Miniaturized four-frequency active navigation antenna with high phase center stability

Abstract

The invention discloses a miniaturized four-frequency active navigation antenna with high phase center stability. The miniaturized four-frequency active navigation antenna is composed of a structure mounting platform, a feed network layer, a low noise amplifier circuit layer and a passive antenna. According to the miniaturized four-frequency active navigation antenna with the high phase center stability, the high phase center stability can be ensured on the premise of four-frequency working; the higher the stability of the antenna phase center is, the higher the positioning precision is; each working frequency band adopts double-feed to realize circular polarization, so that the problem of low stability of a phase center caused by multi-frequency design of the antenna is solved, and multi-frequency-band high-precision positioning is realized; the dielectric materials in charge of each working frequency band are selected from the same material, so that the cost is saved; miniaturization processing is adopted, and B3 frequency band miniaturization is realized by using an SRR structure and a T-shaped branch knot; the information receiving and transmitting system of the active navigation antenna is provided, and a laminated composite fixing mode which is high in integration level and does not affect radiation performance is achieved.

Description

Technical Field

[0001] The invention relates to the field of antennas, and in particular to a miniaturized quad-frequency active navigation antenna with high phase center stability. Background Art

[0002] In satellite communication and navigation systems, antennas, as devices for receiving and transmitting electromagnetic waves, are one of the most important components. The performance of antennas directly determines the positioning accuracy and functional diversity of the navigation system.

[0003] The existing global satellite navigation systems include the United States' GPS, Russia's GLONASS, the European Union's Galileo and China's independently developed BeiDou satellite navigation system. Since the four major satellite navigation systems have their own advantages and disadvantages in terms of positioning accuracy, coverage, security and reliability, integrating multiple navigation frequency bands on the terminal can give full play to the advantages of each system and improve the navigation performance of the receiver terminal. Therefore, it is necessary to use antennas with multi-band performance.

[0004] At present, the mainstream antenna types mainly include four-arm spiral antennas, microstrip antennas, and vibrator antennas. When the design space is small, microstrip antennas are widely used due to their low profile and easy conformal characteristics. The design forms of microstrip antennas are mainly divided into the following categories: For conventional navigation systems, the system is limited by the application space, and the antenna is usually designed to work in dual-band / triple-band mode. There is still room for expansion of the system's frequency band diversity, and the common multi-frequency design on the market is to reduce the difficulty of feeding design brought by multiple frequency bands. Usually, some of the working frequency bands are designed as single-fed circular polarization, and the remaining frequency bands are dual-fed circular polarization to ensure the basic positioning accuracy requirements of the system. The more circular polarization feeds the antenna has, the better. The better the stability of its phase center, the better the antenna phase center stability directly affects the positioning accuracy of the system. Therefore, there is room for improvement in the phase center stability of multi-frequency antennas. In order to achieve miniaturization performance, microstrip antennas generally use a variety of high dielectric constant substrates in combination, which will inevitably increase the antenna cost and reduce the antenna gain. The use of low dielectric constant substrates will make the antenna insufficiently miniaturized. In terms of antenna fixing methods, due to the bandwidth limitations of microstrip antennas, multi-layer radiation patches are generally used to achieve multi-frequency performance. How to ensure the firmness of the antenna structure in a simple and easy-to-implement way without affecting the electrical performance is also an important issue that needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to propose a miniaturized quad-band active navigation antenna with high phase center stability, in view of the technical problems of existing Beidou navigation antennas, such as the need to improve the frequency band diversity, low phase center stability, high cost, insufficient miniaturization and complex installation. While ensuring the simultaneous reception of quad-band signals from Beidou and GPS, the present invention has the advantages of miniaturization, low cost, low profile, high integration and phase center stability, and can meet the needs of multi-system and multi-service satellite communication.

[0006] A miniaturized quad-band active navigation antenna with high phase center stability, consisting of a structural mounting platform, a feed network layer, a low noise amplifier circuit layer, and a passive antenna; The passive antenna, the structural installation platform, the feed network layer, and the low-noise amplifier circuit layer are arranged sequentially from top to bottom, the passive antenna, the feed network layer, and the low-noise amplifier circuit layer are fixed by conductive glue, the countersunk screws sequentially pass through the four symmetrical positions of the passive antenna, the structural installation platform, the feed network layer, and the low-noise amplifier circuit layer to be fixed with nuts, and the pan head screws sequentially pass through the passive antenna, the structural installation platform, the feed network layer, and the low-noise amplifier circuit layer to be fixed with nuts; The passive antenna is composed of four layers of the same dielectric substrate stacked together, the cross-sectional area of ​​the dielectric substrate of the upper layer is smaller than the cross-sectional area of ​​the dielectric substrate of the lower layer, a radiation patch is attached on the upper side of the dielectric substrate, a copper foil is covered on the lower side of the dielectric substrate, and symmetrical debugging branches are arranged around the radiation patch; The two feeding pads of the radiation patch are located as feeding points, and the feeding points are in a dual feeding form; The structural installation platform is circular or square in shape; A threaded via is provided at the center of the quad-band active navigation antenna, and metal vias are provided at the four corners of the passive antenna, the structural mounting platform, the feed network layer, and the low noise amplifier circuit layer; The metal vias are located at the four corners of the structural installation platform, the feed network layer, and the low noise amplifier circuit layer; The feed network layer includes an orthogonal hybrid network circuit and a combined output feed pad; The orthogonal hybrid network circuit combines and outputs satellite signals, and the combined signals are output to the low noise amplifier circuit layer through the metal probe; The low noise amplifier circuit includes four frequency bands of burn-out resistant active low noise amplifier filter circuits; The anti-burning active low-noise amplification and filtering circuit comprises a pre-selection filter, a limiter, a low-noise amplifier, a band-pass filter, and a power supply circuit; The pre-selection filter filters the combined signal; The limiter limits the high-power signal in-band or out-of-band; The low noise amplifier performs low noise amplification on the satellite signal; The bandpass filter suppresses near-end interference signals; The power supply circuit outputs satellite signals and inputs external direct current power.

