Feed network and directional diagram shaped antenna

Abstract

The invention relates to a feed network and a directional diagram shaped antenna. The feed network is arc-shaped, a plurality of power dividers are arranged on the arc-shaped structure at equal intervals, and the power dividers are connected through phase shift transmission lines; a plurality of metal columns are further arranged near the circle center of the arc-shaped structure, and the metal columns are annularly arranged at equal intervals; the power dividers are connected with the metal columns through impedance conversion transmission lines for signal transmission. The feed network is good in symmetry, isolation resistance can be reduced, and transmission loss can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a feeding network and a directional pattern shaping antenna. Background Art

[0002] The feed network is a circuit structure used to transmit and distribute radio frequency signals in the antenna system. Its main function is to send signals from the transmitter to the various radiating elements of the antenna, or to transmit the received signals from the antenna back to the receiver. It not only ensures the effectiveness of signal transmission, but also needs to optimize the radiation pattern and directivity of the antenna by adjusting the amplitude and phase of each antenna element. Depending on the frequency, power and structural requirements, the feed network can take many forms, such as coaxial cable, microstrip line, waveguide and power divider.

[0003] Traditional feed networks often have problems with poor symmetry, which will lead to uneven signal strength and phase received by antenna units. This imbalance will cause instability and distortion of the antenna radiation beam, especially in large-scale antenna arrays, where insufficient symmetry will significantly weaken the system's gain and radiation efficiency.

[0004] In addition, the traditional feeding network has large isolation resistance and transmission loss. Large isolation resistance will reduce the signal transmission quality and may also cause an increase in the standing wave ratio, which will lead to increased system energy loss and reflected power. High loss can easily reduce the transmission efficiency of the system and cause a decrease in the radiation performance of the antenna, affecting the overall reliability and service life of the antenna system.

[0005] Therefore, when designing the feeding network, special attention should be paid to factors such as symmetry, impedance matching and transmission loss to ensure efficient operation and stable performance of the antenna system. Summary of the invention

[0006] Based on this, it is necessary to provide a feeding network and directional pattern shaping antenna with good symmetry, equal power distribution and equal phase difference, which can reduce isolation resistance and transmission loss in order to solve the above technical problems.

[0007] A feeding network, the feeding network is in an arc shape, a plurality of power dividers are arranged at equal intervals on the arc structure, and the power dividers are connected by phase-shifted transmission lines; A plurality of metal columns are arranged near the center of the arc-shaped structure, and the metal columns are arranged at equal intervals in the circumferential direction; Each of the power dividers is connected to the metal pillars along the radial direction of the arc-shaped structure through an impedance conversion transmission line.

[0008] In one of the embodiments, the power divider adopts a microstrip structure.

[0009] In one embodiment, the bandwidths of the phase-shifted transmission lines between the power dividers are different.

[0010] In one embodiment, the impedance conversion transmission line includes a first impedance conversion transmission line and a second impedance conversion transmission line; The input end of the first impedance conversion transmission line is connected to the power divider, and the output end is connected to the input end of the second impedance conversion transmission line; the output end of the second impedance conversion transmission line is connected to the metal column; The first impedance-transformed transmission line and the second impedance-transformed transmission line have different bandwidths.

[0011] In one embodiment, a bandwidth of the first impedance-transformed transmission line is smaller than a bandwidth of the second impedance-transformed transmission line.

[0012] In one embodiment, the first impedance transformation transmission line is a quarter-wavelength impedance transformation transmission line.

[0013] In one embodiment, the characteristic impedance of the second impedance transformation transmission line is the same as that of the feed antenna.

[0014] A directional pattern shaping antenna adopts the feeding network structure to shape the directional pattern of the antenna.

[0015] In one embodiment, the directional pattern shaping antenna further includes: a feed antenna, a metal ground plate and a partial reflective surface; The partial reflective surface is coaxially suspended above the feed antenna; the metal ground plate is located below the feed antenna and is coaxially connected to the feed antenna; The feeding network is arranged below the metal ground plate and connected to the feed antenna, and is used to divide the input signal into a plurality of outputs, and provide excitation of a set phase difference for the feed antenna.

