Frequency diversity and polarization diversity transmission system based on diversity antennas

Abstract

The application provides a frequency diversity and polarization diversity transmission system based on diversity antennas, comprising a diversity antenna subsystem, a radio frequency feeding network and a baseband processing unit, the diversity antenna subsystem comprises a first diversity antenna, a second diversity antenna and a metal floor, the first diversity antenna and the second diversity antenna are both at least dual-frequency antennas and are placed in space orthogonally, the radio frequency feeding network comprises a signal phase shifter, an equivalent phase shifter, a power divider and a signal amplifying device, and can realize frequency diversity and twice polarization diversity. The frequency diversity and polarization diversity transmission system based on diversity antennas provided by the application realizes the collaborative innovation of a radio frequency front end and a baseband processing unit, and constructs a complete radio frequency baseband architecture which can simultaneously and actively realize the collaborative processing of polarization diversity and frequency diversity.

Description

Technical Field

[0001] This invention belongs to the field of multi-antenna and diversity antenna technology, and more specifically, relates to a frequency diversity and polarization diversity transmission system based on diversity antennas. Background Technology

[0002] With the evolution from 5G to 6G, building an integrated air-space-ground network has become an inevitable trend. Smartphones and other mobile terminals need to simultaneously support direct communication with terrestrial cellular networks and satellites to ensure continuous and reliable connectivity across the entire coverage area. However, satellite communication downlink faces severe transmission challenges: on the one hand, the signal propagation environment is complex and susceptible to multipath fading, polarization rotation, and interference, requiring communication equipment to possess polarization diversity and circular polarization characteristics; on the other hand, the convergence of multi-band services such as navigation (L-band) and broadband data (C / Ku / Ka-band) requires terminals to have frequency diversity capabilities. From a signal transmission theory perspective, solving these challenges requires the coordinated use of polarization diversity and frequency diversity. While circularly polarized waves can suppress multipath interference, they still face signal fading due to polarization mismatch when the terminal's attitude changes; dual-band operation naturally provides opportunities for frequency diversity. Theoretically, if a collaborative processing architecture capable of simultaneously achieving polarization diversity and frequency diversity can be built on the terminal side, it will achieve anti-fading performance far superior to a single diversity approach, thereby significantly improving link reliability, system throughput, and overall communication quality.

[0003] However, the key obstacle to achieving this "dual diversity collaboration" is not the performance of the antenna elements themselves. Existing technologies mainly suffer from the following limitations: conventional solutions focus on optimizing the physical performance of antenna elements for a specific single frequency band (such as L-band only). Even solutions that attempt to integrate multiple antennas in the terminal to cover different frequency bands only achieve physical stacking of the antennas. Their design goals remain limited to extending bandwidth coverage or improving isolation, without designing "dual diversity collaboration" as a system-level goal. The fundamental problem is that the realization and performance ceiling of dual diversity heavily depend on innovation in the entire RF architecture, rather than improvements to the antenna structure alone. In existing architectures, antennas, feed networks, RF channels, and baseband processors are typically designed and optimized in isolation, lacking a systematic collaborative mechanism to actively generate and control orthogonally circularly polarized far-field radiated signals in dual-band environments. Real-time, adaptive collaborative processing (such as polarization matching, frequency band selection, and diversity merging) is required for signals from different polarizations and frequency bands. Dual-band signal processing, in particular, requires complex RF phase-shifting networks and corresponding filters and low-noise amplifiers for collaborative filtering and signal integration of multi-frequency signals. On top of this, processing dual-channel or multi-channel RF architectures with polarization diversity becomes even more complex. Summary of the Invention

[0004] The purpose of this invention is to provide a frequency diversity and polarization diversity transmission system based on diversity antennas, aiming to provide a dual- or multi-channel RF baseband architecture that coordinates polarization diversity and frequency diversity processing.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a frequency diversity and polarization diversity transmission system based on a diversity antenna, comprising:

[0006] The diversity antenna subsystem includes a first diversity antenna, a second diversity antenna, and a metal ground plane. Both the first diversity antenna and the second diversity antenna are at least dual-band antennas. The operating frequency bands of the first diversity antenna and the second diversity antenna have at least two overlapping or approximately overlapping frequency bands. The first diversity antenna and the second diversity antenna are spatially orthogonal.

[0007] The radio frequency (RF) feed network includes a signal phase shifter, an equivalent phase shifter, a power divider, and a signal amplification device. The signal phase shifter is connected to the rear end of the first diversity antenna. The equivalent phase shifter is equivalent to the phase center offset generated by the first diversity antenna, the second diversity antenna, and the metal ground plane. The power divider is used to combine the signal output from the signal phase shifter and the signal output from the second diversity antenna. The signal amplification device is used to amplify the signal output from the power divider. When the signals from the first diversity antenna and the second diversity antenna at different frequencies are combined by the power divider, frequency diversity is achieved. When the signals from the first diversity antenna and the second diversity antenna at the same frequency are combined by the power divider, first polarization diversity is achieved based on the spatial orthogonal arrangement of the first diversity antenna and the second diversity antenna, and second polarization diversity is achieved based on the RF feed network.

[0008] The baseband processing unit is used to receive and process the radio frequency signal output by the signal amplification device.

