Ultra-wideband omnidirectional double-aloe concentric cross antenna structure

Abstract

The present disclosure provides a dual aloe concentric cross antenna structure including a first conductive layer, a dielectric layer, and a second conductive layer. A plurality of first metal units of the first conductive layer form a first taper hole. A plurality of second metal units of the first conductive layer are located in the first taper hole and form a second taper hole. A plurality of third metal units and a plurality of fourth metal units of the dielectric layer are respectively aligned with the plurality of first metal units and the plurality of second metal units. The second conductive layer is connected with the dielectric layer. The first taper hole is provided with at least one first center line, the second taper hole is provided with at least one second center line, and the included angle between the at least one first center line and the at least one second center line is 45 degrees.

Description

background Technical Field

[0002] The present disclosure relates to a double aloe concentric cross antenna structure, an electromagnetic wave energy absorber, a thermoelectric energy collector, a photoconductive antenna, an array antenna and a rectifier antenna, and in particular to an ultra-wideband omnidirectional polarization-insensitive double aloe concentric cross antenna structure applied to an electromagnetic wave energy absorber, a thermoelectric energy collector, a photoconductive antenna, an array antenna and a rectifier antenna. Background Art

[0003] Since modern society is highly dependent on battery sources for ultra-low power electronic devices, battery power is often the limiting factor, resulting in the tedious task of handling and replacing large numbers of batteries and causing environmental pollution. To address this issue, ambient electromagnetic (EM) energy harvesting provides a green, environmentally friendly and sustainable approach. To date, a variety of methods have been studied to harvest this free electromagnetic radiation energy. Some research teams have proposed and experimentally demonstrated mechanically flexible, polarization-independent and nearly uniform broadband absorbers. However, the broadband absorber structures in the prior art can only operate within a limited frequency band, limiting their practical applications.

[0004] The concept of capturing electromagnetic energy using antennas has been around for decades. This involves collecting ambient electromagnetic radiation and converting it into electrical energy to power low-power electronic devices. Energy harvesters can convert this ambient electromagnetic energy into usable electrical energy. Among all visible energy harvesting, the industry mainly uses photovoltaic (PV) and thermal solar cells for implementation. However, the performance of solar cells is affected by factors such as narrow-band absorption, bad weather, and visible light that only appears during daytime. Therefore, there is a great need for an alternative that can alleviate the aforementioned factors. In addition, traditional solar cells cannot collect most of the solar radiation that belongs to infrared wavelengths. In order to cope with the current crisis of insufficient renewable energy, it is very necessary to collect waste heat at infrared wavelengths and even longer wavelengths and convert them into usable energy.

[0005] In view of this, how to establish a perfect broadband absorber that can minimize reflection and transmission and maximize absorption bandwidth within a broadband range has indeed been highly anticipated by the public and has become a problem that relevant industry players are eager to solve. Summary of the invention

[0006] According to one embodiment of the present disclosure, a double aloe concentric cross antenna structure is provided, which 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 plurality of first metal units are arranged around each other to form a first conical hole. The plurality of second metal units are located in the first conical hole and are arranged around each other to form a second conical 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 plurality of third metal units are aligned with the plurality of first metal units respectively. The plurality of fourth metal units are aligned with the plurality of second metal units respectively. The second conductive layer is connected to the dielectric layer, wherein the dielectric layer is located between the first conductive layer and the second conductive layer. The first conical hole has at least one first center line passing through a center of the first conical hole, the second conical hole has at least one second center line passing through a center of the second conical hole, and an angle between the at least one first center line and the at least one second center line is 45 degrees.

[0007] According to another embodiment of the present disclosure, an electromagnetic wave energy absorber is provided, which includes a nano-antenna. The nano-antenna includes at least one of the aforementioned double aloe concentric cross antenna structures. The nano-antenna is used to absorb an incident radiation, the frequency of the incident radiation is f, and satisfies the following conditions: 25THz <f≤800THz。

[0008] According to another embodiment of the present disclosure, a thermoelectric energy collector is provided, which includes a first conductive layer, a dielectric layer, a second conductive layer, a contact electrode and a coaxial cable. The first conductive layer receives a thermal radiation and includes a plurality of first metal units and a plurality of second metal units. The plurality of first metal units are arranged around each other to form a first conical hole. The plurality of second metal units are located in the first conical hole and are arranged around each other to form a second conical hole. The dielectric layer is connected to the first conductive layer. The second conductive layer is connected to the dielectric layer, wherein the dielectric layer is located between the first conductive layer and the second conductive layer. The contact electrode is disposed in the dielectric layer and is electrically connected between the first conductive layer and the second conductive layer. The coaxial cable is electrically connected to the contact electrode and converts the thermal radiation into a direct current according to a Seebeck effect. The first conical hole has at least one first center line passing through a center of the first conical hole, the second conical hole has at least one second center line passing through a center of the second conical hole, and an angle between the at least one first center line and the at least one second center line is 45 degrees.

[0009] According to another embodiment of the present disclosure, a photoconductive antenna is provided, which is used to replace one of a spiral antenna and a bow tie antenna, and the photoconductive antenna includes the first conductive layer of the aforementioned double aloe concentric cross antenna structure, a light absorbing semiconductor layer, and the second conductive layer of the aforementioned double aloe concentric cross antenna structure. The light absorbing semiconductor layer is connected to the first conductive layer, wherein the structure of the light absorbing semiconductor layer is the same as the structure of the dielectric layer of the aforementioned double aloe concentric cross antenna structure. The second conductive layer is connected to the light absorbing semiconductor layer, wherein the light absorbing semiconductor layer is located between the first conductive layer and the second conductive layer.

[0010] According to another embodiment of the present disclosure, an array antenna is provided, which includes a plurality of the aforementioned dual-aloe concentric cross antenna structures. The plurality of first conductive layers of the plurality of dual-aloe concentric cross antenna structures are arranged at intervals from each other, the plurality of dielectric layers of the plurality of dual-aloe concentric cross antenna structures are arranged at intervals from each other, and the plurality of second conductive layers of the plurality of dual-aloe concentric cross antenna structures are connected to each other or formed as one piece.

