Circularly polarized mobile phone antenna based on single-feed self-phase-shift structure
The combination of the inner dipole and outer folded monopole antennas of the single-fed self-phase shifting structure solves the problems of complex structure and large space occupation of existing circularly polarized mobile phone antennas, achieves circular polarization effect and cost reduction, and adapts to the axial ratio performance of different environments.
Patent Information
- Application Number
- CN202510813892.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-18
- Publication Date
- 2025-09-23
AI Technical Summary
Existing circularly polarized mobile phone antenna designs require a power splitter for feeding, resulting in a complex antenna structure, large space occupation and high cost, which makes it difficult to meet the requirements of modern smartphones for compact space and diverse functions.
A single-fed self-phase shifting structure is adopted. Through the combination of the inner dipole antenna and the outer folded monopole antenna, a 90° phase difference is achieved by coaxial feeding, which simplifies the structure and reduces the feeding ports. The axial ratio characteristics of the inner dipole antenna are adjusted by adjusting the length of the bottom left arm.
The circular polarization effect is achieved, the space occupied by the antenna in the mobile phone is reduced, the production cost is reduced, and the axial ratio performance is improved by adjusting the length of the bottom left arm of the inner dipole antenna to adapt to different environments.
Smart Images
Figure CN120691099A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of antenna technology, and further relates to a circularly polarized antenna, specifically a circularly polarized mobile phone antenna based on a single-feed self-phase shifting structure, which can be used in the design of circularly polarized mobile phone antennas. Background Art
[0002] With the development of mobile communication technology, mobile phones are playing an increasingly important role in people's daily lives, and consumers are increasingly demanding the appearance and functionality of smartphones. With the successful launch of the Beidou satellite, satellite communications have gradually emerged into the public eye, providing mobile phone users with global communication services. This is especially true in remote areas and environments such as offshore, where only satellite signals can cover these areas. Unlike traditional terrestrial cellular networks, satellite communications rely on satellites orbiting above the Earth to transmit mobile phone signals to distant ground stations or other satellites, ultimately transmitting the data back to the terrestrial network. This places high demands on the polarization performance of antennas. Circularly polarized antennas, with their resistance to multipath effects and reduced polarization mismatch loss, play a vital role in satellite communications. Therefore, it is urgent to design a circularly polarized mobile phone antenna to meet these growing communication requirements.
[0003] In recent years, power dividers have attracted the attention of circularly polarized antenna design engineers because they can independently control the amplitude and phase of two antennas. In the field of mobile phone antennas, power dividers are often placed on the motherboard of the mobile phone. By designing a one-to-two power divider on the motherboard, the two vertical linear polarized antennas are fed with equal amplitude and a phase difference of 90° to achieve circular polarization. For example,
[61] Li P, Zhang Y, Qin X, Wei K, Liang P, Li YY designed a three-dipole circularly polarized mobile phone antenna in the paper "Wideband Widebeam Circular-Polarized Antenna Using Asymmetrical Tri-Dipoles for Direct Satellite-to-Handset" published in the journal EEE Transactions on Antennas and Propagation, vol. 72, no. 8, pp. 6270-6277, Aug. 2024. The three-dipole antenna is fed by an integrated power divider chip, and the phase difference between the vertically polarized dipole antennas on both sides and the horizontally polarized dipole antenna in the middle is adjusted to 90°, thereby achieving circular polarization of the antenna. At a center frequency of 3.8 GHz, the antenna has a -6dB impedance bandwidth of 680 MHz, a 3dB axial ratio bandwidth of 140 MHz, and a 3dB beamwidth exceeding 92°. However, this solution ignores the reality that the internal space of smartphones is becoming increasingly compact due to current requirements for appearance and functionality. Adding an integrated power splitter chip to the phone motherboard to feed the antenna has significant limitations and is not easy to implement. Summary of the Invention
[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and propose a circularly polarized mobile phone antenna based on a single-fed self-phase shifting structure to solve the problem caused by the need for a power divider for feeding in the design of circularly polarized mobile phone antennas. The present invention can simplify the antenna structure, reduce the space occupied by the antenna, reduce the number of antenna feeding ports and reduce the production cost.
[0005] To achieve the above objectives, the technical solutions of the present invention include the following:
[0006] A circularly polarized mobile phone antenna based on a single-feed self-phase shifting structure includes a mobile phone frame 1, a dielectric plate 2, an antenna 3, a clearance area 4, and an antenna floor 5. The antenna 3 includes an inner antenna and an outer antenna, wherein the inner antenna is a dipole antenna 6 and the outer antenna is a folded monopole antenna 7; the inner antenna and the outer antenna are located on the inner and outer layers of the mobile phone frame 1, respectively.