[0009] Optionally, under the influence of the signal phase shifter, the first diversity antenna and the second diversity antenna generate a relative phase shift at a first frequency. a 1. The first diversity antenna and the second diversity antenna generate a relative phase shift at the second frequency. a 2, Under the influence of the equivalent phase shifter, the first diversity antenna and the second diversity antenna produce a relative phase shift at the first frequency. b 1. The first diversity antenna and the second diversity antenna produce a relative phase shift at the second frequency. b 2, b 1 and b 2. Mutual decoupling.

[0010] Optionally, the signal received by the first diversity antenna, after passing through the signal phase shifter and the equivalent phase shifter, becomes the first signal. E 1. The signal received by the second diversity antenna is the second signal. E 2, the first signal E 1 includes a first component signal at a first frequency and a second component signal at a second frequency, the second signal... E 2 includes a third component signal at the first frequency and a fourth component signal at the second frequency, wherein the phase difference between the first component signal and the third component signal is ( a 1+ b 1) For The phase difference between the second sub-signal and the fourth sub-signal ( a 2+ b 2) for ,in, n It is an integer.

[0011] Optionally, the power divider receives the combining signal. ,

[0012] ,

[0013] ,but

[0014] ,

[0015] That is, the first sub-signal and the third sub-signal are combined to form a right-hand circularly polarized signal, and the second sub-signal and the fourth sub-signal are combined to form a left-hand circularly polarized signal, so as to achieve the second polarization diversity;

[0016] in, ω 1 corresponds to the first frequency. ω 2 corresponds to the second frequency. A 1 represents the amplitude of the first diversity antenna at the first frequency. A 2 represents the amplitude of the first diversity antenna at the second frequency. B 1 represents the amplitude of the second diversity antenna at the first frequency. B 2 represents the amplitude of the second diversity antenna at the second frequency. A 1≈ B 1, A 2≈ B 2; a The phase shift generated by the second diversity antenna to the power divider at the first frequency. b The phase shift generated by the second diversity antenna to the power divider at the second frequency.

[0017] Optionally, the baseband processing unit includes a first chip and a second chip;

[0018] The signal amplification device includes a signal amplifier that receives signals of the first frequency and the second frequency, and transmits the signal of the first frequency to the first chip and the signal of the second frequency to the second chip; or...

[0019] The signal amplification device includes two signal amplifiers, one of which receives a signal of a first frequency and transmits the signal of the first frequency to the first chip, and the other of which receives a signal of a second frequency and transmits the signal of the second frequency to the second chip.

[0020] Optionally, the first frequency is 1.5 GHz to 1.6 GHz, and the second frequency is 3.7 GHz to 3.9 GHz.

[0021] Optionally, the first diversity antenna and the second diversity antenna have the same structure.

[0022] Optionally, the first diversity antenna includes two symmetrically arranged strip structures, one of which is connected to the signal phase shifter, and the other of which is connected to the metal ground plane.

[0023] Optionally, the strip structure is provided with a tuning device for adjusting the first frequency and the second frequency, the tuning device including a capacitor and / or an inductor.

[0024] Optionally, it further includes a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate arranged orthogonally in pairs. The signal phase shifter and the power divider are disposed on one side of the first dielectric substrate in the thickness direction, the metal ground plane is disposed on the other side of the first dielectric substrate in the thickness direction, the first diversity antenna is disposed on the second dielectric substrate, and the second diversity antenna is disposed on the third dielectric substrate.

[0025] The beneficial effects of the frequency diversity and polarization diversity transmission system based on diversity antennas provided by this invention are as follows: Compared with the prior art, the frequency diversity and polarization diversity transmission system based on diversity antennas of this invention includes a diversity antenna subsystem, an RF feed network, and a baseband processing unit. The diversity antenna subsystem includes a first diversity antenna and a second diversity antenna. The first and second diversity antennas achieve frequency diversity when signals at different frequencies are combined. The first and second diversity antennas are spatially orthogonal, enabling the two diversity antennas to achieve the first polarization diversity when signals at the same frequency are combined. After passing through a signal phase shifter and an equivalent phase shifter, the first and second diversity antennas achieve the second polarization diversity when signals at the same frequency are combined. Through the collaborative innovation of the RF front-end and baseband processing, a complete RF baseband architecture capable of simultaneously and actively achieving coordinated processing of polarization diversity and frequency diversity is constructed. This architectural innovation is expected to achieve significantly better anti-multipath performance, higher link reliability, and greater system throughput under the same antenna unit conditions, bringing a breakthrough improvement to the performance of terminal satellite communication. At the same time, it can reduce the number of signal amplification devices while ensuring dual diversity collaborative operation, and also reduce the use of filters and low-noise amplifiers (equivalent to the integration of amplifiers and filters), thereby minimizing the complexity of the system and the cost of the RF baseband link. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic block diagram of a frequency diversity and polarization diversity transmission system based on a diversity antenna, provided in an embodiment of the present invention.