[0007] Furthermore, a miniaturized quad-frequency active navigation antenna with high phase center stability is provided, wherein the dielectric substrate comprises a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, and a fourth dielectric substrate; The dielectric substrate is chamfered on all sides, and the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, and the fourth dielectric substrate are aligned along the geometric center points of the dielectric substrates and stacked from top to bottom; The radiation patches include a band S radiation patch, a band GPS / B1 radiation patch, a band B3 radiation patch, and a band B2b radiation patch; The radiation patch of the next layer serves as the metal ground of the radiation patch of the previous layer, generating resonance in the working frequency band of the radiation patch; The middle part of the radiation patch is a square, and one corner of an isosceles right triangle is cut off from the four corners of the radiation patch. The cut corner changes the current phase of the radiation patch in the direction of two feeding points.

[0008] Furthermore, a miniaturized quad-frequency active navigation antenna with high phase center stability is provided, wherein the feeding point comprises four pairs of feeding points, and the four pairs of feeding points are placed along four directions at 90° rotation intervals, namely a first feeding point, a second feeding point, a third feeding point, and a fourth feeding point; The first feeding point is the two feeding pads of the band S radiation patch, the second feeding point is the two feeding pads of the band GPS / B1 radiation patch, the third feeding point is the two feeding pads of the band B3 radiation patch, and the fourth feeding point is the two feeding pads of the band B2b radiation patch; The feeding point, the second feeding point, the third feeding point and the fourth feeding point are placed through different metal probes, the tops of the different metal probes are respectively connected to the feeding point, the second feeding point, the third feeding point and the fourth feeding point pads, the bottoms of the metal probes pass through the structural mounting platform and are welded to the feeding network layer, and the metal probes achieve 0° and 90° dual feed phase differences through the feeding network layer.

[0009] Furthermore, a miniaturized quad-band active navigation antenna with high phase center stability, the debugging branches include a first square debugging branch, a second square debugging branch, a first T-shaped debugging branch, and a second T-shaped debugging branch; The frequency band S radiation patch is provided with a first square debugging branch which is symmetrical on all sides, and the frequency band B2b radiation patch is provided with a second square debugging branch which is symmetrical on all sides; The resonant point movement of the band S radiation patch and the band B2b radiation patch is controlled by the length of the square debugging branch; The frequency band GPS / B1 radiation patch is provided with a first T-shaped debugging branch which is symmetrical all around, and the frequency band B3 radiation patch is provided with a second T-shaped debugging branch which is symmetrical all around; The resonance point movement of the frequency band GPS / B1 radiation patch and the frequency band B3 radiation patch is achieved by adjusting the length of the T-shaped adjustment branch.

[0010] Further, a miniaturized quad-band active navigation antenna with high phase center stability, the band B3 radiation patch further includes but is not limited to an SRR slot structure; The SRR gap structure consists of two C-shaped or square rings that are open and nested with each other; The SRR slot structure further includes but is not limited to increasing an equivalent current path of the antenna, and the equivalent current path suppresses higher-order modes of the antenna.

[0011] Furthermore, a miniaturized quad-band active navigation antenna with high phase center stability is provided, wherein there are four orthogonal hybrid network circuits, each of which is rotated 90° and placed in four directions to combine and output four pairs of 0° and 90° satellite signals from four frequency bands respectively; The combined output feed pads include an S-band combined output feed pad, a GPS / B1-band combined output feed pad, a B3-band combined output feed pad, and a B2b-band combined output feed pad.

[0012] Furthermore, a miniaturized quad-band active navigation antenna with high phase center stability is provided, wherein the material of the dielectric substrate includes ceramic and polyphenylene ether resin, the dielectric constant of the dielectric substrate is 10.2, and the thickness of the dielectric substrate is 4 mm; The structural mounting platform is made of aluminum; The feed network layer and the low noise amplifier circuit layer are copper-clad double-layer boards, and the dielectric substrate includes a flame-retardant copper-clad epoxy glass fiber cloth laminate and a bonding sheet; The thickness of the dielectric substrate is 1.5 mm, and the dielectric constant of the dielectric substrate is 4.2; The size of the first dielectric substrate is 25mm*25mm, the size of the second dielectric substrate is 31mm*31mm, the size of the third dielectric substrate is 39mm*39mm, and the size of the fourth dielectric substrate is 50mm*50mm; The side length of the middle part of the band S radiation patch is 18.5 mm, the side length of the middle part of the band GPS / B1 radiation patch is 28.5 mm, the side length of the middle part of the band B3 radiation patch is 35.5 mm, and the side length of the middle part of the band B2b radiation patch is 43 mm; The radius of the feeding point is 1 mm; The diameters of the S-band combined output feed pad, the GPS / B1-band combined output feed pad, the B3-band combined output feed pad, and the B2b-band combined output feed pad are 1 mm, and the through-hole diameter of the pad is 0.4 mm; The metal via radii are 1 mm and 0.4 mm; The threaded through hole has a diameter of 2.3 mm.