[0007] The dipole antenna 6 is a rectangular frame structure with an opening, connected to the ground via a grounding structure 9. The antenna consists of three parts: an upper rectangular strip, a bottom left arm, and a bottom right arm. The bottom left arm and the bottom right arm are asymmetric structures, and the antenna axial characteristics can be adjusted by adjusting the length of the bottom left arm.
[0008] The folded monopole antenna 7 is a bow-shaped structure and is fed by a coaxial feeding structure 8 .
[0009] Compared with the prior art, the present invention has the following advantages:
[0010] First, the present invention achieves a 90° phase difference between the two antennas through a single-feed self-phase shifting structure, thereby realizing circular polarization of the antennas. There is no need to design a power splitter on the mobile phone motherboard for feeding, which effectively saves the space occupied by the antenna on the mobile phone.
[0011] Second, since the antennas in the present invention are inner dipole antennas and outer monopole antennas, when the environment changes, the axial ratio can be adjusted by adjusting the length X1 of the bottom left arm of the inner dipole antenna so that its axial ratio can cover the operating frequency band of the antenna, thereby significantly improving its axial ratio performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a schematic diagram of the overall front structure of a mobile phone model equipped with the antenna of the present invention in an embodiment;
[0013] Figure 2 This is a schematic diagram of the overall structure of the back of a mobile phone model equipped with the antenna of the present invention in an embodiment;
[0014] Figure 3 Schematic diagram of the layered structure of the antenna of the present invention;
[0015] Figure 4 Schematic diagram of the structure of the inner antenna in the antenna of the present invention;
[0016] Figure 5 Schematic diagram of the structure of the outer antenna in the antenna of the present invention;
[0017] Figure 6 The return loss characteristic curve diagram in the embodiment of the present invention is
[0018] Figure 7 The axial ratio characteristic diagram of the antenna of the present invention under different parameter settings; (a) is the axial ratio characteristic diagram of the antenna of the present invention at 2.5GHz, The axial ratio of the antenna is (b) The antenna of the present invention is at 2.5GHz, 、 The axial ratio of the antenna when , and the horizontal axis is the frequency.
[0019] Figure 8 This is a comparison chart of simulation results of the relationship between the bottom left arm length X1 of the antenna in the present invention and the antenna parameters; (a) is the relationship between X1 and the antenna return loss parameter; (b) is the relationship between X1 and the antenna axial ratio parameter. DETAILED DESCRIPTION
[0020] The present invention will be further described below with reference to the accompanying drawings.
[0021] Example 1: Refer to the attached Figure 1-3 The present invention proposes a circularly polarized mobile phone antenna based on a single-feed self-phase shifting structure, comprising a mobile phone frame 1, a dielectric plate 2, an antenna 3, a clearance area 4, and an antenna floor 5; the antenna 3 comprises an inner antenna and an outer antenna, wherein the inner antenna is a dipole antenna 6 and the outer antenna is a folded monopole antenna 7; the two are respectively located on the inner and outer layers of the mobile phone frame 1;
[0022] The dipole antenna 6 is a rectangular frame structure with an opening, connected to the ground via a grounding structure 9. The antenna consists of an upper rectangular strip, a bottom left arm, and a bottom right arm. The bottom left arm and the bottom right arm are asymmetrical structures, and the antenna axial ratio characteristics are regulated by adjusting the length of the bottom left arm. In this embodiment, the left and right ends of the upper rectangular strip of the dipole antenna 6 are connected to the left end of the bottom left arm and the right end of the bottom right arm respectively via vertical rectangular strips. The length of the upper rectangular strip is set to be less than the width of the top of the mobile phone frame 1 and greater than half of that width. The antenna axial ratio characteristics are regulated by adjusting the length of the bottom left arm. In this embodiment, the length of the bottom left arm is specifically denoted as X1, and the regulation is achieved by adjusting the phase difference between the inner antenna and the outer antenna by adjusting the size of X1. The adjustment range of the bottom left arm length X1 is: greater than 0 and less than the difference between the length of the upper rectangular strip and the length of the bottom right arm, that is, the bottom left arm does not contact the bottom right arm.
[0023] The folded monopole antenna 7 has an arched structure and is fed by a coaxial feed structure 8. From top to bottom, it comprises first, second, third, and fourth horizontal sections. The right ends of the first and second horizontal sections are connected by an upper vertical section, the left ends of the second and third horizontal sections are connected by a middle vertical section, and the right ends of the third and fourth horizontal sections are connected by a lower vertical section. In this embodiment, the width of the first horizontal section is L4, and the width of the remaining horizontal sections is L5, where L5 = L4 + W2. The length of the upper vertical section is H2, and the length of the middle and lower vertical sections is H3, where H3 > H2.