[0028] Figure 2 A partial schematic diagram of a frequency diversity and polarization diversity transmission system based on a diversity antenna provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the first diversity antenna provided in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of the second diversity antenna provided in an embodiment of the present invention;

[0031] Figure 5 The amplitude and second phase difference of the first diversity antenna at different positions provided in the embodiments of the present invention;

[0032] Figure 6The amplitude and second phase difference of the second diversity antenna provided in the embodiments of the present invention at different positions.

[0033] The following are the labeling elements in the figure:

[0034] 11-Power divider; 12-Signal phase shifter; 21-First diversity antenna; 210-Strip structure; 211-First strip; 212-Second strip; 213-Third strip; 214-Inductor; 215-Capacitor; 22-Second diversity antenna; 241-First dielectric substrate; 242-Second dielectric substrate; 243-Third dielectric substrate. Detailed Implementation

[0035] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0036] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0037] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] The present invention provides a frequency diversity and polarization diversity transmission system based on diversity antennas. The system includes a diversity antenna subsystem, an RF feed network, and a baseband processing unit. By deploying a first orthogonal polarization diversity antenna 21 and a second orthogonal polarization diversity antenna 22 on both sides of a wireless communication device such as a terminal, and combining them with corresponding signal processing mechanisms, polarization diversity and frequency diversity are achieved in dual frequency bands. The signal processing mechanism equivalently merges horizontal and vertical polarization signals into equivalent left-hand and right-hand circular signals. This signal can significantly enhance the anti-multipath effect during transmission in complex channel environments, improve transmission reliability and data rate, and proposes a novel low-cost antenna RF baseband architecture based on the above technology.

[0040] The frequency diversity and polarization diversity transmission system based on diversity antennas provided in the embodiments of the present invention will now be described.

[0041] Please see Figure 1 Frequency diversity and polarization diversity transmission systems based on diversity antennas include:

[0042] The diversity antenna subsystem includes a first diversity antenna 21, a second diversity antenna 22 and a metal ground plane. Both the first diversity antenna 21 and the second diversity antenna 22 are at least dual-band antennas. The operating frequency bands of the first diversity antenna 21 and the second diversity antenna 22 have at least two overlapping or approximately overlapping frequency bands. The first diversity antenna 21 and the second diversity antenna 22 are spatially orthogonal.

[0043] The radio frequency (RF) feed network includes a signal phase shifter 12, an equivalent phase shifter, a power divider 11, and a signal amplification device. The signal phase shifter 12 is connected to the rear end of the first diversity antenna 21. The equivalent phase shifter is equivalent to the phase center offset generated by the first diversity antenna 21, the second diversity antenna 22, and the metal ground plane. The power divider 11 is used to combine the signal output from the signal phase shifter 12 and the signal output from the second diversity antenna 22. The signal amplification device is used to amplify the signal output from the power divider 11. When the signals of the first diversity antenna 21 and the second diversity antenna 22 at different frequencies are combined by the power divider 11, frequency diversity is achieved. When the signals of the first diversity antenna 21 and the second diversity antenna 22 at the same frequency are combined by the power divider 11, the first polarization diversity (linear polarization isolation, generally horizontal and vertical polarization) is achieved based on the spatial orthogonal arrangement of the first diversity antenna 21 and the second diversity antenna 22, and the second polarization diversity is achieved based on the RF feed network.

[0044] The baseband processing unit is used to receive and process the radio frequency signals output by the power divider 11.

[0045] In the diversity antenna subsystem, both the first diversity antenna 21 and the second diversity antenna 22 are at least dual-band antennas, meaning that the first diversity antenna 21 is a dual-band or multi-band antenna (more than two frequencies), and the second diversity antenna 22 is also a dual-band or multi-band antenna (more than two frequencies). The operating frequency bands of the first diversity antenna 21 and the second diversity antenna 22 overlapping or approximately overlapping at least two means that both the first diversity antenna 21 and the second diversity antenna 22 have multiple operating frequency bands (resonant frequency bands), and at least two operating frequency bands in the first diversity antenna 21 are the same as or approximately the same as at least two operating frequency bands in the second diversity antenna 22. For example, if the first diversity antenna 21 resonates at a first frequency and a second frequency, the second diversity antenna 22 also resonates at the first frequency and a second frequency. The first diversity antenna 21 and the second diversity antenna 22 are spatially orthogonal, meaning that the plane containing the first diversity antenna 21 is perpendicular to the plane containing the second diversity antenna 22.

[0046] In the RF feed network, the signal phase shifter 12 is connected to the rear end of the first diversity antenna 21 to receive the signal from the first diversity antenna 21 and perform phase shifting on the signal to achieve a first phase difference between the first diversity antenna 21 and the second diversity antenna 22. The equivalent phase shifter is a virtual phase shifter. The structure formed by the first diversity antenna 21, the second diversity antenna 22, and the metal ground plane, at the operating frequency, allows the first diversity antenna 21 and the second diversity antenna 22 to receive far-field signals (…). z When electromagnetic waves are emitted in a certain direction, a phase center offset naturally forms between them; this phase center offset can be considered as a second phase difference. The phase center offset is along... z The phase center offset in the direction (focusing only on the three-dimensional coordinates of the phase center). z (The coordinates of the direction), this phase center offset is closely related to the first diversity antenna 21 and the second diversity antenna 22 and their relative positions with the metal ground plane. The second phase difference at two frequencies can be adjusted relatively flexibly by adjusting the positions of the first and second diversity antennas. The physical essence of the second phase difference, i.e., the phase center offset, is that the diversity antenna, as a radiating structure, has a current distribution on both the diversity antenna and the metal ground plane. The radiation formed by this overall current distribution in the far-field space... z The direction can be considered as the radiation source originating at a certain point. This point is called the equivalent phase center. Once the phase position of the diversity antenna and the metal ground, as well as the diversity antenna and other surrounding structural components, changes will cause changes in the overall radiated current distribution, which will also affect the equivalent phase center of the far-field radiation. This phase center offset is generally to be avoided in antenna design to ensure the phase stability of the radiation. However, this invention innovatively utilizes this phase center offset as a second phase difference, thus cleverly realizing the simultaneous synthesis of dual-frequency signals into equivalent left-hand and right-hand polarized signals.

