Double-fed GNSS (Global Navigation Satellite System) antenna for optimizing circular polarization axial ratio and electronic equipment

Abstract

The utility model discloses a doubly-fed GNSS antenna for optimizing circular polarization axial ratio and an electronic device, comprising a PCB and a ceramic chip, the ceramic chip is a dielectric substrate with a silver surface and is arranged on the PCB; the at least two feed pins are respectively arranged on the silver surface of the ceramic chip at intervals and are used for receiving and transmitting polarized wave signals; the silver surface is provided with at least one or more cutting angles capable of optimizing the target isolation degree between the two feed needles, two paths of signals which are sent by the two feed needles and have the phase difference of 90 degrees are received through the signal coupler, the two paths of signals are converted into same-phase signals and synthesized, and therefore the circularly polarized antenna with the optimized circularly polarized axial ratio is formed. By optimizing the geometrical shape of the feed structure, the circular symmetry of an antenna radiation field is improved, and the axial ratio stability is improved.

Description

Technical Field

[0001] This utility model relates to the field of satellite navigation antenna technology, and in particular to a doubly fed GNSS antenna and electronic equipment for optimizing the circular polarization axial ratio, which is suitable for scenarios with high requirements for multipath suppression and positioning accuracy, such as vehicle navigation and UAV positioning. Background Technology

[0002] GNSS antennas need to achieve high-purity circularly polarized waves to suppress multipath effects. Traditional single-feed microstrip antennas have narrow axial ratio bandwidth, and the axial ratio deteriorates significantly over a wide angle range.

[0003] Doubly fed antennas generate circularly polarized waves through orthogonal feeding, but insufficient symmetry at the feeding point or phase errors can easily cause the axial ratio to deviate from the ideal value (more than 3dB), especially in dynamic vehicle scenarios, where the performance degrades when the antenna is tilted. Existing technologies optimize the axial ratio by adding parasitic patches or dielectric layers, but these methods are complex and costly. Therefore, it is necessary to propose a low-cost and easily fabricated structural improvement scheme. Utility Model Content

[0004] The purpose of this invention is to provide a dual-fed GNSS antenna and electronic equipment for optimizing the axial ratio of circular polarization. It proposes a low-cost and easy-to-manufacture structural improvement scheme, which improves the circular symmetry of the antenna radiation field and enhances the stability of the axial ratio by optimizing the geometry of the feeding structure.

[0005] This invention provides a dual-fed GNSS antenna for optimizing the circular polarization axial ratio, comprising:

[0006] PCB board

[0007] A ceramic sheet, which is a dielectric substrate with a silver surface, is disposed on the PCB;

[0008] At least two feed pins are respectively spaced apart on the silver surface of the ceramic sheet for receiving and transmitting polarized wave signals;

[0009] The silver surface is provided with at least one or more cutting angles that can optimize the target isolation between the two feed pins.

[0010] Specifically, the system receives two signals with a 90-degree phase difference from the two feed pins through a signal coupler, converts the two signals into signals with the same phase, and combines them to form a circularly polarized antenna with an optimized circular polarization axial ratio.

[0011] Preferably, the silver surface is provided with a first cutting angle and a second cutting angle, or a third cutting angle and a fourth cutting angle, and the first cutting angle and the second cutting angle... 、 Both the third and fourth cutting angles are set diagonally.

[0012] Preferably, one or more slots are provided at the edge of the silver surface to adjust the offset frequency of the adjustment needle.

[0013] Preferably, one or more slit structures are provided at the edge of the silver surface to change the current distribution on the antenna surface to adjust the offset frequency of the feed pin.

[0014] Preferably, two feed needles are disposed together on the silver surface, and the two feed needles operate at the same frequency.

[0015] Preferably, the surface area of ​​the silver surface is smaller than the surface area of ​​the ceramic sheet.

[0016] Preferably, the GNSS antenna operates at a frequency of 1559MHz-1608MHz.

[0017] Preferably, the GNSS antenna is a single-frequency dual-fed GNSS antenna or extended to a two-layer dual-frequency quad-fed antenna.

[0018] Preferably, the GNSS antenna is square or circular in shape.

[0019] This invention also provides an electronic device, including a doubly fed GNSS antenna for optimizing the circular polarization axial ratio as described in this embodiment.

