Instrument course antenna distribution unit

Abstract

The invention provides an instrument course antenna distribution unit. A CSB power dividing and phase shifting assembly, an SBO power dividing and phase shifting assembly, a 180-degree bridge assembly and a matched load are only arranged in a cabinet; the CSB power dividing and phase shifting assembly divides the channel CSB signal and the clearance CSB signal into n equal power and then inputs the channel CSB signal and the clearance CSB signal into the 180-degree bridge assembly, the SBO power dividing and phase shifting assembly divides the channel SBO signal and the clearance SBO signal into n equal power and then inputs the channel SBO signal and the clearance SBO signal into the 180-degree bridge assembly, and the 180-degree bridge assembly outputs the signals to the antenna. According to the invention, the purposes of size reduction and compact and flexible layout are achieved, and compared with an integrated power divider and bridge assembly, the cost is lower, and the performance is more stable; by adopting a multi-stage one-to-two superposition mode, the isolation among output ports is improved, and the interference among four paths of input signals is reduced; amplitude and phase adjustment can be realized by replacing components of the attenuation module or the phase shift module, the design is flexible, and later debugging and maintenance are facilitated. All the used devices are domestic devices, so that 100% localization of the instrument course antenna distribution unit is realized.

Description

Technical Field

[0001] The present invention relates to the field of antennas, and in particular to an antenna distribution unit. Background Art

[0002] The Instrument Landing System (ILS) is the most commonly used precision approach and landing equipment in civil aviation, and plays a very important role in aircraft safety and flight punctuality. The instrument landing system is divided into two parts: ground and airborne. The ground equipment consists of a localizer, a glide path beacon, and a pointer beacon. The localizer frequency range is 108.1MHz to 119.95MHz, and a dual-frequency system is used. The channel signal (channel CSB, channel SBO) provides coverage within the range of ±10°, and the clearance signal (clearance CSB, clearance SBO) provides coverage within the range of ±10°.

[0003] The coverage is from ±10° to ±35°. The localizer is mainly composed of antenna array, heading distribution unit, heading antenna monitoring synthesis unit and near-field and far-field monitoring antennas. The existing antenna arrays are divided into 14 elements, 16 elements, 20 elements and 24 elements according to the number of elements, among which 20 elements are the most commonly used. Among them, the heading antenna distribution unit is an important component of the localizer. Its function is to feed the four signals of channel CSB, channel SBO, clearance CSB and clearance SBO output by the transmitter to each antenna element of the localizer antenna array according to the predetermined amplitude and phase. After being radiated by the antenna, they are synthesized in space to form the required channel coverage and provide channel line guidance information for aircraft approach and landing.

[0004] In order to realize the function of the heading antenna distribution unit, it is necessary to build a power divider, a 180° bridge, a phase shifter, and an attenuator functional module in the overall circuit, and connect them according to a specific logic to realize the feeding of four-way signals to the antenna array element. At present, there are two main forms of heading antenna distribution units installed in civil airports, both of which are foreign products. One is based on the principle of microstrip lines to realize the functions of power dividers and phase shifters, and the integrated bridge components are used to realize the function of the heading antenna distribution unit. From a structural point of view, the scheme consists of multiple PCB boards stacked and placed in a cabinet, and each PCB board is connected according to a specific logic. The routing on each PCB board is complicated, and there are a large number of windings and microstrip lines with close spacing. The early design and debugging of this scheme and the subsequent maintenance or replacement of parts are extremely troublesome. Another scheme is to use the principle of lumped parameter circuit to build a phase shifter functional module, and use an integrated power divider and 180° bridge functional module to realize the function of the heading antenna distribution unit. From a structural point of view, the scheme consists of 3 PCB boards laid flat in the cabinet, and each PCB is connected with a cable according to a specific logic to realize the function of the heading antenna distribution unit. Due to the use of integrated devices, the routing on the three PCBs is simple, the layout is clear, and later maintenance is convenient, so this solution is more widely used.

[0005] The operating frequency of the instrument course antenna is 108.1 MHz to 119.95 MHz, and the central wavelength is about 2.7 meters. For a microstrip power divider, the length of its branch line cannot be less than one-quarter of the wavelength, otherwise it is difficult to guarantee the indicators; to achieve the phase shift function, it is necessary to change the length of the microstrip line of the phase shift branch. Based on the air medium, for a 1° phase change, a microstrip line length of 7.5 mm is required, and for a 90° phase change, a microstrip line length of 675 mm is required. The above two points make the preliminary design and debugging, as well as the later maintenance or component replacement of the first solution extremely troublesome.