[0024] Furthermore, the line widths of the dipole antenna 6 and the folded monopole antenna 7 are W1 and W2 respectively, and W1>W2.
[0025] In this embodiment, the phone frame 1 and dielectric plate 2 are both made of polytetrafluoroethylene (F4BM) high-frequency antenna material with a dielectric constant of 3.5 and a loss tangent of 0.0022. Their thicknesses range from 1mm to 1.5mm and 0.93mm to 1mm, respectively. The antenna 3 and antenna floor 5 are both made of metal materials, such as copper and aluminum. The antenna floor 5 has a thickness of 0.035mm to 0.07mm. A clearance area 4 of 0.5mm to 1mm is provided between the antenna and the floor. The inner and outer antennas are printed on the inner and outer layers of the top of the phone frame 1, respectively.
[0026] Example 2: The overall structure of the circularly polarized mobile phone antenna proposed in this example is the same as that of Example 1. Figure 1-5 , select specific size parameters and material properties, and give examples to further describe the present invention in detail.
[0027] Reference Figure 1-2 The antenna of the present invention is mounted on the top frame of the mobile phone, with a portion located on both the inner and outer sides of the frame. The dimensions of the mobile phone model used in this embodiment include a length (L) of 168mm, a width (W) of 76mm, and a height (H) of 9.2mm. These dimensions were obtained through actual measurements of a commercially available smartphone. The phone's frame and motherboard are both made of dielectric material with a dielectric constant of 3.5.
[0028] Reference Figure 3 The antenna structure in this design has inner and outer sides. The antenna is printed on the inner and outer layers of the top frame of the mobile phone. The thickness of the frame is 1mm, the material is F4B, and the dielectric constant is 3.5. The inner layer is a grounded dipole antenna 6, and the outer layer is a folded monopole antenna 7. The printed metal materials are all copper. The folded monopole antenna is fed through a coaxial feed 8, and the dipole antenna is connected to the ground through a grounding structure 9.
[0029] Reference Figure 4 The inner dipole antenna 6 in this design consists of three parts: the two arms at the bottom are asymmetric structures with lengths of X1=17mm and L2=14mm respectively; the upper rectangular strip is L3=40mm long, and the middle connecting rectangular strip has a width of W1=1mm and a height of H1=6.8mm. The antenna axial ratio can be adjusted by the length of X1. When the length of X1 changes, the phase difference between the inner antenna and the outer antenna will change accordingly, thereby changing the axial ratio characteristics of the antenna. In this example, the length of antenna X1 is set to 17mm. When the environment changes, the length of X1 can be adjusted.
[0030] Reference Figure 5In this design, the length of the upper horizontal part L4 of the outer folded monopole antenna 7 is 3.6 mm, the length of the lower horizontal part L5 is 4.2 mm, the length of the upper vertical part H2 is 3.2 mm, the length of the middle and lower vertical parts is 3.6 mm, and the antenna width W2 is 0.6 mm.
[0031] The effects of the present invention can be further illustrated with reference to simulation results:
[0032] 1. Simulation conditions:
[0033] The simulation experiment of the present invention is carried out using the commercial simulation software HFSS.
[0034] 2. Simulation content:
[0035] Simulation 1: The return loss parameters of the antenna of the present invention are simulated and calculated using the commercial simulation software HFSS. The results are as follows: Figure 6 shown.
[0036] from Figure 6 It can be seen that, with a return loss of < -6dB as the standard, the operating bandwidth of the circularly polarized mobile phone antenna based on the single-fed self-phase shifting structure proposed in the present invention covers 2.36GHz~2.76GHz, and this operating frequency band covers the satellite communication frequency band of 2.483GHz~2.5GHz.
[0037] Simulation 2, the antenna axial ratio of the antenna of the present invention is calculated using the commercial software HFSS, and the results are as follows: Figure 7 shown.
[0038] Figure 7 (a) is the antenna of the present invention at 2.5GHz, The axial ratio of the antenna is (b) is the antenna of the present invention at 2.5GHz, 、 The axial ratio of the antenna is , and the horizontal axis is the frequency. It can be seen that the circularly polarized mobile phone antenna based on the single-feed self-phase shift structure of the present invention is 2.5GHz, The 3dB axial ratio range of the antenna is ; Antenna at 2.5GHz, , The 3dB axial ratio bandwidth is 2.10GHz~2.58GHz.