[0047] The power divider 11 combines the signal output from the signal phase shifter 12 and the signal output from the second diversity antenna 22. The signal amplification device receives the signal output from the power divider 11 and amplifies it. It should be noted that in practical applications, the first diversity antenna 21 and the second diversity antenna 22 will generate phase shifts on their transmission links. However, this invention focuses on the relative phase shift between the first diversity antenna 21 and the second diversity antenna 22. Therefore, the signal phase shifter 12 and the equivalent phase shifter are both considered to be on the transmission link of the first diversity antenna 21. Without the signal phase shifter 12 and the equivalent phase shifter, the phase shift from the first diversity antenna 21 to the power divider 11 and the phase shift from the second diversity antenna 22 to the power divider 11 are the same.

[0048] When receiving signals, the signal from the first diversity antenna 21, after passing through the signal phase shifter 12 and the equivalent phase shifter, is combined with the signal transmitted by the second diversity antenna 22 through the power divider 11. Then, after being amplified by the signal amplification device, it is received and processed by the baseband processing unit. The transmission and reception processes of the transmission system are reciprocal. Correspondingly, the baseband processing unit also emits radio frequency signals, which, after passing through the signal amplification device and the power divider 11, and undergoing phase shifting via the signal phase shifter 12 and the equivalent phase shifter, are radiated outwards by the first diversity antenna 21 and the second diversity antenna 22.

[0049] When the first diversity antenna 21 and the second diversity antenna 22 combine signals of different frequencies, frequency diversity is achieved due to their different operating frequencies, thus realizing the first layer of isolation optimization. Since the first diversity antenna 21 and the second diversity antenna 22 are spatially orthogonal, even when they operate at the same frequency, their polarization modes are different, achieving the first polarization diversity and reaching the second layer of isolation (the first polarization diversity is achieved through the spatially orthogonal placement of the first diversity antenna 21 and the second diversity antenna 22, typically horizontal and vertical polarization). After passing through the RF feed network (the relative phase shift formed by the signal phase shifter 12 and the equivalent phase shifter), the first diversity antenna 21 and the second diversity antenna 22 can be equivalently considered as signals of different frequencies forming another polarization diversity after signal processing (the second polarization diversity, i.e., equivalent left-hand circular polarized signal and equivalent right-hand circular polarized signal). Therefore, the transmission system at this time can achieve coordinated diversity of frequency diversity and polarization diversity. Because of the superposition of the two diversity signals, the two signals achieve an isolation of at least -140dB when they reach the power divider 11. Therefore, when the synthesized signal passes through the signal amplification device, it does not need to be split to amplify the different frequency signals. The two signals have already achieved dual diversity through the signal processing of the RF feed network, achieving a very ideal isolation. No further split amplification or filtering is required. Conventional split amplification requires an additional amplifier, and conventional filtering requires at least one filter or low-noise amplifier.

[0050] The frequency diversity and polarization diversity transmission system based on diversity antennas in the above embodiments includes a diversity antenna subsystem, an RF feed network, and a baseband processing unit. The diversity antenna subsystem includes a first diversity antenna 21 and a second diversity antenna 22. The first diversity antenna 21 and the second diversity antenna 22 achieve frequency diversity when signals at different frequencies are combined. The first diversity antenna 21 and the second diversity antenna 22 are spatially orthogonal, so that the two diversity antennas achieve the first polarization diversity when signals at the same frequency are combined. After passing through the signal phase shifter 12 and the equivalent phase shifter, the first diversity antenna 21 and the second diversity antenna 22 achieve the second polarization diversity when signals at the same frequency are combined. Through the collaborative innovation of the RF front-end and the baseband processing, a complete RF baseband architecture capable of simultaneously and actively achieving coordinated processing of polarization diversity and frequency diversity is constructed. This architectural innovation is expected to achieve significantly better anti-multipath performance, higher link reliability, and greater system throughput under the same antenna element conditions, bringing a breakthrough improvement to the performance of terminal satellite communication. At the same time, it can reduce the number of components in the signal amplification device while ensuring dual diversity collaborative operation, thereby minimizing the complexity of the system and the cost of the RF link.

