Microwave rectification antenna

Abstract

The utility model relates to a microwave rectification antenna comprising an integrated antenna-rectification unit, a reconfigurable frequency selection module, a heat radiation layer and a protection cover. The integrated antenna-rectification unit comprises an antenna radiation layer and a rectification module which are fixedly connected; the antenna radiation layer is a butterfly-shaped metal patch, and the center of the butterfly-shaped metal patch is provided with a feeding point. The rectification module comprises a dielectric substrate and a grounding layer which are arranged in sequence; the grounding layer is connected with the antenna radiation layer through a metalized via hole array, and a plurality of via holes are annularly distributed at the edge of the antenna radiation layer. The microwave rectification antenna is ingenious in design, the antenna and the rectification unit are integrated together, better impedance matching can be achieved, energy loss caused by separation type design is reduced, and therefore the conversion efficiency is improved, and the size is small and exquisite.

Description

Technical Field

[0001] This utility model relates to the field of antenna technology, and in particular to a microwave rectifier antenna. Background Technology

[0002] Microwave rectifier antennas are core components of wireless power transmission systems, consisting of a receiving antenna and a rectifier circuit, used to convert microwave energy in space into DC power. Existing microwave rectifier antennas suffer from the following problems:

[0003] 1. Low conversion efficiency: Traditional rectifier antennas use a separate design (the antenna and rectifier circuit are separate), which results in poor impedance matching and energy loss.

[0004] 2. Narrow bandwidth: Antenna designs with a single resonant frequency cannot adapt to microwave sources with multiple frequency bands or dynamic frequencies.

[0005] 3. Size and cost limitations: Separate components result in large device size and high manufacturing cost, making it difficult to integrate into small devices. Utility Model Content

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a microwave rectifier antenna that can effectively solve the aforementioned problems.

[0007] To achieve the above requirements, the technical solution adopted by this utility model to solve its technical problem is as follows:

[0008] This invention provides a microwave rectifier antenna, comprising an integrated antenna-rectifier unit, a reconfigurable frequency selection module, a heat dissipation layer, and a protective cover. The integrated antenna-rectifier unit includes a fixedly connected antenna radiating layer and a rectifier module. The antenna radiating layer is a butterfly-shaped metal patch with etched slots on its surface, and a feed point electrically connected to the rectifier module is located at the center of the butterfly-shaped metal patch. The rectifier module includes a dielectric substrate and a ground layer arranged sequentially. The ground layer is connected to the antenna radiating layer through a metallized via array, with multiple vias distributed in a ring around the edge of the antenna radiating layer. The reconfigurable frequency selection module is disposed above the antenna radiating layer and is composed of periodic cross-shaped metal units, with a microwave rectifier element for detection or rectification circuitry embedded in its center. The heat dissipation layer is attached to the bottom of the ground layer, and its surface is etched with microgrooves for heat dissipation. The protective cover covers the reconfigurable frequency selection module and its surface is coated with a hydrophobic coating.

[0009] The microwave rectifier antenna of this utility model has a butterfly-shaped metal patch with a wingspan angle of 60°, a single wing length of 15 mm and a width of 10 mm, and the slot size of 1.5 mm × 0.5 mm with a spacing of 2 mm, arranged radially.

[0010] The microwave rectifier antenna of this invention has a Schottky diode welded to the feed point of the antenna radiating layer. The anode of the diode is connected to the butterfly-shaped metal patch through a microstrip line, and the cathode is connected to the ground layer through a via.

[0011] The microwave rectifier antenna of this utility model has a cross-shaped metal unit arm with a length of 7.5 mm, an arm width of 0.5 mm, and a unit period of 15 mm. The microwave rectifier element used for the detection or rectification circuit is model BAR50-02V and is connected to an external controller via a flexible circuit board.

[0012] The microwave rectifier antenna of this utility model has a heat dissipation layer made of aluminum nitride ceramic substrate with a thickness of 0.5 mm, a micro-groove depth of 0.2 mm and a spacing of 1 mm, and is attached to the ground layer and the back of the diode by thermally conductive silicone grease.

[0013] The microwave rectifier antenna of this utility model has a protective cover made of a transparent polyimide film with a thickness of 0.05 mm and a transmittance of >95%, and the edges are sealed with epoxy resin.