[0006] For another solution that uses the lumped parameter circuit principle to build a phase shifter function module and is paired with an integrated power divider and 180° hybrid function module to achieve the function of the course antenna distribution unit. Although the wiring is simple, the layout is clear, and the later maintenance is convenient. However, through research on domestic integrated device R & D manufacturers, it is found that only a few manufacturers develop integrated power distribution modules and 180° hybrid modules in this frequency band. In terms of electrical performance, the amplitude accuracy, phase accuracy, isolation degree and other indicators of these devices are poor and cannot meet the usage requirements of the instrument course antenna distribution unit; in terms of price, they are relatively expensive compared to inductors, capacitors, and resistors; as the service life increases, the indicators of the course antenna distribution unit in this solution deviate from the original set values, and the user speculates that it is caused by the integrated devices. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the present invention provides an instrument course antenna distribution unit. Combining the advantages and disadvantages of the above two solutions and the domestic situation, the present invention aims to provide a course antenna distribution unit with 100% domestic production, low cost, stable performance, flexible design, compact layout, and convenient later debugging and maintenance.

[0008] The course antenna distribution unit of the present invention uses the lumped circuit principle and uses inductors, capacitors, and resistors to form function modules such as 1-to-2 equal power division, 180° hybrid, phase shifter, and attenuator. On this basis, according to specific amplitude and phase relationships, a course antenna distribution unit is designed. Through the course antenna distribution unit, 4 signals are fed to 20 antenna elements according to specific amplitude and phase relationships, so as to generate the required field pattern for course coverage and provide course line guidance information for aircraft approach and landing. Among them, 1-to-2 equal power division realizes the equal-amplitude and in-phase distribution of signals, and the 180° hybrid can simultaneously realize the equal-amplitude and in-phase output of one signal and the equal-amplitude and anti-phase output of another signal; the phase shifter mainly realizes the phase change function by changing the values of inductors and capacitors; the attenuator realizes different attenuations by changing the resistance value. These function modules have a compact layout, small size, flexible changes, low cost, and stable performance.

[0009] The technical solution adopted by the present invention to solve its technical problems is:

[0010] An instrument course antenna distribution unit includes a cabinet, a CSB power divider phase shifter assembly, an SBO power divider phase shifter assembly, a 180° hybrid assembly, and a matching load. The CSB power divider phase shifter assembly, the SBO power divider phase shifter assembly, the 180° hybrid assembly, and the matching load are only installed in the cabinet. The CSB power divider phase shifter assembly equally divides the channel CSB and clearance CSB signals into n equal parts and inputs them into the 180° hybrid assembly. The SBO power divider phase shifter assembly equally divides the channel SBO and clearance SBO signals into n equal parts and inputs them into the 180° hybrid assembly. The 180° hybrid assembly outputs the signals to the antenna.

[0011] In the CSB power divider phase shifter assembly and the SBO power divider phase shifter assembly, the 1-to-n equal power division is achieved by stacking multiple 1-to-2 Wilkinson power dividers, which improves the isolation between ports. After stacking multiple 1-to-2 Wilkinson power dividers, the total number of power division channels is greater than n, and some of the 1-to-2 power division channels are idle.

[0012] In the 180° hybrid assembly, for the n signals fed by the CSB power divider phase shifter assembly, each signal is equally divided into two signals with equal amplitude and in-phase, and 2n signals are output to complete the feeding of the channel CSB and clearance CSB signals to 2n antenna elements. For the 10 signals fed by the SBO power divider phase shifter assembly, each signal is equally divided into two signals with equal amplitude and in anti-phase, and 2n signals are output to complete the feeding of the channel SBO and clearance SBO signals to 2n antenna elements.

[0013] The cabinet is of a rectangular structure, made of stainless steel, and has the functions of waterproofing and dustproofing. The cabinet is used to fix the CSB power divider phase shifter assembly, the SBO power divider phase shifter assembly, the 180° hybrid assembly, the matching load, and the cable connection devices between modules. And several rows of hydrophobic holes with a pore diameter of 1 mm are opened at the bottom of the cabinet for drainage.

[0014] The phase shifter for route calibration uses a U-shaped dielectric phase shifter to achieve a phase adjustment of not less than ±10°.