[0020] This invention, by adopting the above technical solutions, has the following advantages and positive effects compared with the prior art: The dual-fed GNSS antenna for optimizing the circular polarization axial ratio provided by this invention improves the circular symmetry of the antenna radiation field by optimizing the geometry of the feeding structure, thereby enhancing the stability of the circular polarization axial ratio and enabling the antenna to receive circularly polarized signals more effectively; the proposed structural improvement scheme considers cost-effectiveness and ease of processing, enabling the antenna to be mass-produced without significantly increasing costs; by setting a chamfer on the silver surface, the isolation between the two feed pins is optimized, reducing mutual interference and improving the overall performance of the antenna; the slotted and chamfered edge structure of the silver surface allows for fine-tuning of the antenna's resonant frequency by adjusting the offset frequency of the feed pins, increasing design flexibility; the two feed pins are jointly set on the silver surface and operate at the same frequency, ensuring signal consistency and facilitating signal synthesis and processing; the surface area of ​​the silver surface is smaller than that of the ceramic sheet, which helps to reduce the overall antenna size and is suitable for space-constrained electronic devices; it covers the main GNSS signal frequency bands, ensuring effective operation within these bands, enabling the reception of signals from more GNSS systems, and improving the accuracy and reliability of positioning. Attached Figure Description

[0021] Figure 1 This is an example diagram of a doubly fed GNSS antenna for optimizing the circular polarization axial ratio in an embodiment of this utility model;

[0022] Figure 2 This is an example diagram of the debugging of a doubly fed GNSS antenna used to optimize the circular polarization axial ratio in an embodiment of this utility model;

[0023] Figure 3 An example diagram illustrating the introduction of a cut-off angle for a dual-fed GNSS antenna used to optimize the circular polarization axial ratio in this embodiment of the present invention;

[0024] Figure 4 and Figure 5 These are waveform diagrams for debugging using a conventional antenna and waveform diagrams for debugging using the antenna in this embodiment, respectively. Figure 6 This is a comparison chart of the axial ratios of two antenna tuning methods. Detailed Implementation

[0025] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the vehicle logo switching device and control method proposed in this utility model. The advantages and features of this utility model will become clearer from the following description and claims.

[0026] like Figure 1 As shown, this utility model provides a dual-fed GNSS antenna for optimizing the circular polarization axial ratio, comprising: a PCB board 100, a ceramic plate 101, a silver surface 102, feed pins 103 and 104, and a coupler (signal coupler). Specifically,

[0027] PCB board 100,

[0028] Ceramic sheet 101, which is a dielectric substrate with a silver surface 102, is disposed on the PCB; at the same time, the dielectric substrate can also be a non-ceramic dielectric.

[0029] At least two feed pins 103 and 104 are respectively spaced on the silver surface 102 of the ceramic plate 101 for receiving and transmitting polarized wave signals. Their silver surfaces are used to form the radiating surface of the antenna. The design of these two feed pins enables them to receive circularly polarized waves from the satellite, but each feed pin individually receives linearly polarized waves.

[0030] The silver surface 102 is provided with at least one or more chamfered angles that can optimize the target isolation between the two feed pins, introducing the concept of adjusting the chamfered angle of the ceramic antenna. The position and shape of these chamfered angles are designed to optimize the isolation between the two feed pins and reduce mutual interference, such as... Figure 3 By chopping at angles of 110, 111, or 112, 112, the asymmetry caused by the environment or the debugging itself is corrected, the isolation between the two feed pins is improved, and the axis ratio is improved. The specific two opposite angles to be cut need to be determined according to the actual situation, because cutting the opposite angles causes the frequency of the feed pins to shift. The frequency is then adjusted by cutting the edges or slotting.

[0031] The antenna employs a signal coupler to receive two signals from two feed pins that are 90 degrees out of phase. These signals are then converted into in-phase signals and combined to form a circularly polarized antenna with an optimized axial ratio. Essentially, the working principle involves two feed pins receiving circularly polarized waves from a satellite, while a single feed pin receives a linearly polarized wave. These two linearly polarized waves have equal amplitude and are 90 degrees out of phase. The coupler converts these two 90-degree phase-difference signals into in-phase signals and combines them. When the two signals are combined, due to their 90-degree phase difference, the combined signal forms a rotating electromagnetic field in a plane perpendicular to the feed pin axis. This is a characteristic of circularly polarized waves. By setting a chamfer on the silver surface, the mutual coupling between the two feed pins can be reduced, improving their isolation. This helps maintain a stable phase difference between the output signals of the two feed pins, thereby improving the circular polarization axial ratio. The chamfered angle design helps maintain the stability of the phase difference and amplitude of the output signals from the two feed pins, directly leading to an improved circular polarization axial ratio. This allows the antenna to radiate circularly polarized waves more effectively. The above scheme optimizes the isolation between the feed pins by setting a chamfered angle on the silver surface and maintains the stability of the phase difference and amplitude of the two signals through a signal coupler, thus improving the antenna's circular polarization axial ratio and making it closer to the ideal circular polarization characteristics. Compared to linearly polarized antennas, using a ceramic circularly polarized antenna results in no polarization loss and doubles the receiving performance.