[0013] Furthermore, in a miniaturized quad-band active navigation antenna with high phase center stability, the working principle of the burn-resistant active low-noise amplification and filtering circuit is as follows: The combined input signal of the feed network layer is filtered in the pre-selection filter to suppress the far-end interference signal; The filter outputs the filtered combined signal to the limiter, and the limiter limits the existing in-band or out-of-band high-power signal; The limiter outputs the limited signal to the low noise amplifier for low noise amplification to reduce the link noise figure; The low noise amplifier outputs the noise-amplified satellite signal to the bandpass filter to suppress the near-end interference signal; The bandpass filter outputs the satellite signal that has been limited, amplified and filtered to the power supply circuit, and the power supply circuit outputs the satellite signal; The power supply circuit is an output / input path for satellite signals and external DC power supply.

[0014] Furthermore, a miniaturized four-band active navigation antenna with high phase center stability also includes an information receiving and transmission system for the active navigation antenna. The information receiving and transmission system for the active navigation antenna saves placement area by overlapping the modules and making the feeding network layer independent. The four-band passive antenna is welded to the feeding network layer through the structural mounting platform. The signals of each working frequency band form complete circularly polarized signals through the feeding network layer and are transmitted to the low-noise amplifier circuit layer. The signals are processed by limiting, filtering, and amplifying the low-noise amplifier circuit layer and output to the connector.

[0015] The beneficial effects of the present invention are as follows: through a miniaturized four-frequency active navigation antenna with high phase center stability, high phase center stability can be guaranteed under the premise of four-frequency operation; the higher the stability of the antenna phase center, the higher the positioning accuracy; each working frequency band adopts dual feed to achieve circular polarization, which solves the problem of low phase center stability caused by the multi-frequency design of the antenna and realizes multi-frequency high-precision positioning; the dielectric materials responsible for each working frequency band are selected from the same material to save costs; miniaturization processing is adopted, and SRR structure and T-shaped branches are used to realize miniaturization of B3 frequency band; an information receiving and transmission system for an active navigation antenna is provided, which realizes a stacked composite fixing method with high integration and no influence on radiation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is an exploded view of the antenna of the present invention; Figure 2 is a top view of the antenna of the present invention; Figure 3 is a side view of the antenna of the present invention; Figure 4 It is a schematic diagram of the composition of the feeding network layer of the antenna of the present invention; Figure 5 It is a schematic diagram of the receiving circuit principle of the low noise amplifier circuit layer of the antenna of the present invention; Figure 6 is a schematic diagram of a signal transmission system of the antenna of the present invention; Figure 7 is a schematic diagram of the reflection coefficient of the antenna of the present invention; Figure 8 It is the gain pattern of the antenna of the present invention.

[0017] In the figure, 1-structure mounting platform, 2-countersunk screws, 3-pan head screws, 4-nuts, 7-feed network layer, 8-low noise amplifier circuit layer, 9-passive antenna; In the figure, 21-feeding point, 22-second feeding point, 23-third feeding point, 24-fourth feeding point, 70-orthogonal hybrid network circuit, 71-S band combiner output feed pad, 72-GPS / B1 band combiner output feed pad, 73-B3 band combiner output feed pad, 74-B2b band combiner output feed pad; In the figure, 101-the first square debugging branch, 401-the second square debugging branch, 201-the first T-shaped debugging branch, 301-the second T-shaped debugging branch, 102-band S radiation patch, 202-band GPS / B1 radiation patch, 302-band B3 radiation patch, 402-band B2b radiation patch, 103-the first layer of dielectric substrate, 203-the second layer of dielectric substrate, 303-the third layer of dielectric substrate, 403-the fourth layer of dielectric substrate, 304-SRR gap structure. DETAILED DESCRIPTION

[0018] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0019] As attached Figure 1~2 As shown, a miniaturized quad-band active navigation antenna with high phase center stability is composed of a structural mounting platform 1, a feed network layer 7, a low noise amplifier circuit layer 8, and a passive antenna 9; As attached Figure 3As shown, the passive antenna 9, the structural installation platform 1, the feed network layer 7, and the low noise amplifier circuit layer 8 are arranged sequentially from top to bottom, the passive antenna 9, the feed network layer 7, and the low noise amplifier circuit layer 8 are fixed by conductive glue, the countersunk screws 2 sequentially pass through the four symmetrical positions of the passive antenna 9, the structural installation platform 1, the feed network layer 7, and the low noise amplifier circuit layer 8 and are fixed with nuts 4, and the pan head screws 3 sequentially pass through the passive antenna 9, the structural installation platform 1, the feed network layer 7, and the low noise amplifier circuit layer 8 and are fixed with nuts 4, and the upper and lower stacked combinations are connected. The composite fixing method saves space to a great extent. While ensuring the antenna radiation performance, it also has the characteristics of simple installation and high integration. The shape of the structural mounting platform 1 can also be circular or other shapes. As long as it is a metal reflective ground used as an antenna, the passive antenna 9 is on the top, and the feeding network layer 7 and the low-noise amplifier circuit layer 8 are on the bottom. The connection method through the intermediate metal vias is also regarded as the same connection method. If the horizontal occupied space is sufficient, the feeding network layer 7 and the low-noise amplifier circuit layer 8 can also be placed in one layer and the same connection method can be used.

