Laminated dual-frequency circularly polarized microstrip antenna and electronic equipment
By designing a stacked dual-frequency circularly polarized microstrip antenna, using a coaxial substrate and metallized through-hole connection, and combining it with a four-phase coupler for feeding, the problem of poor isolation between the two frequencies was solved, a wider impedance bandwidth and a stable phase center were achieved, and the low elevation angle gain was enhanced.
Patent Information
- Application Number
- CN202520222305.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-12
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2035-02-12
AI Technical Summary
Existing multi-point fed microstrip antennas suffer from poor isolation between dual frequencies, while single-point fed antennas have issues such as narrow impedance bandwidth, low gain at low elevation angles, and unstable phase center.
A stacked dual-frequency circularly polarized microstrip antenna is designed, which adopts a first and a second antenna substrate coaxially arranged. A first feed probe is provided on the first substrate, and a second feed probe is provided below the second substrate. The probes are connected by through holes on the second substrate through metallization. An eight-feed point feed is achieved using a monolithic four-phase coupler. The probe positions are optimized to improve isolation.
It improves the dual-band isolation of the antenna, ensures antenna performance, achieves a wider impedance bandwidth and a stable phase center, and enhances low elevation angle gain, making it suitable for satellite communication and mobile communication fields.
Smart Images
Figure CN223583232U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of antennas, in particular to a laminated dual-frequency circularly polarized microstrip antenna and electronic equipment. BACKGROUND
[0002] In the past few decades, circularly polarized microstrip antennas have been widely concerned and applied in the fields of satellite communication and mobile communication due to their small size, light weight and low profile. With the rapid development of China's Beidou navigation positioning system technology, a high-performance navigation satellite signal receiver is needed for the satellite wireless navigation system, and the design of the receiving antenna is one of the most important parts of the entire system design, so higher requirements are put forward for the performance of the antenna. Under the condition of obtaining the required circular polarization characteristics, the impedance bandwidth is as wide as possible, the low-elevation-angle gain is improved, and the stability of the phase center is improved. The modeling of the single-point-fed cut-corner square patch antenna is very simple and easy to manufacture, and it has been widely used. However, the single-point-fed antenna has the problems of narrow impedance bandwidth, low low-elevation-angle gain and unstable phase center, and the laminated multi-point-fed microstrip antenna emerges as the times require, which can obtain good circular polarization characteristics, wide impedance bandwidth and stable phase center. However, although the laminated design can realize the dual-frequency operation of the antenna, it has the problem of poor isolation between the two frequencies. CONTENT OF THE INVENTION
[0003] The application aims at the above problems, and provides a laminated dual-frequency circularly polarized microstrip antenna and electronic equipment with good isolation between the two frequencies.
[0004] In a first aspect, the application provides a laminated dual-frequency circularly polarized microstrip antenna, which comprises:
[0005] A first antenna substrate, which has a first feed probe;
[0006] A second antenna substrate, which is arranged below the first antenna substrate and has a second feed probe; the second antenna substrate is provided with a metalized through hole for the first feed probe to pass through;
[0007] A coupler, which is connected to the first feed probe and the second feed probe;
[0008] The working frequency of the first antenna substrate is greater than the working frequency of the second antenna substrate.
[0009] According to the technical scheme provided by some embodiments of the application, the shape of the first antenna substrate is a square, and the shape of the second antenna substrate is a circle.
[0010] According to the technical scheme provided in some embodiments of the present application, the first antenna substrate and the second antenna substrate are coaxially arranged; the size of the first antenna substrate is 48.9mm*48.9mm*4mm; and the size of the second antenna substrate is Φ76mm*4mm.
[0011] According to the technical scheme provided in some embodiments of the present application, the first antenna substrate and the second antenna substrate both adopt a microwave composite dielectric copper-clad foil substrate with a dielectric constant of 4.0 and a dielectric loss tangent of 0.001 as a dielectric substrate.
[0012] According to the technical scheme provided in some embodiments of the present application, the number of the first feeding probes and the second feeding probes is both four, and the coupler adopts a single-chip four-phase coupler to perform eight-feed-point feeding.
[0013] According to the technical scheme provided in some embodiments of the present application, the four corners of the second antenna substrate are fixed to the first antenna substrate by screws.
[0014] According to the technical scheme provided in some embodiments of the present application, four slots symmetrically distributed about the central axis of the first antenna substrate are formed on the radiating patch of the first antenna substrate, and the slot openings of the slots are directed to the side edges of the first antenna substrate.