[0014] The microwave rectifier antenna of this utility model further includes a DC-DC converter and an output interface;

[0015] The DC-DC converter, model LT8610, is mounted on the outside of the heat dissipation layer, with an input voltage of 1.8-5.5 V and an output of 5V / 200 mA.

[0016] The output interface is a Micro-USB or a gold-plated test pad, soldered to the output end of the DC-DC converter.

[0017] The microwave rectifier antenna of this utility model has a dielectric substrate made of FR4 material, with dimensions of 30 mm × 30 mm × 0.8 mm, a dielectric constant of 4.4, and a loss tangent of 0.02.

[0018] This microwave rectifier antenna is ingeniously designed and has the following beneficial effects:

[0019] 1. By integrating the antenna and rectifier unit together, better impedance matching can be achieved, reducing energy loss caused by the separate design and thus improving conversion efficiency;

[0020] 2. The combination of periodic cross-shaped metal units and microwave rectifier elements for detection or rectification circuits allows the antenna to operate at different frequencies, enabling dynamic adjustment of the frequency band. By changing the conduction state of the microwave rectifier elements for detection or rectification circuits, it can adapt to microwave sources with multiple frequency bands or dynamic frequencies, broaden the operating frequency band, solve the problem of a single resonant frequency, and enable the antenna to adapt to microwave sources with multiple frequency bands or dynamic frequencies.

[0021] 3. By setting the metal patch of the antenna radiating layer into a butterfly shape, multiple resonant modes can be excited, covering a wider frequency range. The butterfly patch structure can guide the current to be evenly distributed along the edge of the patch, reducing the current congestion effect and reducing ohmic loss. Compared with the circular or rectangular patches in the prior art, the current path of the butterfly structure is longer and smoother, which is beneficial to improving radiation efficiency.

[0022] 4. The micro-groove design of the heat dissipation layer helps to improve heat dissipation efficiency and prevent the rectifier circuit from degrading due to temperature rise; and effective heat dissipation can ensure the stability and reliability of the rectifier antenna during long-term operation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the utility model will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of the microwave rectifier antenna of this utility model.

[0025] Figure 2 yes Figure 1 Exploded view of the microwave rectifier antenna in the image.

[0026] Figure 3 yes Figure 1 A comparison table of butterfly-shaped patches and rectangular patches in existing technologies. Detailed Implementation

[0027] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] "Multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0030] Furthermore, the terms indicating orientation, such as "up," "down," "left," "right," "upper end," "lower end," and "longitudinal," are all based on the posture and position of the device or equipment described in this solution during normal use.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of this utility model. Obviously, the described embodiments are some, but not all, embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0032] A preferred embodiment of the present invention provides a microwave rectifier antenna 100, such as... Figure 1-3 As shown, it includes an integrated antenna-rectifier unit 10, a reconfigurable frequency selection module 20, a heat dissipation layer 30, and a protective cover 40.

[0033] The integrated antenna-rectifier unit 10 includes a fixedly connected antenna radiating layer 11 and a rectifier module 12. The antenna radiating layer 11 is a butterfly-shaped metal patch with etched slots 111 on its surface. These slots help adjust the antenna impedance to better match the rectifier circuit, thereby improving rectification efficiency. By setting the metal patch of the antenna radiating layer to a butterfly shape, multiple resonant modes can be excited, covering a wider frequency range. The butterfly-shaped patch structure can guide the current to be evenly distributed along the edge of the patch, reducing current congestion and ohmic loss. Compared with the circular or rectangular patches in the prior art, the current path of the butterfly structure is longer and smoother, which is beneficial to improving radiation efficiency.

[0034] The butterfly-shaped metal patch has a feed point 112 at its center, which is electrically connected to the rectifier module 12. The rectifier module 12 includes a dielectric substrate 121 and a ground layer 122 arranged sequentially. The ground layer 122 is connected to the antenna radiating layer 11 through an array of metallized vias 123, with multiple vias 123 arranged in a ring around the edge of the antenna radiating layer 11. The array of metallized vias between the ground layer and the antenna radiating layer helps to achieve efficient electrical connection and further reduce losses. This integrated design and modular construction in terms of physical structure helps to reduce size and manufacturing cost, making it easy to integrate into small devices.