[0020] The passive antenna 9 is composed of four layers of the same dielectric substrate stacked together to reduce the cost of substrate materials. The cross-sectional area of ​​the dielectric substrate of the upper layer is smaller than the cross-sectional area of ​​the dielectric substrate of the lower layer. A radiation patch is attached to the upper side of the dielectric substrate, and copper foil is covered on the lower side of the dielectric substrate. Symmetrical debugging branches are arranged around the radiation patch. The two feeding pads of the radiation patch are located as feeding points, and the feeding points are in a dual feeding form, thereby providing good phase center stability for each working frequency band; four pairs of feeding points are placed in four directions with a rotation of 90°, which is convenient for lower layer wiring and improves isolation between frequency bands; The structural installation platform 1 is circular or square in shape; The center of the quad-band active navigation antenna is hollowed out to provide a threaded via, and metal vias are provided at the four corners of the structural mounting platform 1, the feed network layer 7, and the low-noise amplifier circuit layer 8. The core screws improve the radiation performance of the antenna, while also taking into account the anti-burning and short-circuit design of the navigation antenna. The conductive glue and the four-corner screws further fix the antenna structure, making it more stable and reliable.

[0021] The metal vias are located at the four corners of the structural installation platform 1, the feed network layer 7, and the low noise amplifier circuit layer 8; The feed network layer 7 includes an orthogonal hybrid network circuit 70 and a combined output feed pad; The orthogonal hybrid network circuit 70 combines and outputs satellite signals, and the combined signals are output to the low noise amplifier circuit layer 8 through the metal probe; The low noise amplifier circuit 8 includes four frequency bands of anti-burning active low noise amplifier filter circuit; The anti-burning active low-noise amplification and filtering circuit comprises a pre-selection filter, a limiter, a low-noise amplifier, a band-pass filter, and a power supply circuit; The pre-selection filter filters the combined signal; The limiter limits the high-power signal in-band or out-of-band; The low noise amplifier performs low noise amplification on the satellite signal; The bandpass filter suppresses near-end interference signals; The power supply circuit outputs satellite signals and inputs external direct current power.

[0022] Furthermore, a miniaturized quad-band active navigation antenna with high phase center stability is provided, wherein the dielectric substrate comprises a first dielectric substrate 103, a second dielectric substrate 203, a third dielectric substrate 303, and a fourth dielectric substrate 403; The dielectric substrates are chamfered on all sides, and the first dielectric substrate 103, the second dielectric substrate 203, the third dielectric substrate 303, and the fourth dielectric substrate 403 are aligned along the geometric center points of the dielectric substrates and stacked from top to bottom to ensure the non-circularity of the directional diagrams of each frequency band; The radiation patches include a frequency band S radiation patch 102, a frequency band GPS / B1 radiation patch 202, a frequency band B3 radiation patch 302, and a frequency band B2b radiation patch 402; The radiation patch of the next layer serves as the metal ground of the radiation patch of the previous layer, generating resonance of the working frequency band of the radiation patch, thereby realizing the quad-band working performance of the antenna; The middle part of the radiation patch is a square, and one corner of an isosceles right triangle is cut off from the four corners of the radiation patch. The corner cutting changes the current phase of the radiation patch in the direction of two feeding points, thereby optimizing the axial ratio radiation pattern performance of this frequency band.

[0023] Furthermore, a miniaturized quad-band active navigation antenna with high phase center stability is provided, wherein the feeding points include four pairs of feeding points, which are placed in four directions at 90° rotation intervals to facilitate lower layer wiring and improve isolation between frequency bands, and are respectively a first feeding point 21, a second feeding point 22, a third feeding point 23, and a fourth feeding point 24; The first feeding point 21 is the two feeding pad positions of the frequency band S radiation patch 102, the second feeding point 22 is the two feeding pad positions of the frequency band GPS / B1 radiation patch 202, the third feeding point 23 is the two feeding pad positions of the frequency band B3 radiation patch 302, and the fourth feeding point 24 is the two feeding pad positions of the frequency band B2b radiation patch 402; The feeding point 21, the second feeding point 22, the third feeding point 23, and the fourth feeding point 24 are placed through different metal probes, and the tops of the different metal probes are respectively connected to the welding pads of the feeding point 21, the second feeding point 22, the third feeding point 23, and the fourth feeding point 24. The bottom of the metal probe passes through the structural mounting platform 1 and is welded to the feeding network layer 7. The metal probe realizes 0° and 90° dual feed phase differences through the feeding network layer 7, thereby realizing right-hand circular polarization performance. The distance from the center is about one-third of the patch size. By adjusting the distance from the center, the impedance matching performance of the antenna can be adjusted, thereby improving the antenna gain.