[0039] Simulation 3, using commercial software HFSS to simulate the relationship between the X1 length of the antenna of the present invention and the antenna return loss parameters and axial ratio, the results are as follows Figure 8 shown; from Figure 8As can be seen from (a) and (b) in the figure, when the length of the antenna X1 of the present invention changes, the return loss parameter and the axial ratio of the antenna will change. The axial ratio of the antenna can be dynamically adjusted by adjusting the length of X1.
[0040] The above simulation results show that the present invention achieves circular polarization through a single-fed self-phase shifting structure, effectively reducing the space occupied by the antenna in the mobile phone, and making the antenna have a good circular polarization axial ratio characteristic. The axial ratio can be dynamically adjusted by changing the length of X1, so that the antenna can adapt to different working environments and has good applicability.
[0041] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, storage, and display, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. The collection, use, and processing of relevant data must comply with the laws, regulations, and standards of relevant countries and regions, and corresponding operation portals are provided for users to choose to authorize or refuse. The above simulation analysis proves the correctness and effectiveness of the method proposed in this invention.
[0042] Parts of the present invention that are not described in detail belong to common knowledge among those skilled in the art.
[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Obviously, for professionals in this field, after understanding the content and principles of the present invention, they may make various modifications and changes in form and details without departing from the principles and structure of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.
Claims
1. A circularly polarized mobile phone antenna based on a single-feed self-phase shifting structure, comprising a mobile phone frame (1), a dielectric plate (2), an antenna (3), a clearance area (4) and an antenna floor (5); characterized in that: The antenna (3) comprises an inner antenna and an outer antenna, wherein the inner antenna is a dipole antenna (6) and the outer antenna is a folded monopole antenna (7); the inner antenna and the outer antenna are located on the inner and outer layers of the mobile phone frame (1), respectively; The dipole antenna (6) is a rectangular frame structure with an opening, connected to the ground via a grounding structure (9); the antenna is composed of three parts: an upper rectangular strip, a bottom left arm, and a bottom right arm, and the bottom left arm and the bottom right arm are asymmetric structures, and the antenna axial characteristics are controlled by adjusting the length of the bottom left arm; The folded monopole antenna (7) is a bow-shaped structure and is fed via a coaxial feeding structure (8).
2. The antenna according to claim 1, wherein: The mobile phone frame (1) and dielectric plate (2) are both made of polytetrafluoroethylene F4BM high-frequency antenna plate material, with a dielectric constant of 3.5 and a loss tangent of 0.0022, and thicknesses of 1mm-1.5mm and 0.93mm-1mm respectively.
3. The antenna according to claim 1, wherein: The antenna (3) and the antenna floor (5) are both made of metal materials, including at least copper and aluminum; the antenna floor (5) has a thickness of 0.035 mm to 0.07 mm.
4. The antenna according to claim 1, wherein: The clearance area (4) is a clearance area formed between the antenna and the antenna floor, and has a size of 0.5 mm to 1 mm.
5. The antenna according to claim 1, wherein: The inner antenna and the outer antenna are specifically printed on the inner layer and the outer layer of the top of the mobile phone frame (1) respectively.
6. The antenna according to claim 1, wherein: In the dipole antenna (6), the left and right ends of the upper rectangular strip are respectively connected to the left end of the bottom left arm and the right end of the bottom right arm via vertical rectangular strips; the length of the upper rectangular strip is less than the width of the top of the mobile phone frame (1) and greater than half of the width.
7. The antenna according to claim 6, wherein: The antenna axial ratio characteristics are controlled by adjusting the length of the bottom left arm. Specifically, the length of the bottom left arm is recorded as X1, and the phase difference between the inner antenna and the outer antenna is changed by adjusting the size of X1 to complete the control. The adjustment range of the bottom left arm length X1 is: greater than 0 and less than the difference between the length of the upper rectangular strip and the length of the bottom right arm, that is, the bottom left arm does not contact the bottom right arm.
8. The antenna according to claim 1, wherein: The folded monopole antenna (7) comprises, from top to bottom, a first, a second, a third and a fourth horizontal portion, wherein the right ends of the first and second horizontal portions are connected via an upper vertical portion, the left ends of the second and third horizontal portions are connected via a middle vertical portion, and the right ends of the third and fourth horizontal portions are connected via a lower vertical portion.
9. The antenna according to claim 8, wherein: The width of the first horizontal part is L4, and the widths of the remaining horizontal parts are all L5, and L5=L4+W2; the length of the upper vertical part is H2, and the lengths of the middle and lower vertical parts are both H3, and H3>H2.
10. The antenna according to claim 1, wherein: The line widths of the dipole antenna (6) and the folded monopole antenna (7) are W1 and W2 respectively, and W1>W2.