[0032] Debugging solution as follows Figure 2 Taking feed pin 103 as an example, the resonant frequency can be shifted higher by cutting edges 106 and 107. The resonant frequency can be shifted lower by slotting positions 108 and 109. This method allows the feed pin to operate at the desired frequency. Feed pin 104 is adjusted using the same method. Traditional adjustment schemes simply use the aforementioned cutting and slotting methods to adjust the frequencies of the two feed pins to the operating frequency. Due to environmental asymmetry or the asymmetry of the cut surfaces, this adjustment method is not optimal for the isolation between the two feed pins, and the antenna axial ratio is also not optimal.

[0033] In one embodiment, a first cut angle is provided on the silver surface 102. 110 Second cutting angle 111 Or the third cutting angle 112 and the fourth cutting angle 113, and the first cutting angle 110 Second cutting angle 111、Both the third cut-off angle 112 and the fourth cut-off angle 113 are diagonally arranged. This diagonal arrangement helps reduce electromagnetic coupling between the two feed pins, thereby improving their isolation and reducing signal interference, allowing each feed pin to operate more independently. Increased isolation allows for a more accurate 90-degree phase difference between the output signals of the two feed pins, crucial for forming circularly polarized waves; therefore, the cut-off angle design improves the antenna's circular polarization performance. The diagonal cut-off angle also balances the antenna's radiation characteristics in two orthogonal planes, improving performance consistency across multiple directions. Furthermore, it reduces unnecessary frequency shifts caused by coupling between feed pins, improving the antenna's operating frequency stability. The diagonal cut-off angle also helps reduce the effects of cross-polarization, i.e., reducing radiation in non-target polarization directions, which improves signal quality and reliability. By reducing internal coupling and optimizing radiation patterns, the overall efficiency of the antenna is improved, meaning the antenna can more effectively convert electrical signals into electromagnetic waves.

[0034] In one embodiment, one or more cutting structures 106, 107 are provided at the edge of the silver surface 102 to change the current distribution on the antenna surface to adjust the offset frequency of the feed pin. For PIN1, i.e., feed pin 103, if the antenna resonant frequency is too low, the adjustment method is to provide one or more cutting structures 106, 107, which can be understood as shifting the frequency to a higher frequency by cutting the upper and lower edges 106, 107.

[0035] In one embodiment, one or more slots 108, 109 are provided at the edge of the silver surface 102 to adjust the offset frequency of the feed pin. If the resonant frequency is too high, the frequency is reduced by the slots 108, 109. The same adjustment method is used to adjust the frequency of PIN2, i.e., feed pin 104.

[0036] The principle behind this embodiment is as follows: Currently, traditional tuning methods for dual-fed GNSS ceramic antennas only adjust the frequencies of both feed pins to the required operating frequencies, without considering the isolation between them. This results in a less than ideal axial ratio, affecting actual positioning accuracy. The antenna described above improves the isolation between the two feed pins by chamfering the silver surface of the ceramic antenna at specific locations, such as 45° clockwise or 45° counterclockwise at the feed pin positions. However, setting a chamfer at a specific location on the ceramic antenna to improve isolation alters the antenna's operating frequency. Therefore, it is necessary to create a chamfered edge structure or slot on the square silver surface to correct the frequency.

[0037] In one embodiment, two feed pins 103 and 104 are jointly disposed on the silver surface 102, and the two feed pins 103 and 104 operate at the same frequency. This improves the isolation between the two feed pins from approximately 12dB to approximately 17dB. The antenna's vertex-to-axis ratio is optimized from 5 to less than 3, while the gain is also improved by approximately 1dB, thus enhancing antenna performance. Similarly, the same debugging method applies to dual-band dual-layer ceramic antennas, and this method can also be extended to circular ceramic antennas and applied to antennas.

[0038] In one embodiment, the surface area of ​​the silver surface 102 is smaller than that of the ceramic sheet. The reduced surface area of ​​the silver surface can reduce the path of surface current, thereby reducing current loss on the silver surface and improving radiation efficiency. The smaller silver surface helps to concentrate electromagnetic energy, making the main radiation direction of the antenna clearer and helping to improve the directivity of the antenna. The smaller silver surface means that edge effects (such as scattering and reflection of edge fields) are relatively reduced, which helps to improve the consistency and stability of the antenna.