[0024] Furthermore, a miniaturized quad-band active navigation antenna with high phase center stability, wherein the debugging branches include a first square debugging branch 101, a second square debugging branch 401, a first T-shaped debugging branch 201, and a second T-shaped debugging branch 301; The frequency band S radiation patch 102 is provided with a first square debugging branch 101 symmetrically arranged on all sides, and the frequency band B2b radiation patch 402 is provided with a second square debugging branch 401 symmetrically arranged on all sides; The resonance point movement of the frequency band S radiation patch 102 and the frequency band B2b radiation patch 402 is controlled by the length of the square debugging branches, which on the one hand realizes the miniaturization of the antenna units of the B2b band and the S band, and on the other hand plays a role in debugging the antenna after processing. Affected by the actual processing accuracy error, the narrowband antenna will have a certain frequency offset.

[0025] The frequency band GPS / B1 radiation patch 202 is provided with a first T-shaped debugging branch 201 symmetrically arranged on all sides, and the frequency band B3 radiation patch 302 is provided with a second T-shaped debugging branch 301 symmetrically arranged on all sides; The resonance point movement of the frequency band GPS / B1 radiation patch 202 and the frequency band B3 radiation patch 302 is adjusted by adjusting the length of the T-shaped debugging branch. Since the working frequency bands of the frequency bands B3, GPS / B1 and the underlying patch are relatively close, and the T-shaped branch can achieve a better degree of miniaturization than the long branch under the same space limitation, the T-shaped debugging branch is adopted. On the one hand, the miniaturization of the antenna unit of the B3 and GPS / B1 frequency bands can be achieved to a better degree, and at the same time, the length of the T-shaped branch can be controlled to facilitate post-processing debugging. The debugging branch can also be set to a stepped shape, which can also play a similar role.

[0026] Further, in a miniaturized quad-band active navigation antenna with high phase center stability, the band B3 radiation patch 302 further includes but is not limited to an SRR slot structure 304; The SRR gap structure 304 is composed of two C-shaped rings that are open and nested with each other; The SRR slot structure 304 also includes but is not limited to increasing the equivalent current path of the antenna, the equivalent current path suppresses the high-order modes of the antenna, improves the impedance matching of the antenna, and better realizes the miniaturization of the B3 antenna unit; the ring can also be a complementary nested ring of a square or other shape, which can play a similar role.

[0027] As attached Figure 4 As shown, a miniaturized quad-band active navigation antenna with high phase center stability, wherein there are four orthogonal hybrid network circuits 70, each of which is rotated 90° and placed in four directions to combine and output four pairs of 0° and 90° satellite signals from four frequency bands respectively; The combined output feed pads include an S-band combined output feed pad 71 , a GPS / B1-band combined output feed pad 72 , a B3-band combined output feed pad 73 , and a B2b-band combined output feed pad 74 .

[0028] Furthermore, a miniaturized quad-band active navigation antenna with high phase center stability is provided, wherein the material of the dielectric substrate includes ceramic and polyphenylene ether resin, the dielectric constant of the dielectric substrate is 10.2, and the thickness of the dielectric substrate is 4 mm; The structural installation platform 1 is made of aluminum; As attached Figures 1 to 5 As shown, the feed network layer 7 and the low noise amplifier circuit layer 8 are copper-clad double-layer boards, and the dielectric substrate is a microwave composite dielectric copper-clad substrate TP-2, including a flame-retardant copper-clad epoxy glass fiber cloth laminate and a bonding sheet; The thickness of the dielectric substrate is 1.5 mm, and the dielectric constant of the dielectric substrate is 4.2; The size of the first dielectric substrate 103 is 25 mm*25 mm, the size of the second dielectric substrate 203 is 31 mm*31 mm, the size of the third dielectric substrate 303 is 39 mm*39 mm, and the size of the fourth dielectric substrate 403 is 50 mm*50 mm; The side length of the middle part of the band S radiation patch 102 is 18.5 mm, the side length of the middle part of the band GPS / B1 radiation patch 202 is 28.5 mm, the side length of the middle part of the band B3 radiation patch 302 is 35.5 mm, and the side length of the middle part of the band B2b radiation patch 402 is 43 mm; The radius of the feeding point is 1 mm; The diameters of the S-band combined output feed pad 71, the GPS / B1-band combined output feed pad 72, the B3-band combined output feed pad 73, and the B2b-band combined output feed pad 74 are 1 mm, and the diameter of the through hole of the pad is 0.4 mm; The metal via radii are 1 mm and 0.4 mm; The threaded through hole has a diameter of 2.3 mm.

[0029] As attached Figure 5 As shown, a miniaturized quad-band active navigation antenna with high phase center stability, the working principle of the anti-burning active low-noise amplification and filtering circuit is: The combined input signal of the feed network layer 7 is filtered by the pre-selection filter to suppress the far-end interference signal; The filter outputs the filtered combined signal to the limiter, and the limiter limits the existing in-band or out-of-band high-power signal; The limiter outputs the limited signal to the low noise amplifier for low noise amplification to reduce the link noise figure; The low noise amplifier outputs the noise-amplified satellite signal to the bandpass filter to suppress the near-end interference signal; The bandpass filter outputs the satellite signal that has been limited, amplified and filtered to the power supply circuit, and the power supply circuit outputs the satellite signal; The power supply circuit is an output / input path for satellite signals and external DC power supply.