[0011] According to another embodiment of the present disclosure, a rectifier antenna is provided, which is used in a communicator or an energy collection device, and the rectifier antenna includes the aforementioned double aloe concentric cross antenna structure and a rectifier module. The double aloe concentric cross antenna structure is used to receive a radio frequency signal or a radiation. The rectifier module is electrically connected to the double aloe concentric cross antenna structure and converts the radio frequency signal or radiation from an alternating current to a direct current. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure may be more fully understood by reading the following detailed description of the embodiments in conjunction with the accompanying drawings:

[0013] Figure 1A FIG. 3 is a three-dimensional schematic diagram of a double-aloe concentric cross antenna structure according to a first embodiment of the present disclosure.

[0014] Figure 1B Draw Figure 1A Schematic diagram of the decomposition of the double aloe concentric cross antenna structure.

[0015] Figure 1C Draw Figure 1A Top view of the dual-aloe concentric cross antenna structure.

[0016] Figure 2A Draw Figure 1A 3D schematic diagram of the first conductive layer of the dual-Aloe concentric cross antenna structure.

[0017] Figure 2B Draw Figure 2A Top view (in the xy plane) of the first conductive layer of the dual-aloe concentric cross antenna structure.

[0018] Figure 3 A schematic diagram of an electromagnetic wave energy absorber according to a second embodiment of the present disclosure is shown.

[0019] Figure 4 A schematic diagram of a thermoelectric energy harvester according to a third embodiment of the present disclosure is shown.

[0020] Figure 5 FIG. 4 is a schematic diagram of a photoconductive antenna according to a fourth embodiment of the present disclosure.

[0021] Figure 6 A two-dimensional schematic diagram of an array antenna according to a fifth embodiment of the present disclosure is shown.

[0022] Fig. 7A A graph showing the reflectivity, transmittance and absorptivity of the double-aloe concentric cross antenna structure of the present disclosure under normal incidence of a plane wave.

[0023] Figure 7B A graph showing the reflectivity, transmittance and absorptivity of the array antenna of the present disclosure under normal incidence of a plane wave.

[0024] Fig. 8A An impedance curve diagram of the double aloe concentric cross antenna structure of the present disclosure is shown.

[0025] Figure 8B An impedance curve diagram of the array antenna of the present disclosure is shown.

[0026] Fig.9A A top view of the electric field distribution of the double-aloe concentric cross antenna structure of the present disclosure is shown.

[0027] Fig. 9B A cross-sectional view showing the electric field distribution of the double-aloe concentric cross antenna structure of the present disclosure is shown.

[0028] Fig.10 The power flow curves of the double aloe concentric cross antenna structure of the present disclosure at different depths at 278.5 THz are shown.

[0029] Fig.11A FIG. 4 is an absorption spectrum diagram of the double-aloe concentric cross antenna structure of the present disclosure at different incident angles ranging from 0° to 75° in the transverse electric field mode.

[0030] Fig. 11B FIG. 4 is an absorption spectrum diagram of the double-aloe concentric cross antenna structure of the present disclosure at different incident angles ranging from 0° to 75° in the transverse magnetic field mode.

[0031] Fig. 11CFIG. 4 is an absorption spectrum diagram of the double-aloe concentric cross antenna structure of the present disclosure in the transverse electric field mode at different polarization angles ranging from 0° to 90°.

[0032] Fig.11D FIG. 4 is an absorption spectrum diagram of the double-aloe concentric cross antenna structure of the present disclosure at different polarization angles ranging from 0° to 90° in the transverse magnetic field mode.

[0033] Fig. 12A A three-dimensional schematic diagram of the far-field direction of the dual-aloe concentric cross antenna structure of the present disclosure at 278.5 THz is shown.

[0034] Fig. 12B A polar coordinate diagram of the far-field direction of the dual-aloe concentric cross antenna structure of the present disclosure at 278.5 THz is shown.

[0035] Fig.13A A three-dimensional schematic diagram showing the antenna gain of the dual-aloe concentric cross antenna structure of the present disclosure at 278.5 THz is shown.

[0036] Fig. 13B A polar coordinate diagram of the antenna gain of the dual-aloe concentric cross antenna structure of the present disclosure at 278.5 THz is shown.

[0037] Fig.14 A schematic diagram of a rectenna according to a sixth embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0038] The following will describe multiple embodiments of the present disclosure with reference to the accompanying drawings. For the sake of clarity, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present disclosure. That is, in some embodiments of the present disclosure, these practical details are not necessary. In addition, in order to simplify the drawings, some conventional structures and elements will be depicted in a simple schematic manner in the drawings; and repeated elements may be represented by the same number.

[0039] It should be understood that when an element (or device) is "connected" to another element, it may mean that the element is directly connected to the other element, or it may mean that the element is indirectly connected to the other element, that is, there are other elements between the element and the other element. On the contrary, when it is clearly stated that an element is "directly connected" to another element, it means that there are no other elements between the element and the other element. In addition, the terms first, second, third, etc. are only used to describe different elements, and do not limit the elements themselves. Therefore, the first element or component discussed below can be called the second element or component.

[0040] Please also read Figure 1A , Figure 1B and Figure 1C . Figure 1A FIG. 1 is a three-dimensional schematic diagram of a dual-aloe concentric cross antenna structure 100 according to a first embodiment of the present disclosure. Figure 1B Draw Figure 1A Schematic diagram of an exploded view of a dual-aloe concentric cross antenna structure 100. Figure 1C Draw Figure 1A A top view of the dual aloe concentric cross antenna structure 100. Figure 1A , Figure 1B and Figure 1C In the embodiment, the double-aloe concentric cross antenna structure 100 includes a first conductive layer 200 , a dielectric layer 300 and a second conductive layer 400 .

[0041] The first conductive layer 200 includes a plurality of first metal units 210 and a plurality of second metal units 220. The plurality of first metal units 210 are arranged around each other to form a first conical hole 230. The plurality of second metal units 220 are located in the first conical hole 230 and are arranged around each other to form a second conical hole 240.

[0042] 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 plurality of third metal units 310 are arranged around each other to form a third conical hole 330. The plurality of fourth metal units 320 are located in the third conical hole 330 and are arranged around each other to form a fourth conical hole 340. In addition, the plurality of third metal units 310 are respectively aligned with the plurality of first metal units 210. The plurality of fourth metal units 320 are respectively aligned with the plurality of second metal units 220.

