching between the array antenna 800 and the surrounding free space is the reason for this wideband characteristic. Since the second conductive layer 400 of the duo aloe vera cruces concentration antenna structure 100 is sufficiently larger than the skin depth in the operating frequency regime, the transmission becomes negligible (almost zero) and the structure absorption becomes high.

[0047] <Field distribution test> To understand the fundamental physics behind such ultra-broadband absorption, we study the electric field distribution of the duo-aloe vera cruces concentrating antenna structure 100. See Figures 9A and 9B. Figure 9A shows a top view of the electric field distribution of the duo-aloe vera cruces concentrating antenna structure 100. Figure 9B shows a cross-sectional view of the electric field distribution of the duo-aloe vera cruces concentrating antenna structure 100. In Figures 9A and 9B, one specific frequency, 278.5 THz, is selected to observe the top view of the electric field distribution in the xy plane (z = 0.9 μm) and the cross-sectional view of the electric field distribution in the yz plane (x = 0.141 μm), respectively. It is observed that most of the electric field is confined to the surfaces of both the first metal unit 210 and the second metal unit 220. The electric field is strong on the surfaces of both the first metal unit 210 and the second metal unit 220, which means there is mutual influence between two adjacent first metal units 210 and between two adjacent second metal units 220. It can also be seen that the electric field is significantly reduced as the EM wave propagates inside the duo-aloe vera cruces concentrision antenna structure 100 and nearly vanishes when it reaches the bottom second conductive layer 400 (not shown in FIG. 9B). Therefore, the UWB absorption of the duo-aloe vera cruces concentrision antenna structure 100 is suggested by the continuous electromagnetic resonance of the metallic phase Ni generated at multiple frequency points (170 THz to 800 THz), resulting in efficient UWB absorption in the operating frequency regime.

[0048] <Power flow test> See FIG. 10. FIG. 10 shows a curve diagram of power flow through different depths of the duo-aloe vera cruces concentration antenna structure 100 at 278.5 THz. In FIG. 10, the excitation power used for the test is 1.0 Watt. It is clear that a significant amount of power (0.8 Watts at the surface) is absorbed by the first conductive layer 200, and a negligible amount of power is absorbed by the dielectric layer 300 and the second conductive layer 400. The absorption of the duo-aloe vera cruces concentration antenna structure 100 is mainly due to ohmic or resistive losses in the first conductive layer 200. Most of the absorption occurs in the first conductive layer 200, which can be translated into a temperature rise in the tap metal film of the first conductive layer 200.

[0049] <Transverse Electric (TE) and Transverse Magnetic (TM) Mode Tests> In practical applications, polarization-independent performance and a wide incident angle are crucial because the incident wave may be obliquely incident on the device in some situations. Therefore, the polarization insensitivity of the duo-Aloe Vera Cruces concentrating antenna structure 100 is tested at both normal and oblique incidence. See Figures 11A, 11B, 11C, and 11D. Figure 11A shows the absorption spectrum of the duo-Aloe Vera Cruces concentrating antenna structure 100 at different incident angles θ from 0° to 75° for the TE mode. Figure 11B shows the absorption spectrum of the duo-Aloe Vera Cruces concentrating antenna structure 100 at different incident angles θ from 0° to 75° for the TM mode. Figure 11C shows the absorption spectrum of the duo-Aloe Vera Cruces concentrating antenna structure 100 at different polarization angles Φ from 0° to 90° for the TE mode. FIG. 11D shows the curve diagram of the absorption spectrum of the duo-Aloe vera cruces concentration antenna structure 100 with different polarization angles Φ from 0° to 90° of the TM mode.

[0050] 11A and 11B, it can be seen that the duo-Aloe vera cruces concentrating antenna structure 100 maintains an average absorption of greater than 82.7% in TE mode and greater than 83.5% in TM mode across the operating frequency range for incident waves obliquely incident up to 45°, with no apparent change in absorption performance. Thus, the duo-Aloe vera cruces concentrating antenna structure 100 of the present disclosure is polarization insensitive up to 45° in both TE and TM modes. The unique mechanism of coupling between the associated electric and magnetic resonances and the free-space incident light is attributed to angle-independent absorption.