[0035] In the integrated antenna-rectifier unit, the antenna radiating layer (butterfly patch) is connected to the ground plane through a ring of metallized vias (0.3 mm in diameter and 3 mm apart) to form a current loop, optimizing antenna directivity and reducing edge radiation loss. The ground plane provides electromagnetic shielding for the antenna radiating layer, suppressing the influence of external interference signals on the rectifier circuit.

[0036] The reconfigurable frequency selection module 20 allows the antenna to adapt to microwave sources of different frequencies, increasing operational flexibility. Located above the antenna radiating layer 11, the module consists of periodic cross-shaped metal units, with a microwave rectifier element 21 (such as a rectifier diode (HSMS-2860) embedded in its center for detection or rectification circuitry. The anode of the rectifier diode (HSMS-2860) is directly soldered to the antenna radiating layer feed point, while the cathode is grounded through a via, eliminating impedance mismatch issues associated with traditional microstrip line connections. The cross-shaped metal units interact with the antenna radiating layer via electromagnetic coupling, dynamically adjusting the antenna's frequency band characteristics. By changing the conduction state of the microwave rectifier element used for detection or rectification circuitry, specific frequency bands (such as 5.8 GHz or 2.4 GHz) can be reflected or transmitted, suppressing multipath interference and optimizing energy reception efficiency. This allows the antenna to adapt to multi-band or dynamic frequency microwave sources, broadening the operating bandwidth and solving the problem of a single resonant frequency, enabling the antenna to adapt to multi-band or dynamic frequency microwave sources.

[0037] The butterfly-shaped patch forms an electromagnetic coupling with the reconfigurable frequency selection module 20 above it. By adjusting the frequency selection characteristics (such as reflection or transmission) of the reconfigurable frequency selection module 20, the frequency response of the antenna is dynamically optimized. For example:

[0038] In the 5.8 GHz band, the reconfigurable frequency selection module 20 reflects spurious signals, and the butterfly patch mainly receives 2.4 GHz of effective energy;

[0039] In the 2.4 GHz band, the reconfigurable frequency selection module 20 transmits signals, and the butterfly patch extends to 5.8 GHz high-frequency reception.

[0040] The heat dissipation layer 30 is attached to the bottom of the ground layer 122, and its surface is etched with microgrooves 31 for heat dissipation.

[0041] The micro-groove design of the heat dissipation layer helps to improve heat dissipation efficiency and prevent the rectifier circuit from degrading due to temperature rise. The heat dissipation layer is tightly attached to the ground layer and the back of the rectifier diode through thermal grease, forming an efficient heat conduction path. This not only effectively dissipates heat but also ensures the stability and reliability of the rectifier antenna during long-term operation.

[0042] A protective cover 40 covers the reconfigurable frequency selection module 20 and its surface is coated with a hydrophobic coating.

[0043] This microwave rectifier antenna is ingeniously designed. By integrating the antenna and rectifier unit together, it achieves better impedance matching, reduces energy loss caused by the separate design, and thus improves conversion efficiency. The combination of periodic cross-shaped metal elements and microwave rectifier components for detection or rectification circuits allows the antenna to operate at different frequencies, enabling dynamic adjustment of the frequency band, and it is compact in size.

[0044] Traditional rectangular or circular patches typically support only a single dominant mode and have a narrow bandwidth (<10% relative bandwidth). To achieve coverage of a wider frequency range (e.g., 2.4-5.8 GHz), the butterfly-shaped metal patch in this invention features a wingspan angle of at least 60°, a single wing length of 15 mm and a width of 10 mm, and 1.5 mm × 0.5 mm slots spaced 2 mm apart, arranged radially. This helps to broaden the antenna's bandwidth. The periodic slots etched on the butterfly patch surface can generate additional coupling resonances, further widening the bandwidth. For example, the 1.5 mm × 0.5 mm slots can excite secondary resonances at 2.4 GHz and 5.8 GHz, respectively, enabling effective operation over a wider frequency range. Furthermore, specific resonant modes can be introduced through the slots, helping to filter out desired frequencies while suppressing interference from other frequencies. The larger spread angle contributes to a wide beamwidth, allowing the antenna to receive microwave energy from a wider angle, thus improving the antenna's receiving range.

[0045] Furthermore, a Schottky diode is soldered to the feed point 112 of the antenna radiating layer 11. The anode of the diode is connected to the butterfly metal patch through a microstrip line, and the cathode is connected to the ground layer 122 through a via 123.