[0015] The channel CSB and clearance CSB signals are input from the transmitter into the CSB power splitter and phase shifter module, where amplitude and phase distribution of 1 to 2n is completed. The channel SBO and clearance SBO signals are input from the transmitter into the SBO power splitter and phase shifter module, where amplitude and phase distribution of 1 to 2n is completed for this module. The n signals output from the CSB power splitter and phase shifter module are respectively connected to the n interfaces of the 180° bridge module, with the interfaces corresponding one by one according to the serial numbers. After each of the n signals passes through a 180° bridge, equal-amplitude and in-phase distribution of 1 to 2 is achieved, and 2n signals are output, completing the feeding of the channel CSB and clearance CSB signals to 2n antenna elements. The n signals output from the SBO power splitter and phase shifter module are respectively connected to the interfaces of the 180° bridge module, with the interfaces corresponding one by one according to the serial numbers. After each of the n signals passes through a 180° bridge, equal-amplitude and anti-phase distribution of 1 to 2 is achieved, and 2n signals are output, completing the feeding of the channel SBO and clearance SBO signals to 2n antenna elements.

[0016] 2n + 4 N-type connectors are installed in the bottom layout of the cabinet. The four connectors, namely COU_CSB, CLR_CSB, COU_SBO, and CLR_SBO, are respectively connected to the four signals of the transmitter input for the channel CSB, channel SBO, clearance CSB, and clearance SBO. The remaining 2n connectors are arranged in two rows and are respectively connected one by one to the 2n interfaces of the 180° bridge module. The 2n connectors feed 2n signals with amplitude and phase into each corresponding antenna element.

[0017] The CSB power splitter and phase shifter module is a double-layer PCB board. The two interfaces, J_COU_CSB and J_CLR_CSB, are respectively the feeding ports for the channel CSB and clearance CSB. The channel CSB signal passes through a 1 to n power splitter composed of multiple 1 to 2 superpositions, and the signal is input into n attenuators. The attenuation values of each attenuator are given according to the amplitude relationship. The n signals then respectively pass through 1 phase shifter to achieve phase adjustment, ensuring that the phases of the n signals are equal here. Finally, the output is completed through the bridge. The output ports of the n channel CSB phase shifters are respectively connected one by one to the n bridge interfaces. The clearance CSB signal passes through a 1 to n power splitter composed of multiple 1 to 2 superpositions, and the signal is input into n attenuators. The attenuation values of each attenuator are given according to the amplitude relationship. The n signals then respectively pass through 1 phase shifter, and finally the output is completed through the bridge.

[0018] In the SBO power splitter and phase shifter module, the two interfaces J_COU_SBO and J_CLR_SBO are the feeding ports for the channel SBO and the clearance SBO respectively. The channel SBO signal undergoes a 1-to-n power split composed of multiple levels of 1-to-2 superposition, and the signal is input into n attenuators. The attenuation values of each attenuator are given according to the amplitude relationship. The n signals then each pass through a phase shifter to achieve phase adjustment, ensuring that the n signals have equal phases here. Finally, the output is completed through an n-way bridge; the clearance CSB signal undergoes a 1-to-n power split composed of multiple levels of 1-to-2 superposition, and the signal is input into n attenuators. The attenuation values of each attenuator are given according to the amplitude relationship. The n signals then each pass through a phase shifter to achieve phase adjustment, ensuring that the n signals have equal phases here. Finally, the output is completed through a bridge.

[0019] The 180° bridge module is a double-layer PCB board, composed of n 180° bridges arranged in parallel. There are mounting holes on the PCB board, which cooperate with the mounting posts in the cabinet to play a fixing role. It has 4n SMA connectors, which are connected to the n output ports of the CSB power splitter and phase shifter module in sequence through coaxial cables to achieve equal-amplitude and in-phase output of signals; it is connected to the n output ports of the SBO power splitter and phase shifter module in sequence through coaxial cables to achieve equal-amplitude and anti-phase output of signals; 2n SMA connectors are connected to 2n connectors on the cabinet in sequence through cables, and the 2n connectors are connected to the antenna elements to achieve the feeding of four signals to 2n antenna elements.

[0020] The beneficial effects of the present invention are as follows: Based on the lumped parameter circuit principle, function modules such as 1-to-2 equal power split, 180° bridge, phase shifter, and attenuator are built using inductors, capacitors, and resistors. Using these modules, the functions of the instrument course antenna distribution unit are realized according to the amplitude and phase relationships. The power split and other function modules built using lumped devices play the role of reducing size and having a compact and flexible layout compared to microstrip lines, and have lower costs and more stable performance compared to integrated power split and bridge modules; by adopting the method of multiple levels of 1-to-2 superposition, the isolation degree between output ports is improved, and the interference between four input signals is reduced; the amplitude and phase adjustment can be realized by replacing the components of the attenuation module or the phase shifter module, with flexible design and convenient for later debugging and maintenance; all the devices used are domestic devices, realizing 100% localization of the instrument course antenna distribution unit. Brief Description of the Drawings

[0021] Figure 1 Composition diagram of the course antenna distribution unit

[0022] Figure 2 Principle block diagram of the course antenna distribution unit

[0023] Figure 3 Schematic diagram of the cabinet of the course antenna distribution unit Figure 3 (a) is the schematic diagram of the cabinet of the course antenna distribution unitFigure 3 (b) is a schematic diagram of the cabinet connector.