[0051] 11C and 11D, it is clear that the average absorption remains unchanged, maintaining over 83.91% in TE mode and over 83.92% in TM mode, up to 90° under normal plane wave incidence. This result is attributed to the structure's extremely high polarization insensitivity up to 90° under normal plane wave incidence in both TE and TM modes. From the above results, it can be concluded that TE becomes TM at Φ = 90°, and vice versa. The polarization insensitivity of the duo-Aloe Vera Cruces concentration antenna structure 100 is mainly due to the symmetrical arrangement of the tapered structure between the first metal unit 210 and the second metal unit 220. Based on the above numerical results, it is clear that the duo-Aloe Vera Cruces concentration antenna structure 100 of the present disclosure is polarization-independent under both normal and oblique plane wave incidence, maintaining the absorption performance of both TE and TM modes within the operating frequency band.

[0052] Far-field directivity and gain testing See Figures 12A, 12B, 13A, and 13B. Figure 12A shows a three-dimensional schematic diagram of the far-field directivity of the duo Aloe Vera Cruces concentrating antenna structure 100 at 278.5 THz. Figure 12B shows a polar plot of the far-field directivity of the duo Aloe Vera Cruces concentrating antenna structure 100 at 278.5 THz. Figure 13A shows a three-dimensional schematic diagram of the gain of the duo Aloe Vera Cruces concentrating antenna structure 100 at 278.5 THz. Figure 13B shows a polar plot of the gain of the duo Aloe Vera Cruces concentrating antenna structure 100 at 278.5 THz. In Figures 12A and 12B, the obtained numerical results highlight that the radiation pattern exhibits a maximum directivity value of 6.01 dBi. The half-power beam width (HPBW) or 3 dB bandwidth of the duo aloe vera cruces concentris antenna structure 100 at 278.5 THz is 209.8°, which is large enough to ensure that the duo aloe vera cruces concentris antenna structure 100 is omnidirectional. The high directivity and beamwidth of the duo aloe vera cruces concentris antenna structure 100 at 278.5 THz are due to the symmetrical petal shape. Furthermore, the absence of nulls and lobes in the pattern results in an omnidirectional radiation pattern. Therefore, the absence of lobes and nulls in the pattern of the first conductive layer 200 maximizes directivity, improving the performance of the duo aloe vera cruces concentris antenna structure 100.

[0053] The gain of the duo-aloe-vera-cruces-concentration antenna structure 100 is a measure of the maximum efficiency with which the duo-aloe-vera-cruces-concentration antenna structure 100 can radiate or absorb power supplied or received from an external power or radiation source. More specifically, it is defined as the maximum radiation intensity generated / absorbed by the duo-aloe-vera-cruces-concentration antenna structure 100 compared to the radiation intensity provided by a lossless isotropic antenna from which the same amount of power is supplied or received. In Figures 13A and 13B, the duo-aloe-vera-cruces-concentration antenna structure 100 of the present disclosure provides an optimal gain of 0.464 dB and a wider 3 dB bandwidth of 209.8°. A gain of 0.464 dB means that 1.112 times more effective power can be received by the duo-aloe-vera-cruces-concentration antenna structure 100 than from an isotropic antenna.

[0054] See FIG. 14 , which shows a schematic diagram of a rectenna 900 according to a sixth embodiment of the present disclosure. The rectenna 900 can be used in a communication or energy harvesting device and may include a duo-aloe vera cruces concentration antenna structure 910 and a rectifier module 920. The duo-aloe vera cruces concentration antenna structure 910 may include a first conductive layer 911, a dielectric layer 912, and a second conductive layer 913. The structural configuration between the first conductive layer 911, the dielectric layer 912, and the second conductive layer 913 is the same as the structural configuration between the corresponding elements of the duo-aloe vera cruces concentration antenna structure 100 of the first embodiment, and will not be described again herein.

[0055] The first conductive layer 911 of the duo aloe vera cruces concentris antenna structure 910 receives a radio frequency signal Rf or radiation (not shown). The rectifier module 920 is electrically connected to the second conductive layer 913 of the duo aloe vera cruces concentris antenna structure 910 and converts the radio frequency signal Rf or radiation from alternating current AC to direct current DC. The direct current DC is then applied to a load R Lis supplied to the load R L 14 , the radio frequency signal Rf can be converted from alternating current (AC) to direct current (DC) by connecting the duo-aloe vera cruces concentris antenna structure 910 to a rectifier module 920. In FIG. 4 , radio frequency radiation (not shown) can be absorbed by the thermoelectric energy harvester 600 and converted to direct current (DC) using rectification.