[0043] The second conductive layer 400 is connected to the dielectric layer 300, and 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 plurality of first metal units 210 and each of the plurality of third metal units 310 are stacked and covered on the surface 401, and each of the plurality of second metal units 220 and each of the plurality of fourth metal units 320 are stacked and covered on 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.

[0044] It is worth noting that the first tapered hole 230 has at least one first center line CL passing through a center of the first tapered hole 230. 1 The second tapered hole 240 has at least one second center line CL passing through a center of the second tapered hole 240. 2The center of the first conical hole 230 is the same as the center of the second conical hole 240, and the same center is located in the middle of the first conductive layer 200. In detail, the at least one first center line CL 1 The number is two, and the at least one second center line CL 2 The number of the two first center lines CL is two. 1 perpendicular to each other, and the two second center lines CL 2 It is worth noting that the at least one first center line CL 1 and at least one second center line CL 2 The angle θ between them is 45 degrees. Similar to the first conductive layer 200, the third conical hole 330 in the dielectric layer 300 has at least one third center line (not shown) passing through a center of the third conical hole 330, and the fourth conical hole 340 in the dielectric layer 300 has at least one fourth center line (not shown) passing through a center of the fourth conical hole 340, and the angle between the at least one third center line and the at least one fourth center line is 45 degrees.

[0045] Specifically, the dual aloe concentric cross antenna structure 100 of the present disclosure can be applied to electromagnetic (EM) wave absorbers for electromagnetic energy collection. A perfect electromagnetic wave absorber is a device in which all incident radiation is effectively absorbed at the operating wavelength. Once the incident radiation is absorbed by the device, it is converted into ohmic heat or other forms of energy. Therefore, reflection, penetration, scattering and other conducted waves are not observed when passing through a perfect electromagnetic wave absorber. Generally speaking, existing absorbers are made of materials with high inherent losses, but the dual aloe concentric cross antenna structure 100 of the present disclosure can be mainly composed of precious metals.

[0046] In detail, the first conductive layer 200 is made of lossy metal nickel (Ni). The dielectric layer 300 is made of a high insulation material, which can be SU-8. The second conductive layer 400 is made of lossy metal gold (Au). The first conductive layer 200 and the dielectric layer 300 are patterned, but the second conductive layer 400 is not patterned, but remains a continuous layer to avoid the transmission of electromagnetic waves. The dielectric layer 300 is sandwiched between the first conductive layer 200 and the second conductive layer 400. The properties of the above materials are listed in Table 1, but the present disclosure is not limited thereto.

[0047] Table 1

[0048]

[0049] In addition, the thickness of the first conductive layer 200 is Z 1 , the thickness of the dielectric layer 300 is Z 2 , the thickness of the second conductive layer 400 is Z 3 , and meets the following conditions: Z1 =Z 3 ≤Z 2 The thickness Z of the first conductive layer 200 is 1 The thickness Z of the dielectric layer 300 is greater than the skin depth of the first conductive layer 200. 2 is greater than the penetration depth of the dielectric layer 300, and the thickness Z of the second conductive layer 400 is 3 is greater than the skin depth of the second conductive layer 400. In the first embodiment, the thickness Z of the first conductive layer 200 is 1 The thickness Z of the second conductive layer 400 3 The thickness Z of the dielectric layer 300 is 200 nm. 2 The length L and width W of the double aloe concentric cross antenna structure 100 are both 1000 nm, but the present disclosure is not limited thereto.

[0050] Please also read Figure 1C , Figure 2A and Figure 2B . Figure 2A Draw Figure 1A 3D schematic diagram of the first conductive layer 200 of the double-aloe concentric cross antenna structure 100. Figure 2B Draw Figure 2A A top view (in the xy plane) of the first conductive layer 200 of the double aloe concentric cross antenna structure 100. Figure 1C and Figure 2A As shown, the plurality of first metal units 210 include a plurality of curved surfaces 211. Two adjacent curved surfaces 211 of the plurality of first metal units 210 are connected to each other. The plurality of curved surfaces 211 of the plurality of first metal units 210 form four peaks 212, and two of the plurality of peaks 212 are located at two first center lines CL 1 and the other two of the plurality of peaks 212 are located on the second first center line CL 1 The other.

[0051] In addition, the plurality of second metal units 220 may include a plurality of outer curved surfaces 221 and a plurality of inner curved surfaces 222. Each of the plurality of outer curved surfaces 221 and each of the plurality of inner curved surfaces 222 form a leaf pattern on the surface of the first conductive layer 200. Two of the plurality of inner curved surfaces 222 of two adjacent second metal units 220 are connected to each other. The plurality of inner curved surfaces 222 of the plurality of second metal units 220 form four peaks 223, two of the plurality of peaks 223 are located at two second center lines CL 2 and the other two of the plurality of peaks 223 are located on the second center line CL 2The other.

[0052] Specifically, the structure of the first conductive layer 200 is conical, thereby generating four identical petals (i.e., the first metal units 210). The identical petals surround four identical leaf patterns (i.e., the second metal units 220) located at the center of the first conductive layer 200. The six spline curves in plan each of the multiple second metal units 220 close to the center of the first conductive layer 200, and the structure formed by the second metal unit 220 is rotated 90° relative to the structure formed by the first metal unit 210. The structure of the dielectric layer 300 is similar and will not be described in detail. Thereby, the conical structure of the double aloe concentric cross antenna structure 100 of the present disclosure can be combined with a nano-antenna to limit infrared (IR), the entire visible light and part of the ultraviolet-visible band. In addition, the double aloe concentric cross antenna structure 100 includes a metal-dielectric-metal (MDM) configuration, in which the first conductive layer 200 and the dielectric layer 300 are gradually tapered to produce a groove-shaped structure that can limit and cover wavelengths of different frequencies (such as Duo Aloe Vera crucesConcentricis in Latin). Due to the structural symmetry of the double aloe concentric cross antenna structure 100, polarization is not a factor in plane wave detection. The second metal unit 220 inside the first conductive layer 200 can cover a higher frequency region, while the first metal unit 210 outside the first conductive layer 200 can cover a lower frequency region to absorb electromagnetic waves. The double aloe concentric cross antenna structure 100 of the present disclosure will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0053] The tapered structure of the first conductive layer 200 is defined as an exponential curve in the xy plane, such as Figure 2B For each of the first metal units 210, the profile of the curved surface 211 may be an exponential cone. The exponential cone is composed of an aperture ratio R and two points P in the xy plane. 1 , P 2 Defined and satisfying the following equations (1), (2) and (3):

[0054] y=c 1 e Rx +c 2 (1);

[0055]

[0056]

[0057] In equations (1), (2) and (3), the aperture ratio R is represented by R, an x ​​coordinate of the xy plane is represented by x, a y coordinate of the xy plane is represented by y, and the point P is 1The x-coordinate of 1 , click P 1 The y coordinate of 1 , click P 2 The x-coordinate of 2 , click P 2 The y coordinate of 2 , the first variable value is represented by c 1 , and a second variable value is represented by c 2 .