[0051] In some embodiments of the present invention, please refer to Figure 1Under the influence of the signal phase shifter 12, the first diversity antenna 21 and the second diversity antenna 22 produce a relative phase shift at the first frequency. a 1. The first diversity antenna 21 and the second diversity antenna 22 generate a relative phase shift at the second frequency. a 2, The relative displacement is inversely proportional to the frequency. Under the influence of the equivalent phase shifter, the first diversity antenna 21 and the second diversity antenna 22 produce a relative phase shift at the first frequency. b 1. The first diversity antenna 21 and the second diversity antenna 22 generate a relative phase shift at the second frequency. b 2, b 1 and b 2. Mutual decoupling. Mutual decoupling refers to... b 1 and b 2. They are unrelated or have very little correlation. The first frequency and the second frequency are different resonant frequencies.

[0052] The signal phase shifter 12 can generally be implemented using structures such as microstrip lines. In the transmission links of the first diversity antenna 21 and the second diversity antenna 22, the length difference of the microstrip lines of the two transmission links is fixed. Therefore, the phase shift generated at a certain frequency is also fixed, and the functional relationship between the phase shifts generated at different frequencies is determined. a 1 and a 2. It is impossible for both to be 90 degrees simultaneously. The equivalent phase shifter produces phase shifts at the first and second frequencies, respectively. b 1 and b 2 will not affect each other. Therefore, by working together with the signal phase shifter 12 and the equivalent phase shifter, the relative phase shift at the first frequency can be 90 degrees or close to 90 degrees (hereinafter referred to as 90 degrees for ease of description), and the relative phase shift at the second frequency can be -90 degrees or close to -90 degrees (hereinafter referred to as -90 degrees for ease of description), thereby achieving the second polarization diversity (equivalent left-handed polarized signal and equivalent right-handed polarized signal).

[0053] To ensure that the relative phase offset between the first diversity antenna 21 and the second diversity antenna 22 is 90 degrees at the first frequency and -90 degrees at the second frequency, adjustments are required. a 1. a 2. b 1 and b 2, a 1 and a The change in 2 is achieved by adjusting the length difference of the microstrip lines mentioned above. b 1 and b The change in 2 can be achieved by adjusting the positions of the first diversity antenna 21 and the second diversity antenna 22. For details, please refer to [link / reference needed]. Figure 3and Figure 4 The first diversity antenna 21 in the first direction x The position above is the first position, and the second diversity antenna 22 is in the second direction. y The position above is the second position; the change is achieved by adjusting the first and second positions. b 1 and b 2. The intersection line of the planes containing the first diversity antenna 21 and the second diversity antenna 22 is the first reference line, and the distance between the first diversity antenna 21 and the first reference line is denoted as Δ. x Adjusting the first position can be understood as adjusting Δ x ( x (axial displacement); the distance between the second diversity antenna 22 and the first reference line is Δ y Adjusting the second position can be understood as adjusting Δ y ( y Axial displacement).

[0054] To further illustrate that the transmission system of the present invention can perform second polarization diversity, Figure 2 A physical prototype of the transmission system was fabricated and subjected to a series of actual tests and simulations. The first diversity antenna 21 and the second diversity antenna 22 have the same structural shape. The key dimensions of the diversity antennas are as follows: the first frequency is 1.575 GHz, and the second frequency is 3.8 GHz; the width of the strips in both the first diversity antenna 21 and the second diversity antenna 22 is 0.5 mm; in the first diversity antenna 21, the length of the first strip 211 is 15.3 mm, the length of the second strip 212 is 19.6 mm, the length of the third strip 213 is 4.9 mm, and the height is 2 mm; in the second diversity antenna 22, the length of the first strip 211 is 20.5 mm, the length of the second strip 212 is 9.6 mm, the length of the third strip 213 is 9.7 mm, and the height is 2 mm.

[0055] Figure 5 The amplitude and second phase difference of the first diversity antenna 21 at different positions. Figure 6 This represents the amplitude and second phase difference of the second diversity antenna 22 at different positions. According to... Figure 5 and Figure 6 It can be seen that at 1.575 GHz, with the first position Δ x ( x (axial displacement) and second position Δ y ( y The change in axial displacement, amplitude, and second phase difference is not significant. At 3.8 GHz, the antenna changes little with the change in the first position Δ x The changes in amplitude and second phase difference are significant, with the second position Δ... yThe amplitude of the change remains basically unchanged, while the second phase difference changes more significantly. Therefore, at the first frequency, when the amplitudes of the first diversity antenna 21 and the second diversity antenna 22 are approximately equal and the relative phase shift is approximately 90 degrees, the first position Δ can be adjusted. x Second position Δ y To adjust the relative phase shift at the second frequency, so that the relative phase shift at the second frequency is approximately -90 degrees.

[0056] Based on the above findings, and considering the combined effects of the first phase difference introduced by the signal phase shifter 12 and the phase center difference (second phase difference) of the diversity antenna, for the 1.575 GHz frequency point where the displacement effect is relatively small, the first phase difference should be prioritized in the design. a 1 = 75.6°; For the 3.8 GHz frequency point, set the first phase difference. a 2 = 182.2°. b 1 and b 2 are respectively b 1 = 14.4° and b 2 = 87.8°. Therefore... a 1+ b 1 = 90° a 2+ b 2 = 270 (i.e., -90 phase difference), thus achieving the second polarization diversity. According to... Figure 5 and Figure 6 As shown, the displacements required for the second polarization diversity are Δx = 3 mm and Δy = 0 mm.