[0024] Figure 4 Schematic diagram of the CSB power splitter and phase shifter assembly

[0025] Figure 5 Schematic diagram of the SBO power splitter and phase shifter assembly.

[0026] Figure 6 Schematic diagram of the 180° bridge assembly

[0027] Figure 7 Radiation pattern of the four-way signal synthesis of the course antenna.

[0028] Figure 8 Course beacon DDM curve

[0029] Among them, 1 - cabinet, 2 - CSB power splitter and phase shifter assembly, 3 - SBO power splitter and phase shifter assembly, 4 - 180° bridge assembly, 5 - high-power matching load, 6 - phase shifter for route calibration, 61 - mounting hole, 62 - phase shifter output port, 31 - mounting pillar, 32 - hydrophobic hole. Specific implementation mode

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] An instrument course antenna distribution unit includes a cabinet, a CSB power splitter and phase shifter assembly, an SBO power splitter and phase shifter assembly, a 180° bridge assembly, a matching load, and a phase shifter for route calibration.

[0032] The CSB power splitter and phase shifter assembly equally divides the channel CSB and clearance CSB signals into 10 equal parts and inputs them into the 180° bridge assembly. The SBO power splitter and phase shifter assembly equally divides the channel SBO and clearance SBO signals into 10 equal parts and inputs them into the 180° bridge assembly. The 1-to-2 equal power splitting, 180° bridge, phase shifter, and attenuator function modules involved are all built by inductors, capacitors, and resistors, and can be compactly arranged; the power splitting and other modules built by components are more stable in performance and lower in cost compared to integrated devices; in the CSB power splitter and phase shifter assembly and the SBO power splitter and phase shifter assembly, the method of superimposing multiple 1-to-2 Wilkinson power splitters is used to achieve 1-to-10, improving the isolation between ports and reducing the mutual interference between signals; during debugging and later maintenance, changing the resistance value of the attenuator can achieve the transformation of the amplitude of each signal to the antenna element, and changing the inductance and capacitance values of the phase shifter can achieve the phase change of each signal to the antenna element, with flexible design, achieving the purpose of convenient later debugging and maintenance.

[0033] The 180° bridge component equally divides and in-phase distributes the 10 signals fed by the CSB power splitter and phase shifter component, with each path achieving a 1-to-2 equal-amplitude and in-phase distribution, outputting 20 signals to complete the feeding of the channel CSB and clearance CSB signals to 20 antenna elements. It equally divides and anti-phase distributes the 10 signals fed by the SBO power splitter and phase shifter component, with each path achieving a 1-to-2 equal-amplitude and anti-phase distribution, outputting 20 signals to complete the feeding of the channel SBO and clearance SBO signals to 20 antenna elements. The amplitude accuracy of the bridge built with inductors and capacitors is within 0.1 dB, and the phase accuracy is within 3 degrees, far higher than the existing integrated bridge components in this frequency band in China, and the overall cost has decreased significantly.

[0034] The cabinet is of rectangular structure, made of stainless steel, with waterproof and dustproof functions. The cabinet is used for fixing the CSB power splitter and phase shifter component, SBO power splitter and phase shifter component, 180° bridge component, high-power matching load, and cable connection devices between modules. And several rows of hydrophobic holes with a pore diameter of 1 mm are opened at the bottom of the cabinet for drainage.

[0035] The phase shifter for route calibration uses a U-shaped dielectric phase shifter to achieve a phase adjustment of not less than ±10°.

[0036] As Figure 1 shown, the course antenna distribution unit includes a cabinet 1, a CSB power splitter and phase shifter component 2, an SBO power splitter and phase shifter component 3, a 180° bridge component 4, a high-power matching load 5, and a phase shifter 6 for route calibration. Each component is connected by a cable. To achieve the function of amplitude and phase distribution of four signals as shown in Table 1, the connection between each component needs to be carried out according to Figure 2 the principle block diagram.