[0058] like Figure 2B As shown, the taper length l is x 2 -x 1 For the profile of the curved surface 211, the aperture ratio R can vary between 0 and 0.7. In the limit case where the aperture ratio R approaches zero, the exponential taper produces a so-called linear progressive slot antenna, and its taper slope is constant. For example, the taper slope of the exponential taper is Denoted as S. The first cone slope of the exponential cone is at x=x 1 Indicated as S 1 , the slope of the second cone of the exponential cone is at x = x 2 Indicated as S 2 , when the cone angle of the exponential cone is represented by α, and the following equations (4), (5) and (6) are satisfied:

[0059]

[0060] S 1 <S<S 2 (5);

[0061] α=tan -1 S (6).

[0062] For the exponential cone defined by equation (1), the cone slope (i.e., S) changes from S 1 To S 2 Continuously changing, where S 1 and S 2 They are respectively at x=x 1 and x = x 2 The slope of the two cones in the case of R is greater than 0, S 1 <S<S 2 .

[0063] Similarly, the profile of the outer curved surface 221 and the inner curved surface 222 of each of the plurality of second metal units 220 may also be another exponential cone. This other exponential cone is formed by the aperture ratio R' and the two points P on the xy plane. 2 , P 2'Definition, and satisfy the following equations (7), (8) and (9):

[0064] y=c′ 1 e R′x +c′ 2 (7);

[0065]

[0066] In equations (7), (8) and (9), the aperture ratio R' is represented by R', an x ​​coordinate of the xy plane is represented by x, a y coordinate of the xy plane is represented by y, and the point P 2 The x-coordinate of 2 , click P 2 The y coordinate of 2 , click P 2 The x coordinate of ' is represented by x' 2 , click P 1 The y coordinate of 2 , a first variable value is denoted as c′ 1 , and a second variable value is denoted as c' 2 .

[0067] like Figure 2B As shown, the taper length l' is x' 2 -x 2 For the profile of the outer curved surface 221, the opening ratio R' can also vary between 0 and 0.7, just like the opening ratio R corresponding to the profile of the curved surface 211. The slope of a cone of this other exponential cone is This other exponential cone has a first cone slope at x=x 2 Denoted as S′ 1 The slope of a second cone of this other exponential cone is at x = x' 2 Denoted as S′ 2 , when a cone angle of the other exponential cone is represented by α′, and satisfies the following equations (10), (11) and (12):

[0068] S′ 1 <S′ 1 <S′ 2 (11);

[0069] α′=tan -1 S′ (12).

[0070] For this other exponential cone defined by equation (7), the cone slope (i.e., S′) changes from S′ to 1 to S′ 2 Continuously changing, where S′ 1and S′ 2 are the slopes of the two cones in the cases of x = x 2 and x = x′ 2 respectively, and when R' is greater than 0, S′ 1 <S′<S′ 2 . The parameters and dimensions of the first conductive layer 200 are listed in Table 2, but the present disclosure is not limited thereto.

[0071] Table 2

[0072] parameter size l 360nm l′ 140nm α 10.7° α′ 15.8° S 0.18 S′ 0.28

[0073] Please refer to Figure 3 . Figure 3 FIG. shows a schematic diagram of an electromagnetic wave energy absorber 500 according to a second embodiment of the present disclosure. The electromagnetic wave energy absorber 500 includes a nanoantenna 510. The nanoantenna 510 includes at least a pair of aloe concentric cross antenna structures 511. In the second embodiment, the number of at least a pair of aloe concentric cross antenna structures 511 can be multiple, and each of the pair of aloe concentric cross antenna structures 511 is the same as the pair of aloe concentric cross antenna structures 100 of the first embodiment. The nanoantenna 510 is used to absorb an incident radiation Ri, the frequency of the incident radiation Ri is f, and satisfies the following condition: 25 THz < f ≤ 800 THz. The incident radiation Ri is incident on the nanoantenna 510 along a normal direction, and the nanoantenna 510 has an average absorption rate corresponding to the incident radiation Ri. The average absorption rate is AA, and satisfies the following condition: 84.5% ≤ AA. Specifically, based on the pair of aloe concentric cross antenna structures 100, the nanoantenna 510 shows, after numerical analysis, that it is a promising candidate for energy harvesting applications in the range from infrared (IR) to ultraviolet (UV). The influence of the electromagnetic wave energy absorber 500 on the absorption performance has been tested and simulated, showing high performance in both the frequency bandwidth and the absorption rate (in the range from infrared to visible light, that is, from 25 THz to 800 THz, having an average absorption rate of 83.4% to 84.5%, as shown in Fig. 7A and Figure 7B below). In other embodiments, the pair of aloe concentric cross antenna structures 511 can also be used in energy harvesting devices using antennas. For example, broadband energy harvesting combined with an antenna can directly collect radio frequency energy through rectifiers, thermoelectrics, bolometers, pyroelectrics or quantum detectors, such as InGaAs and photoconductive materials, and convert it into direct current.

[0074] Please refer to Figure 4 . Figure 4A schematic diagram of a thermoelectric energy harvester 600 according to a third embodiment of the present disclosure is shown. 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 of the corresponding elements of the double aloe concentric cross antenna structure 100 of the first embodiment, so it is not repeated. However, the sizes of the first conductive layer 610, the dielectric layer 620, and the second conductive layer 630 can be the same as or different from the corresponding elements of the double aloe concentric cross antenna structure 100 of the first embodiment.

[0075] It should be noted that Figure 4 The dielectric layer 620 in FIG. 6 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 a direct current DC according to a Seebeck effect (electron diffusion caused by the thermal radiation Rh), and the direct current DC can be transmitted to the load R L And for the load R L Provide power.