[0056] In summary, the present disclosure has the following advantages. First, the duo-Aloe Vera Cruces concentrating antenna structure has an excellent absorption bandwidth of 84.5% from 25 to 800 THz under normal incidence, reaching 775 THz. Second, the duo-Aloe Vera Cruces concentrating antenna structure produces less than 5% absorption deviation between 45° incidence angles from normal and 0.05% absorption deviation between 0° and 90° polarization in both TE and TM modes. Third, the duo-Aloe Vera Cruces concentrating antenna structure is omnidirectional with a HPBW or 3 dB bandwidth of 209.8° at 278.5 THz.

[0057] Although the present disclosure has been described in considerable detail with reference to particular embodiments, other embodiments are possible, and therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.

[0058] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of the present disclosure provided they fall within the scope of the following claims.

Claims

1. a plurality of first metal units arranged around one another to form a first tapered hole; and a plurality of second metal units positioned within the first tapered hole and arranged around one another to form a second tapered hole; a first conductive layer; a plurality of third metal units connected to the first conductive layer and aligned with each of the first metal units; and a plurality of fourth metal units aligned with each of the second metal units; a dielectric layer; a second conductive layer connected to the dielectric layer, the dielectric layer being located between the first conductive layer and the second conductive layer; a second conductive layer; The duo aloe vera cruces concentration antenna structure, wherein the first tapered hole has at least one first centerline passing through the center of the first tapered hole, and the second tapered hole has at least one second centerline passing through the center of the second tapered hole, and the angle between the at least one first centerline and the at least one second centerline is 45 degrees.

2. 2. The duo Aloe Vera Cruces concentration antenna structure of claim 1, wherein the number of the at least one first center line is two, the number of the at least one second center line is two, the first center lines are perpendicular to each other, and the second center lines are perpendicular to each other.

3. 3. The duo aloe vera cruces concentration antenna structure of claim 2, wherein each of the first metal units includes a curved surface, and the curved surfaces of two adjacent first metal units are connected to each other, and the curved surfaces of the first metal units form a plurality of peaks, two of the peaks being on one of the first center lines, and another two of the peaks being on the other of the first center lines.

4. the profile of the curved surface is an exponential taper, the exponential taper being defined by an aperture ratio and two points in an xy plane; [Equation 1] Fulfilling In the formula, the aperture ratio is represented as R and is between 0 and 0.7, the x coordinate of the xy plane is represented as x, the y coordinate of the xy plane is represented as y, and the x coordinate of one of the two points is x １ and the y coordinate of one of the two points is expressed as y １ and the x-coordinate of the other of the two points is x ２ and the y coordinate of the other of the two points is y ２ and the first variable value is C １ and the second variable value is C ２ 4. The duo aloe vera cruces concentration antenna structure of claim 3, represented as: 【Request 5】 【Number 2】 If the taper slope of the exponential taper is determined to be S, then the exponential taper x = x １ The first taper gradient at S １ and the exponential taper x=x ２ The second taper gradient at S ２ and the taper flare angle of the exponential taper is represented as α; [Equation 3] The duo aloe vera cruces concentration antenna structure according to claim 4, which satisfies the above.

6. 3. The duo aloe vera cruces concentration antenna structure of claim 2, wherein each of the second metal units includes an outer curved surface and an inner curved surface, the outer curved surface and the inner curved surface form a leaf pattern, the inner curved surfaces of two adjacent second metal units are connected to each other, and the inner curved surfaces of the second metal units form a plurality of peaks, two of the peaks are on one of the second center lines, and another two of the peaks are on the other of the second center lines.

7. 3. The duo aloe vera cruces concentration antenna structure of claim 2, wherein the third metal units are arranged around each other to form a third tapered hole, the fourth metal units are located within the third tapered hole and arranged around each other to form a fourth tapered hole, the third tapered hole has at least one third centerline passing through the center of the third tapered hole, the fourth tapered hole has at least one fourth centerline passing through the center of the fourth tapered hole, and an angle between the at least one third centerline and the at least one fourth centerline is 45 degrees.

8. 2. The duo aloe vera cruces concentration antenna structure of claim 1, wherein the second conductive layer includes a surface, one of the first metal units and one of the third metal units are stacked to cover the surface, and one of the second metal units and one of the fourth metal units are stacked to cover the surface.

9. 2. The duo aloe vera cruces concentration antenna structure of claim 1, wherein said dielectric layer is made of a high insulating material, and said high insulating material is SU-8.

10. The thickness of the first conductive layer is Z １ and the thickness of the dielectric layer is Z ２ and the thickness of the second conductive layer is Z ３ and Z １ =Z ３ ≦Z ２ The duo aloe vera cruces concentration antenna structure according to claim 1, which satisfies the above.