[0016] In one embodiment, the partial reflective surface includes a dielectric substrate and a plurality of polygonal metal patches printed on the lower surface of the dielectric substrate; The reflection coefficient of the partial reflection surface is adjusted by adjusting the angle of the polygonal metal patch.

[0017] Compared with the prior art, the feeding network and directional pattern shaping antenna provided by the present invention have the following effects: 1. The feeding network provided by the present invention can distribute the power dividers at equal intervals within a range of 360 degrees through an arc-shaped design, with good symmetry, and can ensure the same electrical distance of the signal on each power divider and transmission path, thereby making the electrical performance of each branch tend to be consistent, effectively reducing signal interference and intermodulation distortion, and improving the stability and consistency of the feeding network.

[0018] 2. Symmetrical design can reduce irregularities and impedance mismatches on the signal transmission path, thereby reducing the need for isolation resistors. In addition, the interference between transmitted signals is small, which also helps to reduce the mutual influence between channels and improve signal isolation.

[0019] 3. The symmetrical layout reduces the dispersion of the electromagnetic field and unnecessary losses. In addition, the power divider is set on the arc-shaped structure, the metal column is set near the center of the circle, and the power divider is connected to the metal column radially. This straight-line connection method can shorten the connection distance, so that more energy can be effectively transmitted, reducing the overall transmission loss. In addition, impedance conversion is also realized, guiding horizontal transmission to vertical transmission.

[0020] 4. The symmetrical feeding network structure design can maintain the phase consistency of each channel, thereby reducing the phase error, further reducing the energy loss of the signal and improving the overall transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0022] Figure 1 A schematic diagram of the overall structure of the feeding network provided in Example 1; Figure 2 A schematic diagram of the detailed structure of the feed network provided in Example 1; Figure 3 A schematic diagram of signal transmission in a feed network provided in Example 1; Figure 4 An axonometric diagram of the directional pattern shaping antenna provided in Example 2; Figure 5 A horizontal schematic diagram of the directional pattern shaping antenna provided in Example 2; Figure 6 A schematic diagram of the feed antenna structure provided in Example 2; Figure 7 A schematic diagram of the metal ground plate structure provided in Example 2; Figure 8 A schematic diagram of a partial reflective surface structure provided in Example 2; Fig. 9 A schematic diagram of antenna standing wave ratio provided in Example 2; Fig.10 A schematic diagram of the power division ratio of the feeding network provided in Example 2; Fig.11 A schematic diagram of the simulation results of the directional pattern of the antenna provided in Example 2 at a frequency of 5.01 GHz; Fig.12 A schematic diagram of the simulation results of the directional pattern of the antenna provided in Example 2 at a frequency of 5.02 GHz; Fig.13 A schematic diagram of the simulation results of the directional pattern of the antenna provided in Example 2 at a frequency of 5.03 GHz; Fig.14 A schematic diagram of the simulation results of phase fluctuation jitter of the antenna provided in Example 2 at a frequency of 5.01 GHz; Fig.15 A schematic diagram of the simulation results of phase fluctuation jitter of the antenna provided in Example 2 at a frequency of 5.02 GHz; Fig.16 This is a schematic diagram of the simulation results of phase fluctuation jitter of the antenna provided in Example 2 at a frequency of 5.03 GHz.

[0023] Description of reference numerals: Feed network 1, substrate 10, power divider 11, input end 111, first power divider 112, second power divider 113, third power divider 114, phase-shifted transmission line 12, first phase-shifted transmission line 121, second phase-shifted transmission line 122, third phase-shifted transmission line 123, metal column 13, first metal column 131, second metal column 132, third metal column 133, fourth metal column 134, impedance conversion transmission line 14, first impedance conversion transmission line 141, second impedance conversion transmission line 142; pattern shaping antenna 2, feed antenna 21, helix 211, balun 212, dielectric column 213, disk 214, metal ground plate 22, groove 221, second via 222, partial reflection surface 23, dielectric substrate 231, polygonal metal patch 232.