[0037] Table 1 Amplitude and Phase Table of Course Antenna Distribution Unit Figure 2It is the principle block diagram of the course antenna distribution unit. Combining with the distribution relationship in Table 1, it can be seen that the course CSB and clearance CSB signals are input from the transmitter to the CSB power splitter and phase shifter module. The CSB power splitter and phase shifter module completes the amplitude and phase distribution of 1 to 10. Among them, ports 1 and 2 of the clearance are unloaded. The course SBO and clearance SBO signals are input from the transmitter to the SBO power splitter and phase shifter module. This module completes the amplitude and phase distribution of 1 to 10. Among them, ports 1 and 4 of the clearance SBO signal are unloaded. The 10 signals C_J1 to C_J10 output by the CSB power splitter and phase shifter module are respectively connected to the interfaces J_CSB_1 to J_CSB_10 of the 180° bridge module. The interfaces correspond one by one according to the serial numbers. After each of the 10 signals passes through a 180° bridge, it realizes the equal-amplitude and in-phase distribution of 1 to 2, and outputs 20 signals, completing the feeding of the course CSB and clearance CSB signals to 20 antenna elements. The 10 signals S_J1 to S_J10 output by the SBO power splitter and phase shifter module are respectively connected to the interfaces J_SBO_1 to J_SBO_10 of the 180° bridge module. The interfaces correspond one by one according to the serial numbers. After each of the 10 signals passes through a 180° bridge, it realizes the equal-amplitude and anti-phase distribution of 1 to 2, and outputs 20 signals, completing the feeding of the course SBO and clearance SBO signals to 20 antenna elements.

[0038] As Figure 3 (a) shows, the cabinet of the course antenna distribution unit is a rectangular structure, processed from stainless steel material, with waterproof and dustproof functions. There are installation supports 31 inside the cabinet. The installation supports 31 are used for the fixation of the CSB power splitter and phase shifter module 2, the SBO power splitter and phase shifter module 3, the 180° bridge module 4, the matching load 5, the phase shifter 6 for course calibration and the cable connection devices between components. 24 N-type connectors are arranged and installed at the bottom of the cabinet. The connector numbers are as Figure 3 (b) shows. The four connectors COU_CSB, CLR_CSB, COU_SBO and CLR_SBO are respectively connected to the four signals of the transmitter input course CSB, course SBO, clearance CSB and clearance SBO. P_1 to P_20 are arranged in two rows and are respectively connected to J1 to J20 of the 180° bridge module one by one. The 20 connectors of P_1 - P_20 realize the feeding of 20 signals with amplitude and phase to each corresponding antenna element. Among them, a phase shifter 6 for adjusting the course line is connected in series between J5 and P_5. The input port 61 of the phase shifter 6 for adjusting the course line is connected to J5, and the output port 62 of the phase shifter is connected to P_5. By using this phase shifter to adjust the phase of port P_5, the calibration of the course line can be realized. The connections between all interfaces are realized through cables. Several rows of hydrophobic holes 32 with a pore diameter of 1 mm are opened at the bottom of the cabinet for drainage.

[0039] The implementation principle of the CSB power splitter and phase shifter module is as Figure 4As shown, the CSB power splitter and phase shifter component is a double - layer PCB board. According to the Figure 4 logical relationship in it, the power splitting, phase shifting, attenuation and 180° bridge function modules built by inductors, capacitors and resistors are laid out on the board. There are mounting holes around the double - layer PCB board, which cooperate with the mounting posts 31 in the cabinet to play a fixing role. Among them, the two interfaces J_COU_CSB and J_CLR_CSB are the channel CSB power feed port and the clearance CSB power feed port respectively. C_J1 to C_J10 are 10 power splitting and phase shifting output ports, and are subsequently connected one - to - one with Figure 6 J_CSB_1 to J_CSB_10 in it. As can be seen from Figure 4 , the channel CSB signal passes through a 1 - to - 10 power splitting composed of multiple 1 - to - 2 superpositions, and the signal is input into 10 attenuators. The attenuation values of each attenuator are given by the amplitude relationship in Table 1. The 10 - path signals then each pass through a 1 - path phase shifter to realize the phase adjustment, ensuring that the 10 - path signals have equal phases here. Finally, the signals pass through the bridge and are output from the C_J1 to C_J10 ports. As can be seen from Table 1, P_3, P_18, P_4, P_17, P_5, P_16, P_6, P_15, P_7, P_14, P_8, P_13 bear more energy. To avoid burning the patch loads on bridges 1 to 10 due to excessive power, the loads at the C_J3 - C_J8 input ports, which bear more energy, are led out with Ld_3 - Ld_8 connectors for connecting Figure 1 the 6 high - power loads 5 in it. As can be seen from Table 1, the clearance CSB signal has no energy fed into ports P1 and P_2 and is in an unloaded state. Therefore, the clearance CSB signal passes through a 1 - to - 8 power splitting composed of multiple 1 - to - 2 superpositions, and the signal is input into 8 attenuators. The attenuation values of each attenuator are given by the amplitude relationship in Table 1. The 8 - path signals then each pass through a 1 - path phase shifter to realize the phase adjustment, ensuring that the 8 - path signals have equal phases here. Finally, the signals pass through the bridge and are output from the C_J3 to C_J10 ports.