[0015] According to the technical scheme provided in some embodiments of the present application, the shape of the slot is T-shaped.
[0016] In the second aspect, the present application provides an electronic device, wherein the electronic device is installed with the laminated dual-frequency circularly polarized microstrip antenna as described in the first aspect, and is used for receiving or transmitting signals.
[0017] Compared with the prior art, the present application has the following beneficial effects: the laminated dual-frequency circularly polarized microstrip antenna provided in the present application comprises a first antenna substrate and a second antenna substrate arranged below the first antenna substrate, the first antenna substrate is provided with first feeding probes, and the second antenna substrate is provided with second feeding probes; a metalized through hole is formed on the second antenna substrate for the first feeding probes to pass through; a coupler is connected to the first feeding probes and the second feeding probes; and the working frequency of the first antenna substrate is greater than the working frequency of the second antenna substrate. The through hole formed on the second antenna substrate for the first feeding probes to pass through is subjected to metalization treatment, so that the through hole can effectively conduct current like a metal wire, thereby improving the isolation of the antenna and ensuring the performance of the antenna.
[0018] It should be understood that the description of technical features, technical solutions, advantages or similar language in this application does not imply that all features and advantages can be realized in any single embodiment. On the contrary, it can be understood that the description of features or advantages means that a specific technical feature, technical solution or advantage is included in at least one embodiment. Therefore, the description of technical features, technical solutions or advantages in this specification does not necessarily refer to the same embodiment. Further, the technical features, technical solutions and advantages described in this embodiment can be combined in any appropriate manner. Those skilled in the art will understand that the embodiments can be implemented without one or more specific technical features, technical solutions or advantages of a specific embodiment. In other embodiments, additional technical features and advantages can be identified in specific embodiments that do not embody all embodiments. BRIEF DESCRIPTION OF DRAWINGS
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings from these drawings without creating labor.
[0020] Figure 1 A top view structural schematic diagram of the stacked dual-frequency circularly polarized microstrip antenna provided in Embodiment 1 of the present application;
[0021] Figure 2 A side view structural schematic diagram of the stacked dual-frequency circularly polarized microstrip antenna provided in Embodiment 1 of the present application;
[0022] Figure 3 A schematic diagram of the connection of the first antenna substrate, the second antenna substrate and the four-phase coupler of the stacked dual-frequency circularly polarized microstrip antenna provided in Embodiment 1 of the present application;
[0023] Figure 4 Isolation simulation results of the stacked dual-frequency circularly polarized microstrip antenna provided in Embodiment 1 of the present application after via metallization processing;
[0024] Figure 5 A current distribution diagram of the stacked dual-frequency circularly polarized microstrip antenna provided in Embodiment 1 of the present application with a first slot shape;
[0025] Figure 6 A current distribution diagram of the stacked dual-frequency circularly polarized microstrip antenna provided in Embodiment 1 of the present application with a first slot shape;
[0026] Figure 7 A current distribution diagram of the stacked dual-frequency circularly polarized microstrip antenna provided in Embodiment 1 of the present application with a first slot shape;
[0027] Figure 8 The current distribution diagram of the stacked dual-frequency circularly polarized microstrip antenna with the first slot shape is provided for Embodiment 1 of the present application.
[0028] The text annotations in the figure represent:
[0029] 1, first antenna substrate; 2, second antenna substrate; 3, slot. DETAILED DESCRIPTION
[0030] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings, and the description in this part is only exemplary and explanatory, and should not have any limiting effect on the protection scope of the present application. Specifically, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.
[0031] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0032] Embodiment 1
[0033] Please refer to Figure 1 The present embodiment provides a stacked dual-frequency circularly polarized microstrip antenna, the operating frequency of which is B1 and B3 frequency bands of Beidou III. The antenna performance requirements are: 1, antenna beam: 0-360 degrees in azimuth, 5-90 degrees in elevation; 2, normal gain: 2dBi; 3, polarization: right-hand circular polarization (RHCP); 4, normal axial ratio: 3dB; 5, phase center stability: ±2mm.
[0034] Based on the above antenna performance requirements, a stacked dual-frequency circularly polarized microstrip antenna is designed, which comprises:
[0035] The first antenna substrate 1 has a first feed probe thereon;
[0036] The second antenna substrate 2 is arranged below the first antenna substrate 1, and has a second feeding probe; the second antenna substrate 2 is provided with a metalized through hole for the first feeding probe to pass through;
[0037] The coupler connects the first feeding probe and the second feeding probe;
[0038] The working frequency of the first antenna substrate 1 is greater than the working frequency of the second antenna substrate 2.