[0024] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0028] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In addition, the detachable connection mentioned in the present invention includes but is not limited to snap connection, threaded connection, pin connection, magnetic connection, plug-in connection, etc., which can be adaptively selected according to the situation. The specific detachable connection method in the following embodiment is one of the practicable methods and is not the only limitation.

[0030] It can be understood that the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0031] The following will describe the implementation of the present invention in detail with reference to the accompanying drawings in the embodiment diagram of the present invention.

[0032] Example 1 Reference 1 to Figure 3As shown, a feeding network is provided, in which the feeding network 1 is in an arc shape, and a plurality of power dividers 11 are arranged at equal intervals on the arc structure, and the power dividers 11 are connected by phase-shifting transmission lines 12; a plurality of metal columns 13 are also arranged near the center of the arc structure, and the metal columns 13 are arranged at equal intervals in a circumferential direction; and the power dividers 11 are connected to the metal columns 13 along the radial direction of the arc structure through impedance conversion transmission lines 14.

[0033] By designing the feed network 1 as a whole into such an arc-shaped structure, the power dividers 11 can be evenly spaced within a 360-degree range, and the metal columns 13 can also be evenly spaced, so that the feed network 1 forms a symmetrical structure. This symmetrical design can ensure that the signal has the same electrical distance on each power divider 11 and the transmission path, thereby making the electrical performance of each branch tend to be consistent, effectively reducing signal interference and intermodulation distortion, and improving the stability and consistency of the feed network 1. It can also reduce irregularities and impedance mismatches on the signal transmission path, thereby reducing the need for isolation resistors. In addition, the interference between the transmitted signals is small, which also helps to reduce the mutual influence between the channels and improve the isolation of the signal. Furthermore, the symmetrically distributed layout reduces the dispersion of the electromagnetic field and unnecessary losses; at the same time, the power divider 11 is set on the arc-shaped structure, the metal column 13 is set near the center of the circle, and the power divider 11 is connected to the metal column 13 in the radial direction. This straight-line connection method can shorten the connection distance, so that more energy is effectively transmitted, and the overall transmission loss is reduced. In addition, the symmetrical feeding network structure design can maintain the phase consistency of each channel, thereby reducing the phase error, further reducing the energy loss of the signal and improving the overall transmission efficiency.

[0034] Specifically, the feeding network 1 is a microstrip structure printed on a dielectric substrate 10. The microstrip structure design has the advantages of small size, light weight, easy manufacturing and integration. The outer contour of the feeding network 1 is an arc-shaped structure, and the arc-shaped structure facilitates the reasonable distribution of the power divider 11 within a range of 360°. Several power dividers 11 are evenly distributed on the arc-shaped structure. In the feeding network 1 of this embodiment, three power dividers 11 are evenly distributed on the arc-shaped structure, and the angle between adjacent power dividers 11 is 90°, which is used to divide the input signal into four equal amplitudes and phase differences of 90°. It can be understood that the number of power dividers 11 is set according to demand. In order to facilitate understanding and explanation, three power dividers 11 are set in the feeding network 1 of this embodiment for structural schematic description, but it is not intended to limit the present invention.

[0035] On the arc-shaped structure, one end is used as the input end 111, and starting from the input end 111, the first power divider 112, the second power divider 113, and the third power divider 114 are sequentially arranged along the annular direction. Among them, the first power divider 112 is a 3:1 power divider, the second power divider 113 is a 2:1 power divider, and the third power divider 114 is a 1:1 equal power divider. The power dividers 11 are connected by phase-shifted transmission lines 12, and the phase-shifted transmission lines 12 are arc-shaped. The arcs of the phase-shifted transmission lines 12 together form the arc-shaped outer contour of the feeding network 1; in addition, the bandwidth of each phase-shifted transmission line 12 is designed to have different widths according to requirements.