[0040] The SBO power splitter and phase shifter component is as shown in Figure 5 . Its layout and function are similar to those of the CSB power splitter and phase shifter component. Among them, the two interfaces J_COU_SBO and J_CLR_SBO are the channel SBO power feed port and the clearance SBO power feed port respectively. S_J1 - S_J10 are 10 power splitting and phase shifting output ports, and are connected one - to - one with Figure 6 J_SBO_1 to J_SBO_10 in it. As can be seen from Figure 5It can be seen that the channel SBO signal is divided into 10 signals through a 1-to-10 power divider composed of multiple levels of 1-to-2 stacking. The signal is input into 10 attenuators, and the attenuation values of each attenuator are given according to the amplitude relationship in Table 1. Then, the 10 signals respectively pass through 1 phase shifter to adjust the phase, ensuring that the phases of the 10 signals are equal here. Finally, the signals are output through a 10-way bridge from ports S_J1 to S_J10. As can be seen from Table 1, there is no energy feeding into ports P_1 and P_4 for the clearance SBO signal, which is in an open-circuit state. Therefore, the clearance CSB signal is divided into 8 signals through a 1-to-8 power divider composed of multiple levels of 1-to-2 stacking. The signal is input into 8 attenuators, and the attenuation values of each attenuator are given according to the amplitude relationship in Table 1. Then, the 8 signals respectively pass through 1 phase shifter to adjust the phase, ensuring that the phases of the 8 signals are equal here. Finally, the signals are output through a bridge from ports S_J2, S_J3, and C_J5 to C_J10.

[0041] Further, as Figure 6 shown, the 180° bridge component is a double-layer PCB board, which consists of 10 parallel 180° bridges. The 180° bridge is built by inductors and capacitors. There are mounting holes 61 on the PCB board, which cooperate with the mounting posts 31 in the cabinet to play a fixing role. There are 40 SMA connectors, and the connector numbers are as Figure 6 shown. Among them, J_CSB_1 - J_CSB_10 are connected to the 10 output ports C_J1 - C_J10 of the CSB power dividing and phase shifting component through coaxial cables in sequence, realizing the equal-amplitude and in-phase output of the signal at port J_CSB_1 at ports J1 and J20, the equal-amplitude and in-phase output of the signal at port J_CSB_2 at ports J2 and J19, and so on; J_SBO_1 - J_SBO_10 are connected to the 10 output ports S_J01 - S_J10 of the SBO power dividing and phase shifting component through coaxial cables in sequence, realizing the equal-amplitude and anti-phase output of the signal at port J_SBO_1 at ports J1 and J20, the equal-amplitude and anti-phase output of the signal at port J_SBO_2 at ports J2 and J19, and so on. Further, connectors J01 - J20 are connected to P_1 - P_20 on the cabinet through cables in sequence, and P_1 - P_20 are subsequently connected to the antenna elements to realize the feeding of four signals to 20 antenna elements.

[0042] So far, the amplitude and phase distribution in Table 1 are achieved for the four signals of channel CSB, channel SBO, clearance CSB, and clearance SBO. Through experimental verification, the amplitude accuracy of this course antenna distribution unit is within ±1 dB, and the phase accuracy is within ±3°. It has relatively high accuracy indicators. The synthetic antenna radiation pattern generated based on this course antenna distribution unit is as Figure 7 shown, and the generated DDM curve is as Figure 8 shown, both of which meet the index requirements of the instrument landing ground equipment, thus determining the feasibility of this scheme.

[0043] Compared with the two foreign instrument course antenna distribution units currently in use, the course antenna distribution unit of the present invention has the following advantages:

[0044] 1. Compared with the solution of building a power divider and a phase shifter using microstrip lines, it has a smaller size, flexible layout, and convenient maintenance.