[0039] Specifically, the antenna substrate is an important component of the microstrip antenna structure, and the structure of the antenna substrate of the microstrip antenna mainly includes three parts: a dielectric substrate, a radiation patch arranged on the dielectric substrate, and a feeding structure for transmitting signals to the radiation patch, wherein the shape of the radiation patch can be square, rectangular, circular, oval, etc. The embodiment is a laminated microstrip antenna, which includes a first antenna substrate 1 and a second antenna substrate 2 arranged in layers, wherein the first antenna substrate 1 includes a first dielectric substrate, a first radiation patch arranged on the first dielectric substrate, and a first feeding probe for transmitting signals to the first radiation patch, and the second antenna substrate 2 includes a second dielectric substrate, a second radiation patch arranged on the second dielectric substrate, and a second feeding probe for transmitting signals to the second radiation patch.
[0040] Further, the number of the first feeding probe and the second feeding probe is four, that is, the microstrip antenna provided in the embodiment is an eight-feed microstrip antenna. Among them, the four first feeding probes are uniformly and symmetrically distributed about the central axis of the first antenna substrate 1, the four first feeding probes are located on the same circle (marked as the first circle), and the central angle formed by the connecting line of the adjacent two first feeding probes and the center of the first circle is 90°; the four second feeding probes are uniformly and symmetrically distributed about the central axis of the second antenna substrate 2, the four second feeding probes are located on the same circle (marked as the second circle), and the central angle formed by the connecting line of the adjacent two second feeding probes and the center of the second circle is 90°, the diameter of the second circle is greater than the diameter of the first circle, and the first feeding probe adjacent to the position of any second feeding probe is located on a diameter of the second circle. By optimizing the positions of the eight probes, the impedance matching of the antenna is ensured, and the performance requirements of the antenna are met.
[0041] In order to improve the isolation degree of the frequency points of the first antenna substrate 1 and the second antenna substrate 2, the four first feeding probes of the upper first antenna substrate 1 are subjected to metalization treatment at the four through holes on the lower second antenna substrate 2, that is, the through holes on the second antenna substrate 2 for the first feeding probe to pass through are subjected to metalization treatment, that is, a continuous metal conductive layer is formed on the side wall of the through hole, so that the through hole can effectively conduct current like a metal wire. The metal conductive layer is made of copper, gold, tin, etc. Reference Figure 4The isolation of the dual-frequency points is increased from about 10dB to about 27dB, i.e. the isolation is increased by 17dB, which ensures the performance of the antenna.
[0042] Further, the first antenna substrate 1 and the second antenna substrate 2 both adopt a microwave composite dielectric copper-clad foil substrate with a dielectric constant of 4.0 and a dielectric loss tangent of 0.001 as a dielectric substrate.
[0043] Specifically, according to the design requirements, in the design of the microstrip antenna of the application, first, the dielectric substrate is selected, and in this embodiment, two pieces of microwave composite board with the same dielectric constant are used as the substrate to realize the dual-frequency operation of the Beidou third-generation B1 and B3 frequency band antennas. The first dielectric substrate of the first antenna substrate 1 and the second dielectric substrate of the second antenna substrate 2 both adopt a microwave composite dielectric copper-clad foil substrate with a dielectric constant of 4.0 and a dielectric loss tangent of 0.001. Secondly, the selection of the feeding mode, generally, a complex microstrip line feeding network or three integrated 3dB 90° hybrid bridges are used for feeding in a four-feed microstrip antenna, and the circuit is complex. In this embodiment, a single four-phase coupler is used to realize the feeding of the eight feed points of the two-layer antenna to realize the right-hand circular polarization of the antenna, and the feeding network is simple and easy to integrate with microwaves. As shown in Figure 3 The four-phase coupler N1 has two input ends, and the two input ends are connected with the output end of the first antenna substrate 1 and the output end of the second antenna substrate 2 respectively. The four-phase coupler N1 also has eight output ends, four of which are used for connection with the first antenna substrate 1, and the other four are connected with the second antenna substrate 2. The size of the four-phase coupler N1 is 5.08mm×3.18mm×0.6mm.
[0044] Further, the first antenna substrate 1 and the second antenna substrate 2 are coaxially arranged; the size of the first antenna substrate 1 is 48.9mm×48.9mm×4mm; and the size of the second antenna substrate 2 is Φ76mm×4mm.
