Ultra-low sidelobe dual-polarization active row feed array with variable unit number and unequal power division

Abstract

According to the ultra-low sidelobe dual-polarized active row feed array with variable unit number and unequal power division, a plurality of dual-polarized antenna units are respectively connected to power dividers according to feed polarization, a plurality of power dividers are connected to multifunctional chips, and a plurality of multifunctional chips are connected to a total power division network; the dual-polarized antenna units, the power dividers and the multifunctional chips form an active subarray, the power dividers form a weighted power division network through a series-feed / parallel-feed network, the weighted power division network is divided into a vertical polarization power division network and a horizontal polarization power division network, and a plurality of dual-polarized antenna units connected to the same power divider form a unit array; the first microwave plate, the second microwave plate, the third microwave plate and the mother board are sequentially arranged from top to bottom, the dual-polarized antenna unit and the horizontal polarization power division network are located on the front face of the first microwave plate, the vertical polarization power division network is located on the back face of the second microwave plate, the total power division network is located on the back face of the third microwave plate, and the multifunctional chip is located on the back face of the mother board.

Description

Technical Field

[0001] This invention belongs to the field of microwave antenna technology, specifically relating to an ultra-low sidelobe array technology. Background Technology

[0002] Weather radar is an effective monitoring device for severe weather. Traditional weather radar has gone through three stages: analog, digital, and Doppler. The new generation of weather radar is developing towards dual polarization and phased array systems.

[0003] Sidelobe level is a crucial performance indicator for weather radar array subsystems. Employing ultra-low sidelobe technology can significantly improve the overall performance of weather radar. Maintaining high performance while effectively reducing costs is a key objective for practical engineering applications.

[0004] To save costs, phased array radars consisting of row-feed arrays with phased elevation and mechanical azimuth scanning are a common type of weather radar. In the azimuth direction, ultra-low sidelobes are achieved through fixed amplitude weighting. In the elevation direction, cell-level digitization and high-precision digital amplitude modulation are used to achieve ultra-low sidelobes.

[0005] The main engineering types of ultra-low sidelobe row feed arrays include traveling wave waveguide arrays and passive row feeds with unequal power distribution. Traveling wave waveguide arrays achieve low sidelobe amplitude weighting by creating slots of different angles, eccentricities, widths, and depths along the narrow side of the waveguide. A matched load is connected at the termination, enabling good matching over a wide frequency band. Passive row feeds with unequal power distribution use a power-dividing network composed of unequal power dividers to weightedly distribute power across the entire row of antenna elements, achieving a low azimuth sidelobe design.

[0006] The aforementioned arrays, each with its own advantages, are used in weather radars for different purposes, but they also have certain drawbacks. Traveling wave waveguide arrays, due to their azimuth frequency sweep angle, have a zenith scanning blind zone; the larger the frequency offset angle, the larger the scanning dome blind zone. Furthermore, the azimuth beam is fixed, preventing the formation of multi-beam arrays. While passive traveling waveguide arrays with unequal power distribution feeds have beams pointing in the normal direction, they suffer from significant losses. Summary of the Invention

[0007] To address the technical challenges of large scanning blind zones and high losses, a variable element number and unequal power distribution scheme was adopted. Each element array has a unequal number of elements but equal input power, resulting in different energy distributions among the antenna elements in arrays with varying element numbers, forming a first-level amplitude weighting. Element arrays with a large number of elements employ unequal power dividers to further refine the power allocation between elements, forming a second-level amplitude weighting. The transmit / receive link amplifies or attenuates the overall amplitude of each element array by different magnitudes, forming a third-level amplitude weighting. The feed amplitude ratio of the row feed array elements tends towards a Taylor weighted distribution or other low sidelobe weighted distributions, achieving ultra-low sidelobe weighting for both transmit and receive. Element arrays with a small number of elements use equal power dividers to reduce design costs. This enables simultaneous operation with dual-polarization, achieving a transmit sidelobe of -34.2dB, a receive sidelobe of -39.8dB, and a transmit / receive lobes sum of -73.5dB, improving the radar's anti-jamming and anti-ground clutter capabilities. By using a four-channel multi-functional RF front-end chip, active link costs are reduced, while the feed link length is significantly shortened, feed line loss is effectively reduced, and phased array aperture efficiency is improved. To address the requirements for row feed cell size and weighting depth, an optimization algorithm-based design iteration is implemented to achieve the low sidelobe requirements of row feed arrays of corresponding sizes.