[0045] The operating frequency of the instrument course antenna is 108.1 MHz to 119.95 MHz, and the center wavelength is about 2.7 meters. For a microstrip power divider, the length of its branch line cannot be less than one-quarter of the wavelength, that is, a microstrip line length of 675 mm, otherwise the indicators are difficult to guarantee; to achieve the phase shift function, it is necessary to change the length of the microstrip line in the phase shift branch. Based on air medium, for a 1° phase change, a microstrip line length of 7.5 mm is required, and the greater the phase change, the longer the line length. For a 1-to-2 power divider or a phase shifter built with inductors, capacitors and other components to achieve the same function, it only occupies a space of no more than about 40 mm × 10 mm, and amplitude distribution and phase adjustment are achieved in a fixed space.

[0046] 2. Compared with the solution of using integrated power dividers, phase shifters and bridge components, it has stable performance and lower cost.

[0047] The stability of inductors, capacitors and resistors is higher than that of integrated devices, and the cost of components such as power division and phase shift built by these components is also lower than that of integrated devices. In addition, the indicators of existing domestic integrated devices in this frequency band are poor and cannot meet the use requirements, while using these devices for building makes the design more flexible and the actual indicator accuracy is higher.

[0048] 3. Compared with the two foreign solutions, the interference between signals is smaller.

[0049] In the solution using microstrip lines, due to a large number of wire windings, there will be coupling between lines, which will cause interference between signals; the solution using integrated devices does not adopt a multi-stage superposition method. In particular, the theoretical isolation degree of the built power divider will be lower than that of the 1-to-2 multi-stage superposition method. For each additional stage of superposition, the isolation degree will be improved, and the improvement of the isolation degree is beneficial to reducing the interference between the four-way signals.

[0050] 4. Compared with the two foreign solutions, debugging and later maintenance are more convenient.

[0051] If the amplitude of a certain output signal deviates, after determining the deviation value, the amplitude can be adjusted by replacing the resistor of the attenuation module; if the phase of a certain output signal deviates, the phase can be adjusted by replacing the inductors and capacitors of the phase shift module. The purpose of convenient debugging and later maintenance is achieved.

[0052] 5. Compared with the two domestic solutions, 100% localization of the instrument course antenna distribution unit is achieved.

Claims

1. An instrument course antenna distribution unit, comprising a cabinet, a CSB power divider phase shifter component, an SBO power divider phase shifter component, a 180° hybrid component, and a matching load, characterized in that: In the instrument course antenna distribution unit, the CSB power divider phase shifter component, the SBO power divider phase shifter component, the 180° hybrid component, and the matching load are only in the cabinet; The CSB power divider phase shifter component equally divides the channel CSB and clearance CSB signals into n equal parts and inputs them into the 180° hybrid component. The SBO power divider phase shifter component equally divides the channel SBO and clearance SBO signals into n equal parts and inputs them into the 180° hybrid component. The 180° hybrid component outputs the signals to the antenna.

2. The instrument course antenna distribution unit according to claim 1, characterized in that: In the CSB power divider phase shifter component and the SBO power divider phase shifter component, the 1-to-n is realized by superimposing multiple stages of 1-to-2 Wilkinson power dividers to improve the isolation between ports. After superimposing multiple stages of 1-to-2 Wilkinson power dividers, the total number of power division channels is greater than n, and some of the 1-to-2 power division channels are idle.

3. The instrument course antenna distribution unit according to claim 1, characterized in that: In the 180° hybrid component, each of the n signals fed by the CSB power divider phase shifter component realizes an equal-amplitude and in-phase distribution of 1-to-2, and outputs 2n signals to complete the feeding of the channel CSB and clearance CSB signals to 2n antenna elements; Each of the 10 signals fed by the SBO power divider phase shifter component realizes an equal-amplitude and out-of-phase distribution of 1-to-2, and outputs 2n signals to complete the feeding of the channel SBO and clearance SBO signals to 2n antenna elements.

4. The instrument course antenna distribution unit according to claim 1, characterized in that: The cabinet is of a rectangular structure, made of stainless steel, with waterproof and dustproof functions. The cabinet is used for fixing the CSB power divider phase shifter component, the SBO power divider phase shifter component, the 180° hybrid component, the matching load, and the cable connection devices between modules. And several rows of hydrophobic holes with a pore diameter of 1 mm are opened at the bottom of the cabinet for draining water.

5. The instrument course antenna distribution unit according to claim 1, characterized in that: The phase shifter for route calibration adopts a U-shaped dielectric phase shifter to realize a phase adjustment of not less than ±10°.