[0076] Thermoelectric energy harvester 600 can be a portable or wearable thermoelectric generator that uses flexible conductive thermoelectric materials and ultra-wideband antennas as the heat receiving end of a thermoelectric (TE) module, thereby capturing ambient energy. A thermoelectric module is basically a circuit consisting of two different thermoelectric materials that can directly use thermal energy to generate electricity when combined together. The thermoelectric module consists of two different thermoelectric materials connected at both ends. One end is made of an N-type (electron-rich) semiconductor and the other end is made of a P-type (electron-poor) semiconductor. In detail, the first conductive layer 610 is composed of a P-type semiconductor and the second conductive layer 630 is composed of an N-type semiconductor. Specifically, the P-type semiconductor of the first conductive layer 610 is composed of nickel or one of a plurality of P-type conductive materials, and the N-type semiconductor of the second conductive layer is composed of gold or one of a plurality of N-type conductive materials. The first conductive layer 610 uses two concentric conical cross structures as the heat receiving end of the thermoelectric energy harvester 600 to improve energy absorption and frequency range.

[0077] See also Figure 5 . Figure 5A schematic diagram of a photoconductive antenna 700 according to a fourth embodiment of the present disclosure is shown. The photoconductive antenna 700 includes a first conductive layer 710, a light absorbing semiconductor layer 720, and a second conductive layer 730, and is used to replace one of a helical antenna (not shown separately) and a bow tie antenna (not shown separately). The first conductive layer 710 is the same as the first conductive layer 200 of the double aloe concentric cross antenna structure 100 of the first embodiment. The light absorbing semiconductor layer 720 is connected to the first conductive layer 710, and the structure of the light absorbing semiconductor layer 720 is the same as the structure of the dielectric layer 300 of the double aloe concentric cross antenna structure 100 of the first embodiment. The second conductive layer 730 is connected to the light absorbing semiconductor layer 720, and the structure of the second conductive layer 730 is the same as the structure of the second conductive layer 400 of the double aloe concentric cross 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. In short, 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 double aloe concentric cross antenna structure 100 of the first embodiment, so the detailed structure is not further described. Figure 5 As shown, the photoconductive antenna 700 receives a laser pulse Lp, and the laser pulse Lp excites the carriers accelerated by the potential +V, and the resulting charge separation leads to dipole emission at the terahertz frequency. In detail, the photoconductive antenna 700 basically utilizes the photoelectric effect to generate electrical energy and transmit and receive radiation (usually in the terahertz region). The photoconductive antenna 700 is composed of a metal antenna (i.e., a first conductive layer 710 and a light absorbing semiconductor layer 720) patterned on a photoconductive substrate (i.e., a second conductive layer 730). In the fourth embodiment, the photoconductive antenna 700 is not used as an energy harvesting device, but as a transceiver system.

[0078] Please also read Figure 1A and Figure 6 . Figure 6A two-dimensional schematic diagram of an array antenna 800 according to a fifth embodiment of the present disclosure is shown. The array antenna 800 includes a plurality of dual aloe concentric cross antenna structures 100 of the first embodiment. Specifically, the array antenna 800 is composed of a 3×3 array of dual aloe concentric cross antenna structures 100 of the first embodiment; in other words, the dual aloe concentric cross antenna structure 100 is a unit antenna structure of the array antenna 800. In the structure of the array antenna 800, the plurality of first conductive layers 200 of the plurality of dual aloe concentric cross antenna structures 100 are arranged at intervals from each other, and the plurality of dielectric layers 300 of the plurality of dual aloe concentric cross antenna structures 100 are arranged at intervals from each other. The plurality of second conductive layers 400 of the plurality of dual aloe concentric cross antenna structures 100 are connected to each other or formed integrally. There is a slot 810 between each two of the plurality of first conductive layers 200 and has a width 811, and the plurality of slots 810 are connected to each other to present a lattice shape. The plurality of slots 810 have the same width 811, and the width 811 of the plurality of slots 810 is 100 nm. In other embodiments, the plurality of first conductive layers of the plurality of dual-aloe concentric cross antenna structures can be connected in series, and the plurality of dielectric layers of the plurality of dual-aloe concentric cross antenna structures can be connected in series, so as to increase the voltage output; or, the plurality of first conductive layers of the plurality of dual-aloe concentric cross antenna structures can be connected in parallel, and the plurality of dielectric layers of the plurality of dual-aloe concentric cross antenna structures can be connected in parallel, so as to increase the output current.

[0079] The characteristics of the dual aloe concentric cross antenna structure 100 and the array antenna 800 will be tested below, and the results will be discussed.

[0080] <Reflectivity, transmittance, and absorptivity testing>

[0081] To reveal the physical origin of ultra-wideband (UWB) absorption, the dual aloe concentric cross antenna structure 100 and the array antenna 800 were tested under normal incidence to obtain reflectivity, penetration and absorption. Fig. 7A and Figure 7B . Fig. 7A A graph showing the reflectivity, transmittance and absorptivity of the double-aloe concentric cross antenna structure 100 of the present disclosure under normal incidence of a plane wave. Figure 7B A graph showing the reflectivity, transmittance and absorptivity of the array antenna 800 of the present disclosure under normal incidence of a plane wave. Fig. 7A and Figure 7BAs shown, the double aloe concentric cross antenna structure 100 has an excellent absorption bandwidth with an absorption rate of 84.5%, from 25THz to 800THz up to 775THz. The absorption performance of the array antenna 800 is not much different from that of the double aloe concentric cross antenna structure 100, and follows a trend that is almost similar to that of the double aloe concentric cross antenna structure 100. The array antenna 800 can obtain an average absorption rate of 83.4% within the working frequency band.

[0082] The effects of ultra-wideband and high absorption are derived from the mutual coupling and overlap between the continuous resonances in the dual aloe concentric cross antenna structure 100. The interaction between the incident wave and the tapered structure of the dual aloe concentric cross antenna structure 100 causes the antenna to consume more energy. In this case, most of the reflected waves are destructively coherent with each other within the operating frequency range, so the amount of incident waves reflected back from the surface is small, resulting in broadband absorption.