[0008] The row feed array includes dual-polarized antenna elements, power dividers, multi-function chips, and a total power divider network. Multiple dual-polarized antenna elements are connected to the power dividers, multiple power dividers are connected to the multi-function chips, and multiple multi-function chips are connected to the total power divider network.

[0009] Dual-polarized antenna elements, power dividers, and multi-functional chips constitute an active subarray. The power divider forms a weighted power dividing network through a series-feed / parallel-feed network, which is divided into a vertical polarization power dividing network and a horizontal polarization power dividing network. Multiple dual-polarized antenna elements connected to the same power divider constitute a unit array.

[0010] The row feed array consists of microwave board 1, microwave board 2, microwave board 3, and mother board from top to bottom. The dual-polarized antenna element and the horizontal polarization power divider network are located on the front of microwave board 1, the vertical polarization power divider network is located on the back of microwave board 2, the total power divider network is located on the back of microwave board 3, and the multi-functional chip is located on the back of the mother board.

[0011] The number of dual-polarized antenna elements contained in each unit array is different. The number of dual-polarized antenna elements, power dividers, and multi-functional chips contained in each active subarray is also different. Power dividers are divided into equal power and unequal power types.

[0012] The row feed array contains multiple active subarrays, each active subarray contains multiple rows of cell arrays, each row of cell arrays corresponds to one channel of a multi-functional chip, each multi-functional chip has multiple channels, and each channel corresponds to one cell array.

[0013] The total power divider network is divided into two equal-power dividers, one vertical and one horizontal, corresponding to the vertical polarization power divider network and the other horizontal polarization power divider network, respectively. The amplitude weighting ratio of the two is the same for the dual-polarization antenna elements. Each row of multi-functional chips corresponds to one port of the equal-power divider network, realizing the average distribution or synthesis of signal power among multiple multi-functional chips.

[0014] The multi-functional chip includes a transceiver switch, a high-power amplifier, a low-noise amplifier, an attenuator, and a phase shifter. The two transceiver switches are divided into two paths: a transmit link consisting of a high-power amplifier and a receive link consisting of a low-noise amplifier and an attenuator.

[0015] Each channel corresponds to a set of transceiver switches, high-power amplifiers, low-noise amplifiers, attenuators, and phase shifters. One end is connected to a power divider, and the other end is connected to the main power divider network through the phase shifter, forming a complete transceiver link to realize signal amplification, attenuation, and phase shifting.

[0016] Each multi-functional chip has one port connected to a power divider port, and each power divider port is connected to all horizontal or vertical polarization feed ports in a unit array, enabling the signal power among multiple dual-polarization antenna units to be distributed or combined in different proportions.

[0017] There is a metal floor with a gap between microwave board one and microwave board two, and there is an air cavity between microwave board two and microwave board three.

[0018] The horizontally polarized power divider network uses microstrip lines to feed the dual-polarized antenna elements horizontally, while the vertically polarized power divider network uses slot coupling to feed the dual-polarized antenna elements vertically.

[0019] The multi-functional chips for horizontal polarization and the multi-functional chips for vertical polarization are independent of each other and arranged in two parallel rows.

[0020] The signal is transmitted from the three-layer microwave board through the interlayer metal wires to the multi-functional chip on the back of the motherboard for distribution or synthesis, and then back to the total power distribution network for interconnection with other ports.

[0021] By setting the number of dual-polarized antenna elements in each unit array, the power distribution or combining ratio between dual-polarized antenna elements in the same unit array, the amplification value of the high-power amplifier, and the attenuation value of the attenuator, ultra-low sidelobes can be achieved.

[0022] Assuming the number of active subarrays is N, the number of antenna elements per row is Nx, the number of channels per multi-functional chip is Nc, and the number of elements per row array is Ns, then Ns = N·Nc. By using an exhaustive search method or a genetic algorithm, the number of dual-polarized antenna elements in each array can be optimized to minimize the sidelobe level.