[0057] In some embodiments of the present invention, the signal received by the first diversity antenna 21, after passing through the signal phase shifter 12 and the equivalent phase shifter, is the first signal. E 1. The signal received by the second diversity antenna 22 is the second signal. E 2, First signal E 1 includes a first component signal at a first frequency and a second component signal at a second frequency, the second signal... E 2 includes the third component signal at the first frequency and the fourth component signal at the second frequency, and the phase difference between the first and third component signals ( a 1+ b 1) For The phase difference between the second and fourth sub-signals ( a 2+ b 2) for ,in, n The value is an integer. During the combining process by power divider 11, the first and third signals at the first frequency are combined, and the second and fourth signals at the second frequency are combined. The phase difference of the diversity antenna at the first frequency ( a 1+ b1) For The phase difference of the diversity antenna at the second frequency ( a 2+ b 2) for .

[0058] In some embodiments of the present invention, the power divider 11 receives the combining signal. ,

[0059] ,

[0060] ,but

[0061] ,

[0062] That is, the first and third sub-signals are combined to form a right-hand circularly polarized signal, and the second and fourth sub-signals are combined to form a left-hand circularly polarized signal, so as to achieve the second polarization diversity.

[0063] in, ω 1 and the first frequency f 1 corresponds to ( ω 1=2 πf 1), ω 2 and the second frequency f 2 correspondences ( ω 2=2 πf 2) A 1 represents the amplitude of the first diversity antenna 21 at the first frequency. A 2 represents the amplitude of the first diversity antenna 21 at the second frequency. B 1 represents the amplitude of the second diversity antenna 22 at the first frequency. B 2 represents the amplitude of the second diversity antenna 22 at the second frequency. A 1≈ B 1, A 2≈ B 2; a The phase shift generated by the second diversity antenna 22 to the power divider 11 at the first frequency. b The phase shift generated by the second diversity antenna 22 to the power divider 11 at the second frequency.

[0064] Thus, based on the orthogonal isolation of the naturally polarized signals (left-hand and right-hand circular), a third layer of isolation is achieved during signal synthesis and processing. Furthermore, through signal processing, it can be equivalently viewed that signals of different frequencies form a second polarization diversity after processing (unlike the first polarization diversity, which is horizontal and vertical polarization determined by antenna placement; now, based on signal reception processing, left-hand and right-hand circular polarization is formed). In addition, since the first and second frequencies are different, frequency diversity exists. Therefore, the transmission system can achieve coordinated frequency diversity and polarization diversity. It is precisely because of the superposition of these two diversity signals that the two signals of the transmission system achieve at least -140dB of isolation when they reach the power divider 11.

[0065] In some embodiments of the present invention, please refer to Figure 1 The baseband processing unit includes a first chip and a second chip. The first chip receives signals at a first frequency, and the second chip receives signals at a second frequency. The signal amplification device can be one of the following two types:

[0066] In one embodiment, the signal amplification device includes a signal amplifier that receives signals of a first frequency and a second frequency, and transmits the first frequency signal to a first chip and the second frequency signal to a second chip. Due to the aforementioned triple isolation, the two signals synthesized by the power divider 11 do not need to be amplified separately at different frequencies when passing through the signal amplifier. This is because the two signals have already achieved dual polarization diversity through the RF feed network, achieving a very high degree of isolation. Therefore, the two signals do not require further amplification or filtering. Conventional signal amplification requires adding a signal amplifier, and conventional filtering requires at least one filter or low-noise amplifier.

[0067] In another embodiment, the signal amplification device includes two signal amplifiers. One signal amplifier receives a signal of a first frequency and transmits it to a first chip, while the other signal amplifier receives a signal of a second frequency and transmits it to a second chip. This embodiment amplifies signals of different frequencies separately using different signal amplifiers, requiring a relatively large number of signal processors.

[0068] In some embodiments of the present invention, both the first diversity antenna 21 and the second diversity antenna 22 are dual-band antennas, with a first frequency of 1.5 GHz to 1.6 GHz and a second frequency of 3.7 GHz to 3.9 GHz. The first and second frequencies are commonly used resonant frequencies of the terminal.

[0069] It should be noted that the main inventive point of this invention lies in improving the radio frequency architecture to achieve frequency diversity and dual-polarization diversity. The specific structures of the first diversity antenna 21 and the second diversity antenna 22 are not limited here. The present invention provides at least one structural form of diversity antenna in the following content for reference, which does not constitute a limitation of the present invention. Other forms of diversity antennas may also be used.

[0070] In some embodiments of the present invention, please refer to Figure 2 The first diversity antenna 21 and the second diversity antenna 22 have the same structure, which means that the two diversity antennas have the same shape, making it easier to achieve the first polarization diversity.

[0071] In some embodiments of the present invention, please refer to Figures 2 to 4 The first diversity antenna 21 includes two symmetrically arranged strip structures 210. One strip structure 210 is connected to the signal phase shifter 12, and the other strip structure 210 is connected to a metal ground plane. The two strip structures 210 are identical in shape and size. One strip structure 210 is connected to the signal phase shifter 12 for transmitting signals to the signal phase shifter 12, and the other strip structure 210 is connected to the metal ground plane for grounding. Both the first diversity antenna 21 and the second diversity antenna 22 can be dipole antennas.