[0039] In one embodiment, the GNSS antenna operates at a frequency of 1559MHz-1608MHz. The center frequencies of PIN1 and PIN2 need to be adjusted to around 1585MHz. Then, the two signals are combined by a coupler to form a 90-degree phase difference, thereby forming a right-hand circularly polarized antenna.

[0040] In one embodiment, the GNSS antenna is a single-frequency dual-fed GNSS antenna or extended to a two-layer dual-frequency quad-fed antenna. The design of a single-frequency dual-fed or two-layer dual-frequency quad-fed GNSS antenna can significantly improve the antenna's performance, making it more suitable for complex and ever-changing application environments, while providing users with more accurate and reliable positioning services.

[0041] In one embodiment, the GNSS antenna is square or circular in shape. Square antennas are generally simpler to design, easier to implement on a PCB board, and have better structural stability, making them easier to install and fix. The edges of a square shape may result in specific impedance characteristics, which can be optimized through design to improve impedance matching and reduce signal reflection. Square antennas may also be more compatible with PCB manufacturing processes, thus reducing production costs. Circular antennas typically have better omnidirectionality. The design of a circular antenna helps to generate symmetrical radiation patterns, which helps to reduce the impact of multipath effects and improve positioning accuracy. Circular antennas also have more uniform impedance in all directions, which helps to achieve better broadband performance.

[0042] Figure 4 and Figure 5These are the S-parameters obtained using the traditional debugging method and the debugging method of this embodiment, respectively. It can be seen that using the cut-off angle setting debugging method of this embodiment can improve the isolation between the two feed pins from -17dB to approximately -33dB. This significantly improves the isolation between the two feed pin supports (the S11 of the antenna feed pin itself does not change much, proving that the characteristics of the individual antenna have not changed significantly). Figure 6 This is a comparison chart of the shaft ratios of the two debugging methods. It can be seen that the shaft ratio can be significantly improved by using this embodiment.

[0043] This invention also provides an electronic device, including a doubly fed GNSS antenna for optimizing the circular polarization axial ratio as described in the above embodiments. The principle is the same as above and will not be repeated here.

[0044] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A doubly-fed GNSS antenna for optimizing the circular polarization axial ratio, characterized in that, include: PCB board A ceramic sheet, which is a dielectric substrate with a silver surface, is disposed on the PCB; At least two feed pins are respectively spaced apart on the silver surface of the ceramic sheet for receiving and transmitting polarized wave signals; The silver surface is provided with at least one or more cutting angles that can optimize the target isolation between the two feed pins. Specifically, the system receives two signals with a 90-degree phase difference from the two feed pins through a signal coupler, converts the two signals into signals with the same phase, and combines them to form a circularly polarized antenna with an optimized circular polarization axial ratio.

2. The doubly-fed GNSS antenna for optimizing the circular polarization axial ratio as described in claim 1, characterized in that, The silver surface is provided with a first cutting angle and a second cutting angle, or a third cutting angle and a fourth cutting angle, and the first cutting angle and the second cutting angle, the third cutting angle and the fourth cutting angle are all arranged diagonally.

3. The doubly-fed GNSS antenna for optimizing the circular polarization axial ratio as described in claim 1, characterized in that, One or more slots are provided at the edge of the silver surface to adjust the offset frequency of the adjustment needle.

4. The doubly-fed GNSS antenna for optimizing the circular polarization axial ratio as described in claim 1, characterized in that, One or more slit structures are provided at the edge of the silver surface to change the current distribution on the antenna surface in order to adjust the offset frequency of the feed pin.

5. The doubly-fed GNSS antenna for optimizing the circular polarization axial ratio as described in claim 1, characterized in that, Two feed needles are set together on the silver surface, and the two feed needles operate at the same frequency.

6. The doubly-fed GNSS antenna for optimizing the circular polarization axial ratio as described in claim 1, characterized in that, The surface area of ​​the silver surface is smaller than the surface area of ​​the ceramic sheet.

7. The doubly-fed GNSS antenna for optimizing the circular polarization axial ratio as described in claim 1, characterized in that, The GNSS antenna operates at a frequency of 1559MHz-1608MHz.

8. The doubly-fed GNSS antenna for optimizing the circular polarization axial ratio as described in claim 1, characterized in that, The GNSS antenna is a single-frequency dual-fed GNSS antenna or extended to a two-layer dual-frequency quad-fed antenna.

9. The doubly-fed GNSS antenna for optimizing the circular polarization axial ratio as described in claim 1, characterized in that, The GNSS antenna is square or circular in shape.

10. An electronic device, characterized in that, Includes a doubly fed GNSS antenna for optimizing the circular polarization axial ratio as described in any one of claims 1 to 9.

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