[0083] <Impedance Test>

[0084] Please also read Fig. 8A and Figure 8B . Fig. 8A FIG. 1 is an impedance curve diagram of the dual-aloe concentric cross antenna structure 100 of the present disclosure. Figure 8B The impedance curve of the array antenna 800 of the present disclosure is shown. Fig. 8A and Figure 8B In the embodiment, the closer the relative impedance of the absorber (i.e., the dual aloe concentric cross antenna structure 100 and the array antenna 800) matches the free space, the higher the absorption rate of the absorber. In general, the mechanism of broadband and high absorption of radio frequency (RF) is very simple. At RF, metal behaves like a perfect conductor, and the skin depth is negligible compared to the size of the antenna.

[0085] When the incident wave propagates as a plane wave on the conical structure of the double aloe concentric cross antenna structure 100, it will be reflected or absorbed, depending on the mismatch between the impedance of the conical structure and the impedance of free space. The strong impedance matching between the array antenna 800 and the surrounding free space is the reason for achieving this broadband characteristic. The second conductive layer 400 of the double aloe concentric cross antenna structure 100 is larger than the skin depth in the operating frequency range, resulting in negligible transmission (close to zero) and high absorption rate.

[0086] <Electric field distribution test>

[0087] In order to understand the basic physical principle behind ultra-wideband absorption, the electric field distribution of the double aloe concentric cross antenna structure 100 is studied. Fig.9A and Fig. 9B . Fig.9A FIG. 1 is a top view showing the electric field distribution of the dual-aloe concentric cross antenna structure 100 of the present disclosure. Fig. 9BA cross-sectional view showing the electric field distribution of the dual aloe concentric cross antenna structure 100 of the present disclosure is shown. Fig.9A and Fig. 9B In the figure, a specific frequency of 278.5 THz is selected to observe the top view on the xy plane (at z=0.9 μm) and the cross-sectional view on the yz plane (at x=0.141 μm) in the electric field distribution. It is observed that most of the electric field is confined to the surfaces of the first metal unit 210 and the second metal unit 220. The electric field on the surface of the first metal unit 210 and the second metal unit 220 is strong, which means that there is mutual influence between the two adjacent first metal units 210 and between the two adjacent second metal units 220. It can also be seen that when the electromagnetic wave propagates in the double aloe concentric cross antenna structure 100, the electric field is significantly reduced, and when it reaches the second conductive layer 400 at the bottom (not shown separately) Fig. 9B Therefore, the ultra-wideband absorption of the double aloe concentric cross antenna structure 100 shows that the continuous electrical resonance of the metal phase Ni is generated at multiple frequency points (from 170 THz to 800 THz), thereby generating effective ultra-wideband absorption within the operating frequency range.

[0088] <Power flow test>

[0089] See also Fig.10 . Fig.10 The power flow curves of the double aloe concentric cross antenna structure 100 of the present disclosure at different depths at 278.5 THz are shown. Fig.10 In the test, the excitation power used was 1.0 watt. Obviously, the first conductive layer 200 absorbs a large amount of power (0.8 watt on the surface), while the dielectric layer 300 and the second conductive layer 400 absorb very small amounts of power. The absorption of the double aloe concentric cross antenna structure 100 is mainly attributed to the ohmic loss or resistive loss of the first conductive layer 200. Most of the absorption occurs on the first conductive layer 200 and can be converted into a temperature rise of the top metal film of the first conductive layer 200.

[0090] <Testing of Transverse Electric (TE) Mode and Transverse Magnetic (TM) Mode>

[0091] For practical applications, polarization insensitivity and wide-angle incident waves are critical because in some cases the incident waves are incident obliquely to the device. Therefore, the polarization insensitivity of the dual-aloe concentric cross antenna structure 100 is tested for normal incidence and oblique incidence. Fig.11A , Fig. 11B , Fig. 11C and Fig.11D . Fig.11A FIG. 1 shows the absorption spectra of the double-aloe concentric cross antenna structure 100 of the present disclosure at different incident angles θ ranging from 0° to 75° in the transverse electric field mode. Fig. 11B FIG. 1 shows the absorption spectra of the double-aloe concentric cross antenna structure 100 of the present disclosure at different incident angles θ ranging from 0° to 75° in the transverse magnetic field mode. Fig. 11C FIG. 1 shows the absorption spectra of the double-aloe concentric cross antenna structure 100 of the present disclosure at different polarization angles φ ranging from 0° to 90° in the transverse electric field mode.

[0092] Fig.11D FIG. 1 shows absorption spectra of the double-aloe concentric cross antenna structure 100 of the present disclosure at different polarization angles φ ranging from 0° to 90° in a transverse magnetic field mode.

[0093] At Fig.11A and Fig. 11B In the figure, it can be seen that the absorption performance of the double aloe concentric cross antenna structure 100 does not change significantly within the operating frequency range. Under the oblique incidence of the incident wave at 45°, the average absorption rate of the TE mode remains above 82.7%, and the average absorption rate of the TM mode remains above 83.5%. Therefore, for the TE and TM modes, the double aloe concentric cross antenna structure 100 of the present disclosure has 45° polarization insensitivity. The unique mechanism of coupling between the relevant electric resonance and magnetic resonance and the incident light in free space is attributed to the angle-independent absorption.

[0094] At Fig. 11C and Fig.11D It is obvious that the average absorptivity does not change under the normal incidence of the plane wave at 90°, the average absorptivity of the TE mode remains above 83.91%, and the average absorptivity of the TM mode remains above 83.92%. This result is attributed to the fact that the dual aloe concentric cross antenna structure 100 is insensitive to the polarization of the TE and TM modes under the normal incidence of the incident wave at 90°. From the above findings, it can be concluded that at φ=90°, the TE mode becomes the TM mode, and vice versa. The polarization-insensitive nature of the dual aloe concentric cross antenna structure 100 is mainly due to the symmetrical arrangement of the conical structure between the first metal unit 210 and the second metal unit 220. Based on the above numerical results, it is obvious that the dual aloe concentric cross antenna structure 100 of the present disclosure is polarization-independent under both the normal and oblique incidence of the plane wave, and maintains the absorption performance for the TE and TM modes within the operating frequency band.

[0095] <Far field direction and gain test>

[0096] Please also read Fig. 12A , Fig. 12B , Fig.13A and Fig. 13B . Fig. 12A FIG. 3 is a three-dimensional schematic diagram showing the far-field direction of the dual-aloe concentric cross antenna structure 100 of the present disclosure at 278.5 THz.