[0072] In some embodiments of the present invention, please refer to Figure 3 and Figure 4 The strip structure 210 is equipped with tuning devices for adjusting the first and second frequencies. These tuning devices include a capacitor 215 and / or an inductor 214. The tuning devices are used to adjust the first and second frequencies. Specifically, after the structural design of the first diversity antenna 21 and the second diversity antenna 22 is completed, it is difficult for the two resonant frequencies of the diversity antenna to directly and simultaneously meet the preset first and second frequencies. Therefore, it is necessary to set up tuning devices to ensure that the two resonant frequencies of the diversity antenna meet the communication requirements. The tuning device can be a capacitor 215, an inductor 214, or a combination of both. In related technologies, the frequency of the first diversity antenna 21 and the second diversity antenna 22 is generally adjusted by changing the electrical length. However, this frequency modulation method causes both resonant frequencies to be adjusted simultaneously, making independent adjustment of a single frequency point impossible. Therefore, it is impossible for both resonant frequencies to simultaneously meet the target resonant frequency. To address this, the present invention introduces the mode compression principle, loading an inductor 214 and a capacitor 215 onto the dipole stub, thereby achieving independent control of the resonant frequencies of different modes.

[0073] In some embodiments of the present invention, please refer to Figure 3 and Figure 4The strip structure 210 includes a first strip 211, a second strip 212, and a third strip 213 connected in sequence. The end of the third strip 213 away from the second strip 212 is connected to the signal phase shifter 12 or a metal ground plane. The first strip 211 and the second strip 212 are connected by an inductor 214, and the second strip 212 and the third strip 213 are connected by a capacitor 215. When the strip structure 210 is connected to the signal phase shifter 12, the third strip 213 of the strip structure 210 is also connected to the signal phase shifter 12. When the strip structure 210 is connected to the metal ground plane, the third strip 213 of the strip structure 210 is also connected to the metal ground plane.

[0074] In some embodiments of the present invention, please refer to Figure 3 and Figure 4 The capacitor 215 is positioned near the maximum current value of the first diversity antenna 21, and the inductor 214 is positioned near the minimum current value of the first diversity antenna 21. The capacitor 215 can be located at the position of the maximum current value of the first diversity antenna 21, and the inductor 214 can be located at the position of the minimum current value of the first diversity antenna 21.

[0075] In some embodiments of the present invention, please refer to Figure 3 and Figure 4 The third strip 213 is bent, with a portion extending along the first direction and another portion extending along the third direction. The third strip 213 is L-shaped; the portion of the third strip 213 extending along the first direction means that the length direction of this portion is perpendicular to the first direction. x The direction is parallel, and the other part of the third strip 213 extends along the third direction, which means that the length direction of the third strip 213 part is parallel to the direction of the third strip 213. z The directions are parallel. The above describes the extension direction of the third strip 213 of the first diversity antenna 21. In the second diversity antenna 22, the shape of the third strip 213 is similar to that of the strip in the first diversity antenna 21, only the extension direction is different. Specifically, in the second direction, part of the third strip 213 extends along... y Extending in one direction, the other part along z directional extension.

[0076] By bending the third strip 213, the first diversity antenna 21 and the second diversity antenna 22 are made into folded diversity antennas, which can further miniaturize the first diversity antenna 21 and the second diversity antenna 22, reduce the space occupied, and make them more suitable for terminal antennas.

[0077] In some embodiments of the present invention, please refer to Figure 2The frequency diversity and polarization diversity transmission system based on diversity antennas also includes a first dielectric substrate 241, a second dielectric substrate 242, and a third dielectric substrate 243 arranged orthogonally in pairs. A signal phase shifter 12 and a power divider 11 are disposed on one side of the first dielectric substrate 241 in the thickness direction, and a metal ground plane is disposed on the other side of the first dielectric substrate 241 in the thickness direction. A first diversity antenna 21 is disposed on the second dielectric substrate 242, and a second diversity antenna 22 is disposed on the third dielectric substrate 243. The first dielectric substrate 241, the second dielectric substrate 242, and the third dielectric substrate 243 are all made of non-conductive material, such as FR-4. The opposite sides of the first dielectric substrate 241 are located on its thickness direction (…). z The signal phase shifter 12, the first diversity antenna 21, and the second diversity antenna 22 are all made of conductive materials, such as copper. The first dielectric substrate 241 and... xoy Planar parallel, the second dielectric plate 242 and xoz Planar parallel, third dielectric plate 243 and yoz Planes are parallel.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A frequency diversity and polarization diversity transmission system based on a diversity antenna, characterized in that, include: The diversity antenna subsystem includes a first diversity antenna, a second diversity antenna, and a metal ground plane. Both the first diversity antenna and the second diversity antenna are at least dual-band antennas. The operating frequency bands of the first diversity antenna and the second diversity antenna have at least two overlapping or approximately overlapping frequency bands. The first diversity antenna and the second diversity antenna are spatially orthogonal. The radio frequency feed network includes a signal phase shifter, an equivalent phase shifter, a power divider, and a signal amplification device. The signal phase shifter is connected to the rear end of the first diversity antenna. The equivalent phase shifter is formed by the phase center offset generated by the first diversity antenna, the second diversity antenna, and the metal ground plane. The power divider is used to combine the signal output from the signal phase shifter and the signal output from the second diversity antenna. The signal amplification device is used to amplify the signal output from the power divider. Frequency diversity is achieved when signals from the first diversity antenna and the second diversity antenna at different frequencies are combined by the power divider; when signals from the first diversity antenna and the second diversity antenna at the same frequency are combined by the power divider, first polarization diversity is achieved based on the spatial orthogonal arrangement of the first diversity antenna and the second diversity antenna, and second polarization diversity is achieved based on the radio frequency feed network. The baseband processing unit is used to receive and process the radio frequency signal output by the signal amplification device.