[0030] As attached Figure 6 As shown, a miniaturized four-band active navigation antenna with high phase center stability also includes an information receiving and transmission system for the active navigation antenna. The information receiving and transmission system for the active navigation antenna saves placement area by overlapping the modules and making the feed network layer 7 independent. The four-band passive antenna passes through the structural mounting platform 1 and is welded to the feed network layer 7. The signals of each working frequency band form complete circular polarization signals through the feed network layer 7 and are transmitted to the low noise amplifier circuit layer 8. After the signal processing such as limiting, filtering, and amplification of the low noise amplifier circuit layer 8, the signals are output to the connector.

[0031] As attached Figure 7 As shown, the antenna achieves quad-frequency operation under the premise of low cost, miniaturization, high integration and high phase center stability.

[0032] As attached Figure 8 As shown, (a) is the S-band antenna gain pattern, (b) is the GPS / B1-band antenna gain pattern, (c) is the B3-band antenna gain pattern, and (d) is the B2b-band antenna gain pattern. The antenna has good gain performance in each operating frequency band.

[0033] A miniaturized quad-band active navigation antenna with high phase center stability, the working principle is: A miniaturized quad-band active navigation antenna with high phase center stability, including its performance design, installation method and information receiving and transmission system; it has the functions of receiving, filtering and amplifying GPS / Beidou B1, Beidou B3, short message B2b and S-band satellite navigation signals.

[0034] A stacked design is adopted, which includes, from top to bottom, a 4-frequency passive antenna 9, a structural mounting platform 1, a feed network layer 7 and a low-noise amplifier circuit layer 8. The antenna feed pin passes through the structural mounting platform 1 and is welded to the feed network layer 7. After the signals of each working frequency band are synthesized at 0° and 90° phases of the four orthogonal hybrid network circuits of the feed combiner network board, a complete circular polarization signal is formed and transmitted to the low-noise amplifier circuit board, and then output to the connector after being limited, filtered and amplified by the low-noise amplifier circuit.

[0035] In order to achieve quad-band working performance, resonance is generated by stacking multiple radiation patches, and the radiation patch of the lower layer is used as the metal ground of the upper layer, thereby achieving the goal of multi-band operation; in order to ensure the phase center stability performance of multi-bands, each layer of the radiation patch of the antenna contains an independent dual feeding point, which can be used for the system to achieve multi-frequency high-precision positioning performance; each layer of the substrate is made of the same material, and is loaded with square debugging branches, T-shaped debugging branches and SRR gap structure 304, so as to achieve antenna miniaturization at low cost; the passive antenna 9, the feed network layer 7, and the low-noise amplifier circuit layer 8 are glued and fixed with conductive glue, and at the same time, three pairs of pan head screws are used to penetrate and reinforce the four types of stacks at the geometric center of the antenna, and the four screws on the edge further reinforce the whole. This composite installation method of conductive glue and screws can not only simplify the stable structure, but also the center screw can be used as a short-circuit probe to achieve the anti-burning characteristics of the navigation antenna and optimize and improve the miniaturization performance of the antenna. While not affecting the electrical performance of the antenna, it ensures the integration of the multi-layer antenna and the complexity of fixing.

[0036] The passive antenna part includes 4 layers of metal radiation patches, which are responsible for the radiation performance of 4 working frequency bands respectively; each unit adopts dual feeding mode to achieve the performance improvement of circular polarization phase center stability; when one layer of patches is working in resonance, its adjacent lower radiation patch is used as the metal ground of the resonant patch, which requires the size of the lower patch to be larger than the size of the upper radiation patch. Therefore, from top to bottom, they are the resonant radiation patches of Beidou S band, GPS / Beidou B1 band, Beidou B3 band and Beidou short message B2b band; the substrates of the 4 layers of radiation patches are all made of the same composite ceramic material TP-2 to save processing costs; in order to achieve miniaturization and increase the processing adjustability of the antenna, four-sided symmetrical debugging branches are added; among them, since the working frequency bands of B3 and GPS / B1 are extremely close, the resonant patches will be similar in size, which is not conducive to the radiation performance of the antenna. Therefore, T-type debugging branches are used in the B3 and GPS / B1 layers, and SRR gap structure is further added to the B3 layer to achieve miniaturization performance.

[0037] The structural mounting platform 1 includes structural mounting parts and mounting screws, which are combined with conductive adhesive to complete the installation and fixation of the active antenna.

[0038] The feed network layer 7 includes four frequency band orthogonal hybrid network circuits, eight feed pin holes from antenna array elements, and four feed pin holes output to the low noise amplifier board. Each orthogonal hybrid network circuit combines the 0° and 90° satellite signals from the antenna array elements into one path and outputs it to the corresponding feed pin hole.

[0039] The low noise amplifier circuit layer 8 includes limiting filter amplifier circuits for four frequency bands. The circuit composition of each frequency band is consistent, including five parts: pre-selection filter, limiter, low noise amplifier, bandpass filter and feeding network. The first-stage pre-selection filter selects different models according to different frequency bands to suppress interference signals far away from the working frequency band; the limiter is used as the satellite signal input to the second stage to limit the high-power signal in or out of the band to protect the subsequent active circuit; the third stage is a low noise amplifier to perform low-noise amplification on weak satellite signals; the fourth stage is a bandpass filter, different models are selected for different frequency bands, the passband is narrower, and the interference signals near the working frequency band are suppressed; the fifth stage is a feeding network, which separates the externally provided DC feed and RF output signal, and extracts DC power to power the low noise amplifier circuit.