[0097] Fig. 12B A polar coordinate diagram of the far field direction of the dual-aloe concentric cross antenna structure 100 of the present disclosure at 278.5 THz is shown. Fig.13A FIG. 3 is a three-dimensional schematic diagram showing the antenna gain of the dual-aloe concentric cross antenna structure 100 of the present disclosure at 278.5 THz. Fig. 13B A polar coordinate diagram showing the antenna gain of the dual aloe concentric cross antenna structure 100 of the present disclosure at 278.5 THz is shown. Fig. 12A and Fig. 12B , the numerical results obtained highlight that the maximum directivity value of the radiation pattern is 6.01dBi. The half-power beamwidth (HPBW) or 3dB bandwidth of the dual aloe concentric cross antenna structure 100 at 278.5THz is 209.8°, which is large enough to confirm that the dual aloe concentric cross antenna structure 100 is omnidirectional. The high directivity and beamwidth of the dual aloe concentric cross antenna structure 100 at 278.5THz are attributed to the symmetrical petal geometry. In addition, there are no nulls and lobes on the pattern, thereby forming an omnidirectional radiation pattern. Therefore, the absence of lobes and nulls on the pattern of the first conductive layer 200 maximizes the directivity, giving the dual aloe concentric cross antenna structure 100 better performance.

[0098] The gain of the dual aloe concentric cross antenna structure 100 is a measure of the maximum effective power, which represents the power that the dual aloe concentric cross antenna structure 100 can radiate from an external power or radiation source, or absorb the power received from an external power or radiation source. Specifically, it is defined as the maximum radiation intensity generated or absorbed by the dual aloe concentric cross antenna structure 100 compared to the radiation intensity provided or received by a lossless isotropic antenna. Fig.13A and Fig. 13B The dual aloe concentric cross antenna structure 100 of the present disclosure provides an optimal gain of 0.464 dB and a bandwidth of 209.8° wider than 3 dB. The gain of 0.464 dB means that the effective power received by the dual aloe concentric cross antenna structure 100 is 1.112 times the effective power received by the isotropic antenna.

[0099] See also Fig.14 . Fig.14A schematic diagram of a rectenna 900 according to a sixth embodiment of the present disclosure is shown. The rectenna 900 can be used in a communicator or an energy harvesting device, and includes a dual aloe concentric cross antenna structure 910 and a rectifier module 920. The dual aloe concentric cross antenna structure 910 can 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 of the corresponding elements of the dual aloe concentric cross antenna structure 100 of the first embodiment, so it will not be repeated.

[0100] The first conductive layer 911 of the dual aloe concentric cross antenna structure 910 is used to receive a radio frequency signal Rf or a radiation (not shown). The rectifier module 920 is electrically connected to the second conductive layer 913 of the dual aloe concentric cross antenna structure 910, and converts the radio frequency signal Rf or the radiation from an alternating current AC into a direct current DC, and the direct current DC can be transmitted to the load R L And for the load R L Specifically, when the rectenna 900 receives the radio frequency signal Rf, the rectenna 900 can be used as a communicator. When the rectenna 900 receives radiation, the rectenna 900 can be used as an energy collection device. It is worth noting that the rectenna 900 of the sixth embodiment is similar to Figure 4 The thermoelectric energy harvester 600 is a completely different energy harvesting device. Fig.14 In the embodiment, by connecting the double aloe concentric cross antenna structure 910 to the rectifier module 920, the radio frequency signal Rf can be converted from alternating current AC to direct current DC. Figure 4 In the embodiment of the present invention, the thermoelectric energy harvester 600 can absorb a radio frequency radiation (not shown) and convert it into direct current using rectification.

[0101] In summary, the present disclosure has the following advantages: First, the dual aloe concentric cross antenna structure has excellent absorption bandwidth, and the absorption rate from 25 to 800 THz under normal incidence is as high as 775 THz, reaching 84.5%. Second, for TE and TM modes, the dual aloe concentric cross antenna structure produces an absorption deviation of less than 5% between the normal and 45° incident angles, and an absorption deviation of less than 0.05% between 0° and 90° polarization. Third, the dual aloe concentric cross antenna structure is omnidirectional because the half-power beamwidth or 3dB bandwidth is 209.8° at 278.5 THz.

[0102] Although the present disclosure has been disclosed above in terms of embodiments, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained therein.

[0103] Anyone skilled in the art may make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the appended claims.

Claims

1. A double aloe concentric cross antenna structure, comprising: A first conductive layer comprising: A plurality of first metal units are arranged around each other to form a first tapered hole; and A plurality of second metal units are located in the first tapered hole and are arranged around each other to form a second tapered hole; a dielectric layer connected to the first conductive layer and comprising: a plurality of third metal units, respectively aligned with the plurality of first metal units; and a plurality of fourth metal units, respectively aligned with the plurality of second metal units; as well as a second conductive layer connected to the dielectric layer, wherein 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 a center of the first tapered hole, the second tapered hole has at least one second center line passing through a center of the second tapered hole, and an angle between the at least one first center line and the at least one second center line is 45 degrees.

2. The double aloe concentric cross antenna structure as described in 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 two first center lines are perpendicular to each other, and the two second center lines are perpendicular to each other.

3. The double aloe concentric cross antenna structure as described in claim 2, wherein the plurality of first metal units include a plurality of curved surfaces, two of the plurality of curved surfaces of two adjacent ones of the plurality of first metal units are connected to each other, the plurality of curved surfaces of the plurality of first metal units form a plurality of peaks, two of the plurality of peaks are located on one of the two first center lines, and the other two of the plurality of peaks are located on the other of the two first center lines.

4. The double aloe concentric cross antenna structure as claimed in claim 3, wherein the profile of each of the plurality of curved surfaces is an exponential cone, the exponential cone is defined by an aperture ratio and two points in an xy plane, and satisfies the following equations: and=c1e Rx +c2; in, The aperture ratio is represented as R and varies from 0 to 0.7, an x-coordinate of the xy plane is represented as x, a y-coordinate of the xy plane is represented as y, an x-coordinate of one of the two points is represented as x1, a y-coordinate of the one of the two points is represented as y1, an x-coordinate of the other of the two points is represented as x2, a y-coordinate of the other of the two points is represented as y2, a first variable value is represented as c1, and a second variable value is represented as c2.