[0036] Near the center of the arc-shaped structure, a plurality of metal pillars 13 are arranged in a circular direction, and the number of the metal pillars 13 is set according to demand. For example, in this embodiment, the input RF signal is equally divided into four paths by three power dividers 11, so four metal pillars 13 are required for signal transmission. When it is set to 4 metal pillars 13, the angle between adjacent metal pillars 13 is 90°, and the setting direction of each metal pillar 13 is perpendicular to the plane formed by the feeding network 1, and extends upward through the substrate 10 to be connected to the feed antenna 21.

[0037] The three power dividers 11 are respectively connected to the corresponding metal pillars 13 through impedance conversion transmission lines 14, and the impedance conversion transmission lines 14 include a first impedance conversion transmission line 141 and a second impedance conversion transmission line 142; the input end of the first impedance conversion transmission line 141 is connected to the power divider 11, and the output end is connected to the input end of the second impedance conversion transmission line 142; the output end of the second impedance conversion transmission line 142 is connected to the metal pillar 13. The bandwidths of the first impedance conversion transmission line 141 and the second impedance conversion transmission line 142 are designed to have different widths according to requirements. In this embodiment, the bandwidth of the first impedance conversion transmission line 141 is smaller than the bandwidth of the second impedance conversion transmission line 142. In addition, the fourth metal pillar 134 is directly connected to the phase-shift transmission line 12 through the second impedance conversion transmission line 142. It can be understood that in this embodiment, the phase-shift transmission line 12 connected to the fourth metal pillar 134 is regarded as an impedance conversion transmission line, and its characteristic impedance and bandwidth can be designed to be the same as those of the first impedance conversion transmission line 141.

[0038] More specifically, the first impedance conversion transmission line 141 is a quarter-wavelength impedance conversion transmission line. The characteristic impedance of the second impedance conversion transmission line 142 is the same as that of the feed antenna 21, and the corresponding bandwidth is designed based on this.

[0039] When transmitting signals, Figure 3As shown, after the RF signal is input from the input terminal 111, the signal is divided into a first branch signal and a second branch signal through the first power divider 112, wherein the first branch signal is fed to the first metal column 131 through the impedance conversion transmission line 14, and the second branch signal is further transmitted to the second power divider 113 through the first phase-shift transmission line 121. The second power divider 113 divides the second branch signal into a third branch signal and a fourth branch signal, wherein the third branch signal is fed to the second metal column 132 through the impedance conversion transmission line 14, and the fourth branch signal is further transmitted to the third power divider 114 through the second phase-shift transmission line 122. The third power divider 114 divides the fourth branch signal into a fifth branch signal and a sixth branch signal, wherein the fifth branch signal is fed to the third metal column 133 through the impedance conversion transmission line 14. The sixth branch signal is further transmitted through the third phase-shift transmission line 123, and then fed to the fourth metal column 134 through the second impedance conversion transmission line 142. When transmitting a signal, the phase-shifting transmission line 12 is mainly used to change the phase of the signal, and the impedance conversion transmission line 14 is used to achieve impedance matching.

[0040] In addition, this embodiment provides how to design the characteristic impedance and bandwidth of the phase-shift transmission line 12 .

[0041] like Figure 3 As shown, it is known that the resistance of the first power divider 112 is R1, the resistance of the second power divider 113 is R2, the resistance of the third power divider 114 is R3, and Z in1 , Z in2 , Z in3 , Z in4 , Z in5 and Z in6 They respectively represent the input impedance from the output end of each power divider 11 to the load end, and the load end includes the phase-shift transmission line 12 and the load. The characteristic impedance of the first impedance conversion transmission line 141 through which the first branch signal, the third branch signal, and the fifth branch signal pass is X 0, the characteristic impedance of the phase-shift transmission line 12 through which the sixth branch signal passes is X 4.