[0040] This solution uses a miniaturized four-frequency active navigation antenna with high phase center stability to ensure high phase center stability under the premise of four-frequency operation; the higher the stability of the antenna phase center, the higher the positioning accuracy; each working frequency band adopts dual feed to achieve circular polarization, which solves the problem of low phase center stability caused by the multi-frequency design of the antenna and realizes multi-frequency high-precision positioning; the dielectric material responsible for each working frequency band is selected from the same material to save cost; miniaturization processing is adopted, and the SRR structure and T-shaped branches are used to realize the miniaturization of the B3 frequency band; an information receiving and transmission system for an active navigation antenna is provided, which realizes a stacked composite fixing method with high integration and no impact on radiation performance.

[0041] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A miniaturized quad-band active navigation antenna with high phase center stability, characterized in that: It is composed of a structural installation platform (1), a feed network layer (7), a low noise amplifier circuit layer (8), and a passive antenna (9); The passive antenna (9), the structural installation platform (1), the feed network layer (7), and the low noise amplifier circuit layer (8) are arranged in sequence from top to bottom; the passive antenna (9), the feed network layer (7), and the low noise amplifier circuit layer (8) are fixed between the layers by conductive glue; the countersunk screws (2) are passed through the four symmetrical positions of the passive antenna (9), the structural installation platform (1), the feed network layer (7), and the low noise amplifier circuit layer (8) in sequence and are fixed with the nuts (4); and the pan head screws (3) are passed through the passive antenna (9), the structural installation platform (1), the feed network layer (7), and the low noise amplifier circuit layer (8) in sequence and are fixed with the nuts (4); The passive antenna (9) is composed of four layers of stacked identical dielectric substrates, the cross-sectional area of ​​the dielectric substrate of the upper layer is smaller than the cross-sectional area of ​​the dielectric substrate of the lower layer, a radiation patch is attached to the upper side of the dielectric substrate, a copper foil is covered on the lower side of the dielectric substrate, and symmetrical debugging branches are arranged around the radiation patch; The two feeding pads of the radiation patch are located as feeding points, and the feeding points are in a dual feeding form; The structural mounting platform (1) is circular or square in shape; A threaded via is provided at the center of the quad-band active navigation antenna, and metal vias are provided at the four corners of the passive antenna (9), the structural mounting platform (1), the feed network layer (7), and the low noise amplifier circuit layer (8); The metal vias are located at the four corners of the structural mounting platform (1), the feed network layer (7), and the low noise amplifier circuit layer (8); The feed network layer (7) comprises an orthogonal hybrid network circuit (70) and a combined output feed pad; The orthogonal hybrid network circuit (70) combines and outputs satellite signals, and the combined signals are output to the low noise amplifier circuit layer (8) through a metal probe; The low noise amplifier circuit (8) comprises four frequency bands of burn-out resistant active low noise amplifier filter circuits; The anti-burning active low-noise amplification and filtering circuit comprises a pre-selection filter, a limiter, a low-noise amplifier, a band-pass filter, and a power supply circuit; The pre-selection filter filters the combined signal; The limiter limits the high-power signal in-band or out-of-band; The low noise amplifier performs low noise amplification on the satellite signal; The bandpass filter suppresses near-end interference signals; The power supply circuit outputs satellite signals and inputs external direct current power.

2. The miniaturized quad-band active navigation antenna with high phase center stability according to claim 1, characterized in that: The dielectric substrate comprises a first dielectric substrate (103), a second dielectric substrate (203), a third dielectric substrate (303), and a fourth dielectric substrate (403); The dielectric substrates are chamfered on all sides, and the first dielectric substrate (103), the second dielectric substrate (203), the third dielectric substrate (303), and the fourth dielectric substrate (403) are aligned along the geometric center points of the dielectric substrates and stacked from top to bottom; The radiation patches include a frequency band S radiation patch (102), a frequency band GPS / B1 radiation patch (202), a frequency band B3 radiation patch (302), and a frequency band B2b radiation patch (402); The radiation patch of the next layer serves as the metal ground of the radiation patch of the previous layer, generating resonance in the working frequency band of the radiation patch; The middle part of the radiation patch is a square, and one corner of an isosceles right triangle is cut off from the four corners of the radiation patch. The cut corner changes the current phase of the radiation patch in the direction of two feeding points.

3. The miniaturized quad-band active navigation antenna with high phase center stability according to claim 2, characterized in that: The feeding points include four pairs of feeding points, which are arranged along four directions at 90° rotation intervals, and are respectively a first feeding point (21), a second feeding point (22), a third feeding point (23), and a fourth feeding point (24); The first feeding point (21) is the position of two feeding pads of the frequency band S radiation patch (102), and the second feeding point (22) is The third feeding point (23) is the two feeding pad positions of the frequency band GPS / B1 radiation patch (202), the third feeding point (23) is the two feeding pad positions of the frequency band B3 radiation patch (302), and the fourth feeding point (24) is the two feeding pad positions of the frequency band B2b radiation patch (402); The feed point (21), the second feed point (22), the third feed point (23), and the fourth feed point (24) are placed via different metal probes, the tops of the different metal probes are respectively connected to the welding pads of the feed point (21), the second feed point (22), the third feed point (23), and the fourth feed point (24), the bottoms of the metal probes pass through the structural mounting platform (1) and are welded to the feed network layer (7), and the metal probes achieve 0° and 90° dual feed phase differences via the feed network layer (7).