5. The double aloe concentric cross antenna structure as claimed in claim 4, wherein a cone slope of the exponential cone is When denoted as S, a first cone slope of the exponential cone at x=x1 is denoted as S1, a second cone slope of the exponential cone at x=x2 is denoted as S2, and a cone opening angle of the exponential cone is denoted as α, the following multiple equations are satisfied: S1<S<S2; α=tan -1 S.

6. The double aloe concentric cross antenna structure as described in claim 2, wherein the plurality of second metal units include a plurality of outer curved surfaces and a plurality of inner curved surfaces, each of the plurality of outer curved surfaces and each of the plurality of inner curved surfaces form a leaf pattern, two of the plurality of inner curved surfaces of two adjacent ones of the plurality of second metal units are connected to each other, the plurality of inner curved surfaces of the plurality of second metal units form a plurality of peaks, two of the plurality of peaks are located on one of the two second center lines, and the other two of the plurality of peaks are located on the other of the two second center lines.

7. The double aloe concentric cross antenna structure as described in claim 2, wherein the plurality of third metal units are arranged around each other to form a third tapered hole, the plurality of fourth metal units are located in the third tapered hole and are arranged around each other to form a fourth tapered hole, the third tapered hole has at least one third center line passing through a center of the third tapered hole, the fourth tapered hole has at least one fourth center line passing through a center of the fourth tapered hole, and an angle between the at least one third center line and the at least one fourth center line is 45 degrees.

8. The double aloe concentric cross antenna structure as described in claim 1, wherein the second conductive layer comprises a surface, one of the plurality of first metal units and one of the plurality of third metal units are stacked and covered on the surface, and one of the plurality of second metal units and one of the plurality of fourth metal units are stacked and covered on the surface. 9 . The double-aloe concentric cross antenna structure as claimed in claim 1 , wherein the dielectric layer is made of a high-insulation material, and the high-insulation material is SU-8.

10. The double aloe concentric cross antenna structure as claimed in claim 1, wherein a thickness of the first conductive layer is Z1, a thickness of the dielectric layer is Z2, a thickness of the second conductive layer is Z3, and the following conditions are met: Z1=Z3≤Z2.

11. The double aloe concentric cross antenna structure as claimed in claim 10, wherein the thickness of the first conductive layer is greater than a skin depth of the first conductive layer, the thickness of the dielectric layer is greater than a penetration depth of the dielectric layer, and the thickness of the second conductive layer is greater than a skin depth of the second conductive layer.

12. An electromagnetic wave energy absorber, comprising: A nano-antenna, comprising at least one double aloe concentric cross antenna structure as claimed in claim 1, wherein the nano-antenna is used to absorb an incident radiation, the incident radiation has a frequency of f, and satisfies the following conditions: 25THz <f≤800THz。 13. The electromagnetic wave energy absorber as claimed in claim 12, wherein the incident radiation enters the nano-antenna along a normal direction, and the nano-antenna has an average absorptivity corresponding to the incident radiation, the average absorptivity is AA, and meets the following conditions: 84.5%≤AA.

14. A thermoelectric energy harvester comprising: A first conductive layer receives thermal radiation and comprises: A plurality of first metal units are arranged around each other to form a first tapered hole; and A plurality of second metal units are located in the first tapered hole and are 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, wherein the dielectric layer is located between the first conductive layer and the second conductive layer; a contact electrode, which penetrates the dielectric layer and is electrically connected between the first conductive layer and the second conductive layer; and a coaxial cable electrically connected to the contact electrode and converting the thermal radiation into a DC current according to a Seebeck effect; in, The first tapered hole has at least one first center line passing through a center of the first tapered hole, the second tapered hole has at least one second center line passing through a center of the second tapered hole, and an angle between the at least one first center line and the at least one second center line is 45 degrees. 15 . The thermoelectric energy harvester as claimed in claim 14 , 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 two first center lines are perpendicular to each other, and the two second center lines are perpendicular to each other.

16. A thermoelectric energy collector as described in claim 15, wherein the multiple first metal units include multiple curved surfaces, two of the multiple curved surfaces of two adjacent ones of the multiple first metal units are connected to each other, the multiple curved surfaces of the multiple first metal units form a multiple peaks, two of the multiple peaks are located on one of the two first center lines, and the other two of the multiple peaks are located on the other of the two first center lines.

17. A thermoelectric energy collector as described in claim 15, wherein the plurality of second metal units include a plurality of outer curved surfaces and a plurality of inner curved surfaces, each of the plurality of outer curved surfaces and each of the plurality of inner curved surfaces form a leaf pattern, two of the plurality of inner curved surfaces of two adjacent ones of the plurality of second metal units are interconnected, the plurality of inner curved surfaces of the plurality of second metal units form a plurality of peaks, two of the plurality of peaks are located on one of the two second center lines, and the other two of the plurality of peaks are located on the other of the two second center lines. 18 . 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. 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. A photoconductive antenna for replacing one of a helical antenna and a bow tie antenna, the photoconductive antenna comprising: The first conductive layer of the double aloe concentric cross antenna structure as claimed in claim 1; a light absorbing semiconductor layer connected to the first conductive layer, wherein the structure of the light absorbing semiconductor layer is the same as the structure of the dielectric layer of the double aloe concentric cross antenna structure; and The second conductive layer of the double-aloe concentric cross antenna structure is connected to the light absorbing semiconductor layer, wherein the light absorbing semiconductor layer is located between the first conductive layer and the second conductive layer.

21. An array antenna, comprising: A plurality of dual aloe concentric cross antenna structures as described in claim 1, wherein the plurality of first conductive layers of the plurality of dual aloe concentric cross antenna structures are arranged at intervals with each other, the plurality of dielectric layers of the plurality of dual aloe concentric cross antenna structures are arranged at intervals with each other, and the plurality of second conductive layers of the plurality of dual aloe concentric cross antenna structures are connected to each other or formed as one piece.

22. The array antenna as claimed in claim 21, wherein a slot having a width is provided between each two of the plurality of first conductive layers, the plurality of slots of the plurality of first conductive layers are interconnected to present a lattice shape, and the plurality of slots have the same width.

23. A rectenna for use in a communicator or an energy collection device, wherein the rectenna comprises: The double aloe concentric cross antenna structure as claimed in claim 1, used to receive a radio frequency signal or a radiation; and A rectifier module is electrically connected to the double aloe concentric cross antenna structure and converts the radio frequency signal or the radiation from an alternating current into a direct current.

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