[0046] In this embodiment, the Schottky diode is a common high-efficiency rectifier device in the prior art. It has a low forward voltage and fast switching characteristics, which helps to improve rectification efficiency and reduce energy loss. By directly soldering the Schottky diode to the feed point of the antenna radiating layer, a high degree of integration between the antenna and the rectifier circuit is achieved, reducing external connections and lowering parasitic impedance and loss. Connecting the anode of the Schottky diode to the butterfly metal patch through a microstrip line can achieve precise impedance matching of the antenna, thereby further improving rectification efficiency. The cathode is connected to the ground plane through a via. This layout simplifies the circuit design, reduces the space occupied on the circuit board, and helps to reduce the overall size of the device.

[0047] Furthermore, the reconfigurable frequency selection module 20 has a cross-shaped metal element with an arm length of 7.5 mm, an arm width of 0.5 mm, and an element period of 15 mm. The cross-shaped metal element's structural design allows for tuning the antenna's resonant frequency by changing the element's electrical length. This design enables a wider frequency coverage range, allowing the antenna to adapt to microwave sources of different frequencies. Moreover, this cross-shaped structure provides a degree of directivity, helping to improve the antenna's gain in a specific direction.

[0048] Among them, the microwave rectifier element 21 used in the detection or rectification circuit is model BAR50-02V. This is a specially designed microwave rectifier diode with high rectification efficiency and low loss characteristics, which is suitable for microwave energy rectification. It is connected to the external controller through a flexible circuit board. The flexible circuit board can withstand a certain degree of bending and vibration, making it suitable for use in dynamic or mobile application environments. This connection method increases the flexibility of the connection, making it easier to connect the rectifier element to the external controller, and also facilitating maintenance and replacement.

[0049] Furthermore, the heat dissipation layer 30 uses an aluminum nitride ceramic substrate, which facilitates rapid heat conduction from heat sources (such as rectifier diodes), and has a thickness of 0.5 mm. The microtrench 31 has a depth of 0.2 mm and a spacing of 1 mm, and is bonded to the ground layer 122 and the back of the diode via thermal grease. The microtrench 31 not only increases the surface area of ​​the heat dissipation layer, thereby improving heat dissipation efficiency, but also helps the thermal grease to better fill the gaps between the heat dissipation layer and other components, reducing thermal resistance. The combination of aluminum nitride ceramic and microtrench provides an efficient heat dissipation path, helping to keep the rectifier diodes and other electronic components operating within a reasonable temperature range.

[0050] Furthermore, the protective cover 40 is made of a transparent polyimide film with a thickness of 0.05 mm and a transmittance of >95%, and its edges are sealed with epoxy resin. The edges of the protective cover are bonded to the dielectric substrate with epoxy resin to ensure the airtightness of the overall structure; the protective cover covers the reconfigurable frequency selection module 20 and has a transmittance of >95%, preventing physical damage to the reconfigurable frequency selection module 20 unit from the environment (such as humidity, dust);

[0051] This high-transmittance protective cover ensures that the rectifier antenna's radio frequency performance is not affected, while protecting internal components from the influence of the external environment; and the protective combination of polyimide film and epoxy resin can effectively prevent mechanical damage, moisture, dust and other environmental factors from damaging the antenna's internal structure.

[0052] Optionally, the microwave rectifier antenna may also include a DC-DC converter and an output interface;

[0053] The DC-DC converter, model LT8610, is mounted on the outside of heat sink 30. It has an input voltage of 1.8-5.5 V and an output of 5 V / 200 mA. The DC-DC converter (such as LT8610) is connected to the output of the rectifier circuit through copper pillars to convert pulsating DC power into regulated DC output. The converter casing is grounded, and the shielding layer reduces electromagnetic interference from contaminating the output signal.

[0054] Through efficient DC-DC conversion, the energy harvesting efficiency of the rectifier antenna can be maximized to provide a stable power supply for downstream devices; and the system can extract and stably output the required voltage and current from the rectified DC voltage, making it suitable for different power supply requirements.

[0055] The output interface is a Micro-USB or gold-plated test pad, which is soldered to the output of the DC-DC converter; this allows the rectifier antenna to be easily integrated with other electronic devices, whether via a standard Micro-USB interface or by soldering.