[0042] The power divider 11 must meet two conditions when designing: 1. No reflection at the input end; 2. The output voltage at the output end is equal in amplitude and phase. Assume that the characteristic impedance of the transmission line at the input end 111 is X1=50Ω, and the RF signal is input from the input end 111. The characteristic impedance of the four second impedance conversion transmission lines 142 is R load The impedances of all phase-shift transmission lines 12 are 50Ω. By calculating in reverse, the characteristic impedance and bandwidth of each phase-shift transmission line 12 can be obtained. Specifically, the calculation expression is as follows: Z in6 =X0 2 / 50, similarly for Zin4 =X0 2 / 50, Z in2 =X0 2 / 50; Since X4=X0; Z in5 =X0 2 / 50; 1 / R3=1 / Z in5 +1 / Z in6 ; Z in3 =X3 2 / R3; 1 / R2=1 / Z in3 +1 / Z in4 ; Z in1 =X2 2 / R2; 1 / R1=1 / Z in1 +1 / Z in2 ; Assume that in order to achieve reflection-free transmission at the input port of the power divider, R1=50Ω. In this way, by solving various equations simultaneously, the characteristic impedances X2, X3, and X4 of the first phase-shifted transmission line 121, the second phase-shifted transmission line 122, and the third phase-shifted transmission line 123 can be calculated, and then the corresponding bandwidth can be determined based on X2, X3, and X4, so as to design the entire feeding network structure.

[0043] Example 2 refer to Figures 4 to 8 As shown, a directional pattern shaping antenna is provided, including a feed network 1, a feed antenna 21, a metal ground plate 22 and a partial reflector 23; the partial reflector 32 is coaxially suspended above the feed antenna 21; the metal ground plate 22 is located below the feed antenna 21 and is coaxially connected to the feed antenna 21; the feed network 1 is arranged below the metal ground plate 22 and is connected to the feed antenna 21, and is used to divide the radio frequency signal into a plurality of outputs, and provide an excitation with a set phase difference for the feed antenna 21. A semi-open resonant cavity is formed by the partial reflector 32 and the metal ground plate 22 together, and the electromagnetic wave radiated by the feed source located between the two oscillates back and forth on the upper and lower surfaces of the resonant cavity. By adjusting the reflection coefficient r of the partial reflector 23, the incident wave can be reflected multiple times between the partial reflector 32 and the metal ground plate 22 of the resonant cavity to obtain in-phase superposition, and then enhanced on the outside of the resonant cavity.

[0044] Specifically, the feeding network 1 adopts the structure of Example 1, which is used to divide the RF signal into four equal-amplitude excitations with a phase difference of 90° through a power divider 11, a phase-shifting transmission line 12 and an impedance conversion transmission line 14, and feeds them one by one to the feed antenna 21. Its specific structure has been described in detail in Example 1 and will not be repeated here.

[0045] The feed antenna 21 includes four identical spirals 211, a balun 212 conforming to an inverted trapezoid, and a dielectric column 213. The four identical spirals 211 are wound around the dielectric column 213 at equal intervals. By properly adjusting the radius, pitch, and number of turns of the spirals 211, the direction of the maximum gain of the antenna can be changed. The bottom of each spiral 211 is connected to an inverted trapezoidal conformal balun 212. The dielectric column 213 is composed of a thinner support structure at the upper part and a fixed structure with a disk 214 at the lower part. Four first vias are provided at the connection between the upper and lower parts. The positions of the first vias correspond to the positions of the four metal columns 13 to facilitate the connection between each metal column 13 of the feed network 1 and each spiral 211.

[0046] A metal ground plate 22 is provided between the feed antenna 21 and the feed network 1. The metal ground plate 22 is a cylindrical cavity structure with a groove 221 on the upper surface. Four second vias 222 are provided in the groove 221. The positions of the second vias 222 correspond to the positions of the four metal pillars 13. The feed network 1 is located below the metal ground plate 22. On the one hand, it can ensure unidirectional radiation and improve directional gain. On the other hand, it can provide good shielding for the feed network 1 below. In the feed network 1, the metal pillars 13 connected to the output ends of each second impedance conversion transmission line 142 pass through the corresponding second vias 222 and the first vias, respectively, and then are welded to the balun 212, so as to better match the 50Ω second impedance conversion transmission line 142 in the feed network 1.