[0045] Specifically, the embodiment adopts a stacked structure with a lower circular upper layer. The lower layer is a circular second antenna substrate 2 with a dielectric substrate diameter of 76 mm and a thickness of 4 mm. The upper layer is a square first antenna substrate 1 with a dielectric substrate side length of 48.9 mm and a thickness of 4 mm. The central axis of the first antenna substrate 1 coincides with the central axis of the second antenna substrate 2, i.e., they are coaxially arranged. This has the following advantages. First, it makes the electric field distribution of the antenna more concentrated and symmetrical, thereby improving the directivity of the antenna and enhancing the radiation intensity of the antenna in a specific direction, which is beneficial to improving the transmission efficiency and reception sensitivity of signals. For example, in satellite communication, the antenna can be better aligned with the satellite to enhance the strength of the communication signal. Second, it is conducive to the mutual coupling of electromagnetic fields between different layers. This coupling effect can produce multiple resonance frequencies, thereby effectively widening the frequency bandwidth of the antenna and enabling it to work in a wider frequency range to meet the needs of multiple communication frequency bands. For example, in modern wireless communication systems, multiple frequency bands such as 2G, 3G, 4G, and even 5G can be covered simultaneously. Third, it helps to optimize the input impedance of the antenna, making it more matched with the impedance of the feed line, thereby reducing the reflection coefficient, reducing signal reflection at the feed port, improving the power transmission efficiency of the antenna, and ensuring that the antenna can effectively receive and transmit signals, avoiding energy loss and signal interference caused by signal reflection. In addition, the coaxially arranged substrate structure is more stable, which can reduce the deformation of the antenna structure caused by external factors such as vibration and impact, thereby ensuring the stability of the performance of the antenna and prolonging the service life of the antenna. It is suitable for various complex working environments such as vehicle-mounted, ship-mounted, aerospace, etc.
[0046] Further, the four corners of the second antenna substrate 2 are fixedly connected to the first antenna substrate 1 by screws.
[0047] Specifically, mounting holes are provided at the four corners of the first antenna substrate 1, and screws are passed through the mounting holes to realize the mounting and fixation of the first antenna substrate 1 and the second antenna substrate 2. To facilitate the installation of the screws and avoid affecting the performance of the antenna, the size of the radiation patch on the first antenna substrate 1 is slightly smaller than that of the dielectric substrate, and the four corners thereof are chamfered.
[0048] Further, the size of the radiation patch of the second antenna substrate 2 is also slightly smaller than that of the dielectric substrate, and four protrusions are uniformly provided around the edges of the radiation patch.
[0049] Specifically, the four protrusions are provided to facilitate the adjustment of the antenna by the adjustment personnel by changing the size of the protrusions, so as to reduce errors. Through the optimization of the size of the antenna radiation patch, the working frequency of the antenna is ensured to be in the B1 and B3 frequency bands.
[0050] Further, the radiation patch of the first antenna substrate 1 is provided with four slots 3 symmetrically distributed about the central axis of the first antenna substrate 1, and the slot openings of the slots 3 face the side edges of the first antenna substrate 1.
[0051] Specifically, in order to reduce the size of the patch while keeping the dielectric constant of the substrate unchanged, the square radiation patch of the first antenna substrate 1 is provided with slots on four sides respectively, as shown in the figure. Figure 1 In this embodiment, the slots 3 are T-shaped, and the slot openings of the T-shaped slots 3 face the outside of the radiation patch of the first antenna substrate 1. The results show that, before the slots are opened, the side length of the dielectric substrate of the first antenna substrate 1 is 56 mm, and the side length of the radiation patch is 46.9 mm. After the slots are opened, the size of the dielectric substrate of the first antenna substrate 1 is reduced to 48.9 mm, and the side length of the radiation patch is reduced to 41 mm, i.e. the size of the antenna is reduced by 12.6%.
[0052] In addition, the provision of the slots 3 brings many benefits: first, it can effectively increase the bandwidth of the antenna. The slots 3 can change the current distribution of the antenna, making the current path longer. For example, the current path originally concentrated on the edge of the patch will change due to the presence of the slots 3, and the current will be redistributed along the edge of the slots 3, so that the antenna can resonate in a wider frequency range, thereby increasing the bandwidth of the antenna. Second, it can change the electromagnetic field distribution inside the antenna, forming multiple different resonance modes, which is similar to introducing a new inductance-capacitance combination in a circuit, producing a new resonance frequency. For example, for a microstrip antenna designed to work at 2.4 GHz, by reasonably designing the size and position of the T-shaped slots, the antenna can have an additional resonance frequency of, for example, 5.8 GHz based on 2.4 GHz, thereby meeting the needs of dual-frequency communication. Third, the presence of the slots 3 changes the equivalent circuit parameters of the antenna, such as the values of inductance and capacitance. By adjusting the size (length, width, etc.) of the slots 3, the input impedance of the antenna can be adjusted to better match the characteristic impedance of the feed line. For example, when the characteristic impedance of the feed line is 50 Ω, by optimizing the structure of the slots 3, the input impedance of the antenna can be made close to 50 Ω, thereby reducing the reflection loss and improving the radiation efficiency of the antenna.