6. The instrument course antenna distribution unit according to claim 1, characterized in that: The channel CSB and clearance CSB signals are input from the transmitter into the CSB power splitter and phase shifter module, where the amplitude and phase distribution of 1 to 2n is completed. The channel SBO and clearance SBO signals are input from the transmitter into the SBO power splitter and phase shifter module, where the amplitude and phase distribution of 1 to 2n is completed in this module. The n signals output from the CSB power splitter and phase shifter module are respectively connected to the n interfaces of the 180° bridge module, and the interfaces correspond one by one according to the serial numbers. After each of the n signals passes through a 180° bridge, an equal-amplitude and in-phase distribution of 1 to 2 is achieved, and 2n signals are output, completing the feeding of the channel CSB and clearance CSB signals to 2n antenna elements. The n signals output from the SBO power splitter and phase shifter module are respectively connected to the interfaces of the 180° bridge module, and the interfaces correspond one by one according to the serial numbers. After each of the n signals passes through a 180° bridge, an equal-amplitude and anti-phase distribution of 1 to 2 is achieved, and 2n signals are output, completing the feeding of the channel SBO and clearance SBO signals to 2n antenna elements.

7. The instrument course antenna distribution unit according to claim 1, characterized in that: 2n + 4 N-type connectors are installed in the bottom layout of the cabinet. The four connectors of COU_CSB, CLR_CSB, COU_SBO, and CLR_SBO are respectively connected to the four signals of the transmitter input channel CSB, channel SBO, clearance CSB, and clearance SBO. The remaining 2n connectors are arranged in two rows and are respectively connected to the 2n interfaces of the 180° bridge module one by one. The 2n connectors realize the feeding of 2n signals with amplitude and phase to each corresponding antenna element.

8. The instrument course antenna distribution unit according to claim 1, characterized in that: The CSB power splitter and phase shifter module is a double-layer PCB board. The two interfaces of J_COU_CSB and J_CLR_CSB are respectively the feeding ports for the channel CSB and clearance CSB. The channel CSB signal passes through a 1 to n power splitter composed of multiple 1 to 2 superpositions, and the signal is input into n attenuators. The attenuation values of each attenuator are given according to the amplitude relationship. Each of the n signals then passes through 1 phase shifter to realize the adjustment of the phase, ensuring that the phases of the n signals are equal here. Finally, the output is completed through the bridge. The output ports of the n channel CSB phase shifters are connected to the n bridge interfaces one by one. The clearance CSB signal passes through a 1 to n power splitter composed of multiple 1 to 2 superpositions, and the signal is input into n attenuators. The attenuation values of each attenuator are given according to the amplitude relationship. Each of the n signals then passes through 1 phase shifter to realize the adjustment of the phase, and finally the output is completed through the bridge.

9. The instrument course antenna distribution unit according to claim 1, characterized in that: In the SBO power splitter and phase shifter module, the two interfaces J_COU_SBO and J_CLR_SBO are the feed ports for the channel SBO and the clearance SBO respectively. The channel SBO signal passes through a 1-to-n power splitter composed of multiple levels of 1-to-2 stacking, and the signal is input into n attenuators. The attenuation values of each attenuator are given according to the amplitude relationship. The n signals then each pass through a phase shifter to adjust the phase, ensuring that the phases of the n signals are equal at this point. Finally, the output is completed through an n-way bridge. The clearance CSB signal passes through a 1-to-n power splitter composed of multiple levels of 1-to-2 stacking, and the signal is input into n attenuators. The attenuation values of each attenuator are given according to the amplitude relationship. The n signals then each pass through a phase shifter to adjust the phase, ensuring that the phases of the n signals are equal at this point. Finally, the output is completed through a bridge.

10. The instrument course antenna distribution unit according to claim 1, characterized in that: The 180° bridge module is a double-layer PCB board, composed of n 180° bridges arranged in parallel. Mounting holes are provided on the PCB board to cooperate with the mounting posts in the cabinet for fixing. There are 4n SMA connectors, which are connected to the n output ports of the CSB power splitter and phase shifter module in sequence through coaxial cables to achieve equal-amplitude and in-phase output of signals; they are connected to the n output ports of the SBO power splitter and phase shifter module in sequence through coaxial cables to achieve equal-amplitude and anti-phase output of signals; 2n SMA connectors are connected to 2n connectors on the cabinet in sequence through cables, and the 2n connectors are connected to the antenna elements to achieve the feeding of four signals to 2n antenna elements.

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