[0047] The partial reflective surface 23 includes a dielectric substrate 231 and a plurality of polygonal metal patches 232 printed on the lower surface of the dielectric substrate 231. In order to ensure that the partial reflective surface 23 can be stably fixed at a certain height directly above the feed antenna 21, the partial reflective surface 23 can be designed as a dielectric cavity structure, or a plurality of dielectric pins can be embedded; the polygonal metal patches 232 are used to facilitate angle adjustment, thereby adjusting the reflection coefficient of the partial reflective surface 23. Preferably, the polygonal metal patches 232 can adopt a rhombus metasurface structure. It is worth noting that the partial reflective surface 23 can also adopt a partial reflective surface based on a single-layer or multi-layer dielectric plate, or a partial reflective surface of other metasurface structures.

[0048] The directional pattern shaped antenna provided in this embodiment can obtain different beam shapes by adjusting the radius, pitch, number of turns of the four helices 211 and the height of the helices and the floor, and make the electric field superimposed at low elevation angles, and finally obtain a wide beam, saddle-shaped directional pattern. The power divider 11 based on the microstrip structure and the first impedance conversion transmission line 141 can divide the input RF signal into four signals with equal amplitude and phase difference of 90°, and feed them to the feed antenna 21 with four helices 211. The metal ground plate 22 and the partial reflection surface 23 based on the rhombus metasurface structure together constitute a semi-open resonant cavity, and the incident wave is superimposed in phase through multiple reflections between the metal ground plate 22 and the partial reflection surface 23 of the resonant cavity, and then enhanced on the outside of the resonant cavity, thereby achieving the effect of increasing the gain. In addition, compared with the traditional shaped spherical reflection surface, the resonant cavity with a planar structure has a significant reduction in processing difficulty, and the corresponding processing cost is also lower and more economical.

[0049] In one of the embodiments, the performance of the directional pattern shaping antenna provided by the present invention is verified.

[0050] See also Fig. 9 , is a schematic diagram of the antenna standing wave ratio in the present invention, where the horizontal axis Freq represents the frequency in GHz, the vertical axis VSWR (1) represents the standing wave ratio in dB, and m1 is the standing wave ratio of the antenna at a frequency of 5.1 GHz. As can be seen from the figure, the present invention achieves an impedance bandwidth of 4.8 to 5.2 GHz, which indicates that the antenna designed in the present invention has good transmission performance in this frequency band.

[0051] See also Fig.10 , is a schematic diagram of the power division ratio of each port of the feed network in the present invention, in which the horizontal axis Freq represents the frequency in GHz, and the vertical axis Y1 represents the ratio of the power of each output port to the input port in dB. As can be seen from the figure, the amplitude of each output port of the feed network is between -6.26 and -6.51 dB, which is very close to the ideal value of -6dB, which shows that the antenna designed by the present invention divides the input signal into four equal parts.

[0052] See also Fig.11 , is a schematic diagram of the simulation results of the directional pattern of the antenna provided by the present invention at a frequency of 5.01 GHz, wherein the horizontal axis Theta represents the elevation angle, in deg, and the vertical axis RealizedGainLHCP represents the gain of the antenna in left-hand circular polarization, in dB. As can be seen from the figure, the gain of this embodiment in the normal 0° direction is 0.83 dBi, and the gain at an off-axis ±66° is about 4.7 dBi.

[0053] See also Fig.12, is a schematic diagram of the simulation results of the directional pattern of the antenna provided by the present invention at a frequency of 5.02GHz, in which the horizontal axis Theta represents the elevation angle in degrees, and the vertical axis RealizedGainLHCP represents the left-hand circular polarization gain of the antenna in dB. As can be seen from the figure, the gain of this embodiment in the normal 0° direction is 0.67dBi, and the gain at an off-axis ±66° is about 4.7dBi.

[0054] See also Fig.13 , which is a schematic diagram of the simulation results of the directional pattern of the antenna provided by the present invention at a frequency of 5.03 GHz. As can be seen from the figure, the gain of this embodiment in the normal 0° direction is 0.51 dBi, and the gain at an off-axis ±66° direction is about 4.7 dBi.