[0053] It should be noted that the shape of the slots 3 can also be umbrella-shaped, Y-shaped, and symmetric S-shaped, etc.
[0054] Reference is made to the T-shaped slots 3 in Figures 5-8 ,the Y-shaped slots 3 in Figure 5 , the umbrella-shaped slots 3 in Figure 6 , and the symmetric S-shaped slots 3 in Figure 7 . Figure 8
[0055] The stacked dual-frequency circularly polarized microstrip antenna provided by the application has the following characteristics: a simple feed network, a single four-phase coupler for realizing dual-frequency eight-feed-point feed, small antenna patch size under the same dielectric constant and thickness, high isolation of the stacked dual-frequency antenna, compact structure, easy microwave integration, excellent circularly symmetric upper half-beam, good wide-angle circular polarization, stable phase center, and the like. The antenna has high low-elevation-angle gain, strong low-elevation-angle satellite tracking capability, and ensures that the number of available satellites is sufficient; the antenna can be used with various Beidou receivers and is widely used in navigation scheduling, tracking monitoring, measurement and control, and military fields.
[0056] Embodiment 2
[0057] The embodiment provides an electronic device, which is provided with the stacked dual-frequency circularly polarized microstrip antenna as described in Embodiment 1, and is used for receiving or transmitting signals.
[0058] The principles and implementation manners of the application are described by using specific examples in the present application. The above description of the embodiments is only used to help understand the method of the application and its core idea. The above description is only the preferred embodiments of the application. It should be pointed out that, due to the limited expression, there are infinite specific structures. For ordinary skilled persons in the art, without departing from the principles of the application, a number of improvements, refinements or changes can be made, or the above technical features can be combined in an appropriate manner; the improvements, refinements, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, shall be regarded as the protection scope of the application.
Claims
1. A stacked dual-frequency circularly polarized microstrip antenna, characterized in that, include: A first antenna substrate, wherein the first antenna substrate has a first feed probe; The second antenna substrate is disposed below the first antenna substrate and has a second feed probe; The second antenna substrate has a metallized through-hole that allows the first feed probe to pass through; A coupler that connects the first feed probe and the second feed probe; The operating frequency of the first antenna substrate is greater than that of the second antenna substrate.
2. The stacked dual-frequency circularly polarized microstrip antenna according to claim 1, characterized in that, The first antenna substrate is square in shape; the second antenna substrate is circular in shape.
3. The stacked dual-frequency circularly polarized microstrip antenna according to claim 2, characterized in that, The first antenna substrate and the second antenna substrate are coaxially arranged; the dimensions of the first antenna substrate are 48.9mm×48.9mm×4mm; the dimensions of the second antenna substrate are Φ76mm×4mm.
4. The stacked dual-frequency circularly polarized microstrip antenna according to claim 1, characterized in that, Both the first antenna substrate and the second antenna substrate use microwave composite dielectric copper-clad foil substrates with a dielectric constant of 4.0 and a dielectric loss tangent of 0.001 as dielectric substrates.
5. The stacked dual-frequency circularly polarized microstrip antenna according to claim 1, characterized in that, The number of the first and second feed probes are both four, and the coupler is a monolithic four-phase coupler for eight-feed point feeding.
6. The stacked dual-frequency circularly polarized microstrip antenna according to claim 2, characterized in that, The four corners of the second antenna substrate are fixed to the first antenna substrate by screws.
7. The stacked dual-frequency circularly polarized microstrip antenna according to claim 2, characterized in that, The first antenna substrate has four slots symmetrically distributed about the central axis of the first antenna substrate on its radiating patch, with the slot openings facing the side of the first antenna substrate.
8. The stacked dual-frequency circularly polarized microstrip antenna according to claim 7, characterized in that, The slot is T-shaped.
9. An electronic device, characterized in that, The electronic device is equipped with a stacked dual-frequency circularly polarized microstrip antenna as described in any one of claims 1-8, for receiving or transmitting signals.