4. The miniaturized quad-band active navigation antenna with high phase center stability according to claim 2, characterized in that: The debugging branches include a first square debugging branch (101), a second square debugging branch (401), a first T-shaped debugging branch (201), and a second T-shaped debugging branch (301); The frequency band S radiation patch (102) is provided with a first square debugging branch (101) that is symmetrical on all sides, and the frequency band B2b radiation patch (402) is provided with a second square debugging branch (401) that is symmetrical on all sides; The resonance point movement of the frequency band S radiation patch (102) and the frequency band B2b radiation patch (402) is controlled by the length of the square debugging branch; The frequency band GPS / B1 radiation patch (202) is provided with a first T-shaped debugging branch (201) that is symmetrical all around, and the frequency band B3 radiation patch (302) is provided with a second T-shaped debugging branch (301) that is symmetrical all around; The resonance points of the frequency band GPS / B1 radiation patch (202) and the frequency band B3 radiation patch (302) are moved by adjusting the length of the T-shaped adjustment branch.

5. The miniaturized quad-band active navigation antenna with high phase center stability according to claim 2, characterized in that: The frequency band B3 radiation patch (302) further includes but is not limited to an SRR slot structure (304); The SRR gap structure (304) is composed of two C-shaped or square rings that are open and nested with each other; The SRR slot structure (304) further includes but is not limited to increasing an equivalent current path of the antenna, and the equivalent current path suppresses higher-order modes of the antenna.

6. The miniaturized quad-band active navigation antenna with high phase center stability according to claim 2, characterized in that: There are four orthogonal hybrid network circuits (70) in total, each of which is rotated 90 degrees and placed in four directions to combine and output four pairs of 0° and 90° satellite signals from four frequency bands respectively; The combined output feed pads include an S-band combined output feed pad (71), a GPS / B1-band combined output feed pad (72), a B3-band combined output feed pad (73), and a B2b-band combined output feed pad (74).

7. The miniaturized high phase center stability quad-band active navigation antenna according to claim 6, characterized in that: The material of the dielectric substrate includes ceramic and polyphenylene ether resin, the dielectric constant of the dielectric substrate is 10.2, and the thickness of the dielectric substrate is 4 mm; The structural mounting platform (1) is made of aluminum; The feed network layer (7) and the low noise amplifier circuit layer (8) are copper-clad double-layer boards, and the dielectric substrate comprises a flame-retardant copper-clad epoxy glass fiber cloth laminate and an adhesive sheet; The thickness of the dielectric substrate is 1.5 mm, and the dielectric constant of the dielectric substrate is 4.2; The size of the first dielectric substrate (103) is 25 mm*25 mm, the size of the second dielectric substrate (203) is 31 mm*31 mm, the size of the third dielectric substrate (303) is 39 mm*39 mm, and the size of the fourth dielectric substrate (403) is 50 mm*50 mm; The side length of the middle part of the frequency band S radiation patch (102) is 18.5 mm, the side length of the middle part of the frequency band GPS / B1 radiation patch (202) is 28.5 mm, the side length of the middle part of the frequency band B3 radiation patch (302) is 35.5 mm, and the side length of the middle part of the frequency band B2b radiation patch (402) is 43 mm; The radius of the feeding point is 1 mm; The diameters of the S-band combined output feed pad (71), the GPS / B1-band combined output feed pad (72), the B3-band combined output feed pad (73), and the B2b-band combined output feed pad (74) are 1 mm, and the diameter of the through holes of the pads is 0.4 mm; The metal via radii are 1 mm and 0.4 mm; The threaded through hole has a diameter of 2.3 mm.

8. The miniaturized quad-band active navigation antenna with high phase center stability according to claim 1, characterized in that: The working principle of the anti-burning active low-noise amplification and filtering circuit is: The combined input signal of the feed network layer (7) is filtered by a pre-selection filter to suppress the far-end interference signal; The filter outputs the filtered combined signal to the limiter, and the limiter limits the existing in-band or out-of-band high-power signal; The limiter outputs the limited signal to the low noise amplifier for low noise amplification to reduce the link noise figure; The low noise amplifier outputs the noise-amplified satellite signal to the bandpass filter to suppress the near-end interference signal; The bandpass filter outputs the satellite signal that has been limited, amplified and filtered to the power supply circuit, and the power supply circuit outputs the satellite signal; The power supply circuit serves as an output / input path for satellite signals and external DC power supply.

9. The miniaturized quad-band active navigation antenna with high phase center stability according to claim 1, characterized in that: Also included is an information receiving and transmitting system for an active navigation antenna. The information receiving and transmitting system for an active navigation antenna saves placement area by overlapping the modules and making the feed network layer (7) independent. The four-band passive antenna passes through the structural installation platform (1) and is welded to the feed network layer (7). The signals of each working frequency band are transmitted to the low-noise amplifier circuit layer (8) through the feed network layer (7) to form a complete circular polarization signal. The low-noise amplifier circuit layer (8) processes the signal through limiting, filtering, and amplification and outputs it to the connector.

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