[0055] from Figures 11 to 13 It can be seen that the antenna designed in the present invention has the characteristics of low elevation angle and high gain. This design is very suitable for satellite payloads, ensuring that the signals transmitted to the earth can receive equal power in different regions of the ground terminal.

[0056] See also Fig.14 , is a schematic diagram of the simulation results of the phase fluctuation jitter of the antenna provided by the present invention at the frequency point of 5.01GHz. The horizontal axis Theta in the figure represents the pitch angle, in deg, and the vertical axis RealizedGainLHCP represents the left-hand circular polarization gain of the antenna, in dB. Through rough calculation, the phase center stability of this frequency point is 1.25mm.

[0057] See also Fig.15 , which is a schematic diagram of the simulation results of the phase fluctuation jitter of the antenna provided by the present invention at the frequency point of 5.02GHz. The horizontal axis Theta in the figure represents the pitch angle, in deg, and the vertical axis RealizedGainLHCP represents the left-hand circular polarization gain of the antenna, in dB. Through rough calculation, the phase center stability of this frequency point is 1.25mm. See also Fig.16 , is a schematic diagram of the simulation results of the phase fluctuation jitter of the antenna provided by the present invention at the frequency point of 5.03GHz. The horizontal axis Theta in the figure represents the pitch angle, in deg, and the vertical axis RealizedGainLHCP represents the left-hand circular polarization gain of the antenna, in dB. Through rough calculation, the phase center stability of this frequency point is 1.25mm.

[0058] from Figures 14 to 16 It can be seen that the antenna designed in the present invention has a phase pattern with a small fluctuation range and a stable phase center. This characteristic will help improve the ranging accuracy.

[0059] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A feeding network, characterized in that: The feed network is in an arc shape, and a plurality of power dividers are arranged at equal intervals on the arc structure, and the power dividers are connected by phase-shifted transmission lines; A plurality of metal columns are arranged near the center of the arc-shaped structure, and the metal columns are arranged at equal intervals in the circumferential direction; Each of the power dividers is connected to the metal pillars along the radial direction of the arc-shaped structure through an impedance conversion transmission line.

2. The feeding network according to claim 1, characterized in that The power divider adopts a microstrip structure.

3. The feeding network according to claim 1, characterized in that The bandwidths of the phase-shift transmission lines between the power dividers are different.

4. The feeding network according to claim 1, characterized in that The impedance conversion transmission line includes a first impedance conversion transmission line and a second impedance conversion transmission line; The input end of the first impedance conversion transmission line is connected to the power divider, and the output end is connected to the input end of the second impedance conversion transmission line; the output end of the second impedance conversion transmission line is connected to the metal column; The first impedance transformed transmission line and the second impedance transformed transmission line have different bandwidths.

5. The feeding network according to claim 4, characterized in that The bandwidth of the first impedance transformed transmission line is smaller than the bandwidth of the second impedance transformed transmission line.

6. The feeding network according to claim 5, characterized in that The first impedance conversion transmission line is a quarter-wavelength impedance conversion transmission line.

7. The feeding network according to claim 5, characterized in that The characteristic impedance of the second impedance transformation transmission line is the same as that of the feed antenna.

8. A directional pattern forming antenna, characterized in that: The feeding network described in any one of claims 1 to 7 is used to shape the antenna's directional pattern.

9. The directional pattern forming antenna according to claim 8, characterized in that: The directional pattern shaping antenna also includes: a feed antenna, a metal ground plate and a partial reflective surface; The partial reflective surface is coaxially suspended above the feed antenna; the metal ground plate is located below the feed antenna and is coaxially connected to the feed antenna; The feeding network is arranged below the metal ground plate and connected to the feed antenna, and is used for dividing the radio frequency signal into a plurality of outputs, and providing excitation of a set phase difference for the feed antenna.

10. The directional pattern forming antenna according to claim 9, characterized in that: The partial reflective surface includes a dielectric substrate and a plurality of polygonal metal patches printed on the lower surface of the dielectric substrate; The reflection coefficient of the partial reflection surface is adjusted by adjusting the angle of the polygonal metal patch.

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