[0056] Furthermore, the dielectric substrate 121 is made of FR4 material, with dimensions of 30 mm × 30 mm × 0.8 mm, dielectric constant of 4.4, and loss tangent of 0.02. FR4 material has good thermal stability, which helps to maintain the stability of circuit performance under temperature changes. In addition, the dielectric substrate 121 can also help maintain signal integrity and reduce signal attenuation during transmission.

[0057] Collaborative workflow of each component:

[0058] 1. Microwave Reception: The butterfly patch receives microwave signals, and the electric field is evenly distributed through periodic gaps to enhance wideband reception capability. The reconfigurable frequency selection module 20 dynamically selects the operating frequency band (e.g., reflecting 5.8 GHz clutter and transmitting 2.4 GHz effective signals).

[0059] 2. Rectification and Filtering: The microwave signal is transmitted to the diode via a microstrip line and converted into pulsating DC. The LC matching circuit filters out high-frequency harmonics and optimizes the output DC quality.

[0060] 3. Heat dissipation and protection: The heat generated by the diode is transferred to the aluminum nitride heat dissipation layer through thermal grease, and then rapidly diffused through the micro-trench. The polyimide protective cover blocks external environmental corrosion and maintains the stability of the internal circuit.

[0061] 4. Energy output: The DC-DC converter outputs 5V DC power after voltage regulation, which is supplied to the load via Micro-USB interface.

[0062] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A microwave rectenna, characterized by, The integrated antenna-rectifier unit includes a fixedly connected antenna radiation layer and a rectifier module; the antenna radiation layer is a butterfly-shaped metal patch, a surface of which is etched with a slit, and a feeding point of the butterfly-shaped metal patch is electrically connected with the rectifier module; the rectifier module includes a dielectric substrate and a ground layer arranged in sequence; the ground layer is connected with the antenna radiation layer through a metallized via array, and a plurality of the vias are annularly distributed at edges of the antenna radiation layer; the reconfigurable frequency selection module is arranged above the antenna radiation layer and is composed of periodic cross-shaped metal units, and a microwave rectifying element for a detection or rectification circuit is further embedded in the center of the reconfigurable frequency selection module; the heat dissipation layer is attached below the ground layer, and a micro-groove for heat dissipation is etched on a surface of the heat dissipation layer; the protective cover is covered above the reconfigurable frequency selection module, and a hydrophobic coating is coated on a surface of the protective cover.

2. The microwave rectenna of claim 1, wherein, The two wings of the butterfly-shaped metal patch are spread at an angle of at least 60°, a single wing has a length of 15 mm and a width of 10 mm, the slit has a size of 1.5 mm*0.5 mm, a spacing of 2 mm, and is arranged in a radial manner.

3. The microwave rectenna of claim 2, wherein, The feeding point of the antenna radiation layer is welded with a Schottky diode, an anode of the diode is connected to the butterfly-shaped metal patch through a microstrip line, and a cathode is connected to the ground layer through a via hole.

4. The microwave rectenna of claim 2, wherein, The cross-shaped metal unit of the reconfigurable frequency selection module has an arm length of 7.5 mm, an arm width of 0.5 mm, and a unit period of 15 mm, and the microwave rectifying element for the detection or rectification circuit is a BAR50-02V model connected to an external controller through a flexible circuit board.

5. The microwave rectenna of claim 3, wherein, The heat dissipation layer adopts an aluminum nitride ceramic substrate with a thickness of 0.5 mm, a micro-groove depth of 0.2 mm, a spacing of 1 mm, and is attached to the ground layer and the back of the diode through a heat-conducting silicone grease.

6. The microwave rectenna of claim 5, wherein, The protective cover is made of a transparent polyimide film with a thickness of 0.05 mm, a wave permeability of >95%, and an edge sealed by epoxy resin glue.

7. The microwave rectenna of claim 1, wherein, The microwave rectifying antenna further includes a DC-DC converter and an output interface. The DC-DC converter is an LT8610 model installed on the outside of the heat dissipation layer, has an input voltage of 1.8-5.5 V, and an output of 5 V / 200 mA. The output interface is a Micro-USB or a gold-plated test pad welded on the output end of the DC-DC converter.

8. The microwave rectenna of claim 1, wherein, The dielectric substrate is made of FR4 material with a size of 30mm*30mm*0.8mm, a dielectric constant of 4.4, and a loss tangent of 0.02.

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