11. 11. The duo aloe vera cruces concentration antenna structure of claim 10, wherein the thickness of the first conductive layer is greater than the skin depth of the first conductive layer, the thickness of the dielectric layer is greater than the penetration depth of the dielectric layer, and the thickness of the second conductive layer is greater than the skin depth of the second conductive layer.

12. A nanoantenna comprising at least one duo Aloe vera cruces concentration antenna structure according to claim 1, wherein the nanoantenna is configured to absorb incident radiation, the incident radiation having a frequency f; An electromagnetic wave energy absorber that satisfies 25 THz<f≦800 THz.

13. the incident radiation is incident normally to the nanoantenna, the nanoantenna has an average absorption corresponding to the incident radiation, the average absorption is AA; 13. The electromagnetic wave energy absorber according to claim 12, wherein 84.5%≦AA is satisfied.

14. a first conductive layer that receives thermal radiation, a plurality of first metal units arranged around one another to form a first tapered hole; and a first conductive layer located within the first tapered hole and including a plurality of second metal units arranged around each other to form a second tapered hole; a dielectric layer connected to the first conductive layer; a second conductive layer connected to the dielectric layer, the dielectric layer being located between the first conductive layer and the second conductive layer; a contact electrode disposed through the dielectric layer and electrically connected between the first conductive layer and the second conductive layer; a coaxial cable electrically connected to the contact electrode and converting the thermal radiation into direct current according to the Seebeck effect; a thermoelectric energy harvester, wherein the first tapered hole has at least one first centerline passing through a center of the first tapered hole, and the second tapered hole has at least one second centerline passing through a center of the second tapered hole, and an angle between the at least one first centerline and the at least one second centerline is 45 degrees.

15. 15. The thermoelectric energy harvester of claim 14, wherein the number of the at least one first centerline is two and the number of the at least one second centerline is two, the first centerlines are perpendicular to each other, and the second centerlines are perpendicular to each other.

16. 16. The thermoelectric energy harvester of claim 15, wherein each of the first metal units includes a curved surface, the curved surfaces of two adjacent first metal units are connected to each other, and the curved surfaces of the first metal units form a plurality of peaks, two of the peaks being on one of the first center lines and another two of the peaks being on the other of the first center lines.

17. 16. The thermoelectric energy harvester of claim 15, wherein each of the second metal units includes an outer curved surface and an inner curved surface, the outer curved surface and the inner curved surface forming a leaf pattern, the inner curved surfaces of two adjacent second metal units are connected to each other, and the inner curved surfaces of the second metal units form a plurality of peaks, two of the peaks being on one of the second center lines and another two of the peaks being on the other of the second center lines.

18. 15. The thermoelectric energy harvester of claim 14, wherein the first conductive layer is made of a P-type semiconductor and the second conductive layer is made of an N-type semiconductor.

19. 15. The thermoelectric energy harvester of claim 14, wherein the first conductive layer is made of nickel or one of a plurality of P-type conductive materials, and the second conductive layer is made of gold or one of a plurality of N-type conductive materials.

20. 1. A photoconductive antenna configured to replace either a spiral antenna or a bowtie antenna, comprising: A first conductive layer of the duo aloe vera cruces concentration antenna structure of claim 1; a light-absorbing semiconductor layer connected to the first conductive layer, the structure of which is the same as that of the dielectric layer of the duo aloe vera cruces concentration antenna structure of claim 1; A photoconductive antenna comprising: a second conductive layer of the duo Aloe vera cruces concentration antenna structure of claim 1 connected to the light absorbing semiconductor layer, the second conductive layer being located between the first conductive layer and the second conductive layer.

21. 10. An array antenna comprising a plurality of duo aloe vera cruces concentration antenna structures according to claim 1, wherein the plurality of first conductive layers of the duo aloe vera cruces concentration antenna structure are spaced apart, the plurality of dielectric layers of the duo aloe vera cruces concentration antenna structure are spaced apart, and the plurality of second conductive layers of the duo aloe vera cruces concentration antenna structure are connected to each other or integrally formed.

22. 22. The array antenna of claim 21, wherein a slot having a width is arranged between each two of the first conductive layers, the plurality of slots are connected to each other in a lattice pattern, and the widths of the slots are all the same.

23. 1. A rectenna for use in a communication or energy harvesting device, comprising: The duo aloe vera cruces concentration antenna structure of claim 1 for receiving radio frequency signals or radiation; a rectifier module electrically connected to the duo aloe vera cruces concentration antenna structure and configured to convert the radio frequency signal or radiation from alternating current to direct current.

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