2. The frequency diversity and polarization diversity transmission system based on diversity antennas as described in claim 1, characterized in that, Under the influence of the signal phase shifter, the first diversity antenna and the second diversity antenna produce a relative phase shift at the first frequency. a 1. The first diversity antenna and the second diversity antenna generate a relative phase shift at the second frequency. a 2, , ω 1=2 πf 1, ω 2=2 πf 2, f 1 represents the first frequency. f 2 represents the second frequency; under the influence of the equivalent phase shifter, the first diversity antenna and the second diversity antenna experience a relative phase shift at the first frequency. b 1. The first diversity antenna and the second diversity antenna produce a relative phase shift at the second frequency. b 2, b 1 and b 2. Mutual decoupling.

3. The frequency diversity and polarization diversity transmission system based on diversity antennas as described in claim 2, characterized in that, The signal received by the first diversity antenna, after passing through the signal phase shifter and the equivalent phase shifter, becomes the first signal. E 1. The signal received by the second diversity antenna is the second signal. E 2, the first signal E 1 includes a first component signal at a first frequency and a second component signal at a second frequency, the second signal... E 2 includes a third component signal at the first frequency and a fourth component signal at the second frequency, wherein the phase difference between the first component signal and the third component signal is ( a 1+ b 1) For The phase difference between the second sub-signal and the fourth sub-signal ( a 2+ b 2) for ,in, n It is an integer.

4. The frequency diversity and polarization diversity transmission system based on diversity antennas as described in claim 3, characterized in that, The power divider receives the combining signal , ， ,but ， That is, the first sub-signal and the third sub-signal are combined to form a right-hand circularly polarized signal, and the second sub-signal and the fourth sub-signal are combined to form a left-hand circularly polarized signal, so as to achieve the second polarization diversity; in, ω 1 corresponds to the first frequency. ω 2 corresponds to the second frequency. A 1 represents the amplitude of the first diversity antenna at the first frequency. A 2 represents the amplitude of the first diversity antenna at the second frequency. B 1 represents the amplitude of the second diversity antenna at the first frequency. B 2 represents the amplitude of the second diversity antenna at the second frequency. A 1≈ B 1, A 2≈ B 2; a The phase shift generated by the second diversity antenna to the power divider at the first frequency. b The phase shift generated by the second diversity antenna to the power divider at the second frequency.

5. The frequency diversity and polarization diversity transmission system based on diversity antennas as described in claim 4, characterized in that, The baseband processing unit includes a first chip and a second chip; The signal amplification device includes a signal amplifier that receives signals of the first frequency and the second frequency, and transmits the signal of the first frequency to the first chip and the signal of the second frequency to the second chip; or... The signal amplification device includes two signal amplifiers, one of which receives a signal of a first frequency and transmits the signal of the first frequency to the first chip, and the other of which receives a signal of a second frequency and transmits the signal of the second frequency to the second chip.

6. The frequency diversity and polarization diversity transmission system based on diversity antennas as described in any one of claims 2-4, characterized in that, The first frequency is 1.5 GHz to 1.6 GHz, and the second frequency is 3.7 GHz to 3.9 GHz.

7. The frequency diversity and polarization diversity transmission system based on diversity antennas as described in any one of claims 1-4, characterized in that, The first diversity antenna and the second diversity antenna have the same structure.

8. The frequency diversity and polarization diversity transmission system based on a diversity antenna as described in any one of claims 2-4, characterized in that, The first diversity antenna includes two symmetrically arranged strip structures, one of which is connected to the signal phase shifter, and the other of which is connected to the metal ground plane.

9. The frequency diversity and polarization diversity transmission system based on diversity antennas as described in claim 8, characterized in that, The strip structure is provided with tuning devices for adjusting the first frequency and the second frequency, and the tuning devices include capacitors and / or inductors.

10. The frequency diversity and polarization diversity transmission system based on a diversity antenna as described in any one of claims 1-4, characterized in that, It also includes a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate arranged orthogonally in pairs. The signal phase shifter and the power divider are disposed on one side of the first dielectric substrate in the thickness direction, the metal ground plane is disposed on the other side of the first dielectric substrate in the thickness direction, the first diversity antenna is disposed on the second dielectric substrate, and the second diversity antenna is disposed on the third dielectric substrate.

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