[0023] Based on the array size and network layout, the preset number of unit arrays is Ne. If the number of a certain unit array is less than or equal to Ne, its amplitude weighting has a small effect on improving the sidelobe, so an equal power divider is used. If the number of a certain unit array is greater than Ne, an unequal power divider is used to make the power distribution between units exhibit a certain curvature, close to the Taylor weighting trend of the target sidelobe level, and reduce the additional sidelobe rise caused by continuous step amplitude. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a row feed array.

[0025] Figure 2 This is a schematic diagram of a cell array.

[0026] Figure 3 This is a schematic diagram of the array link.

[0027] Figure 4 This is a schematic diagram of a multi-functional chip.

[0028] Figure 5 This is a diagram of a row feed array structure.

[0029] Figure 6 This is a side view of a row feed array.

[0030] Figure 7 This is a top view of a row feed array.

[0031] Figure 8 This is a bottom view of a row feed array.

[0032] Figure 9 This is a diagram showing the distribution of the number of array cells.

[0033] Figure 10 This is a transmission link amplitude distribution diagram.

[0034] Figure 11 This is a diagram showing the amplitude distribution of the receiving link.

[0035] Figure 12 It is a transmission lobe diagram.

[0036] Figure 13 It is the received lobe diagram. Detailed Implementation

[0037] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0038] The row feed array includes dual-polarized antenna elements 1, power dividers, multi-function chips 3, and a total power divider network 4. Multiple dual-polarized antenna elements 1 are connected to the power dividers according to their feed polarization. Multiple power dividers are connected to the multi-function chips 3, and multiple multi-function chips 3 are connected to the total power divider network. Figure 1 As shown.

[0039] A dual-polarized antenna element 1, a power divider, and a multi-functional chip 3 constitute an active subarray 5. The power divider forms a weighted power dividing network 2 through a series-feed / parallel-feed network, which is divided into a vertically polarized power dividing network 21 and a horizontally polarized power dividing network 22. Multiple dual-polarized antenna elements 1 connected to the same power divider constitute a unit array 11, such as... Figure 2 As shown.

[0040] The number of dual-polarized antenna elements 1 contained in each unit array 11 is different. The number of dual-polarized antenna elements 1, power dividers, and multi-functional chips 3 contained in each active subarray 5 is also different. The power dividers are divided into equal power and unequal power types.

[0041] The row feed array comprises multiple active subarrays 5, each active subarray 5 contains multiple row cell arrays 11, each row cell array 11 corresponds to one channel of a multi-function chip 3, and each multi-function chip 3 has multiple channels, each channel corresponding to one cell array 11, such as... Figure 3 As shown.

[0042] The total power divider network 4 is divided into two equal power dividers, one vertical and one horizontal, corresponding to the vertical polarization power divider network 21 and the other horizontal polarization power divider network 22, respectively. The amplitude weighting ratio of the two is the same for the dual-polarization antenna element 1. Each row of multi-function chips 3 corresponds to one port of the equal power divider, realizing the average distribution or synthesis of signal power among multiple multi-function chips 3.

[0043] The multi-functional chip 3 includes a transceiver switch 31, a high-power amplifier 32, a low-noise amplifier 33, an attenuator 34, and a phase shifter 35. The two transceiver switches 31 are connected to form two paths: a transmit link consisting of the high-power amplifier 32 and a receive link consisting of the low-noise amplifier 33 and the attenuator 34. Figure 4 As shown.

[0044] Each channel corresponds to a set of transceiver switches 31, high-power amplifiers 32, low-noise amplifiers 33, attenuators 34, and phase shifters 35. One end is connected to a power divider, and the other end is connected to the total power divider network 4 through the phase shifter 35, forming a complete transceiver link to realize signal amplification, attenuation, and phase shifting.

[0045] Each multi-function chip 3 has one port connected to the combined port of a power divider, and each power divider's port is connected to all the horizontal or vertical polarization feed ports in a unit array 11, enabling the signal power among multiple dual-polarization antenna units 1 to be distributed or combined in different proportions.

[0046] The row feed array, from top to bottom, consists of microwave board 1, microwave board 2, microwave board 3, and the mother board. The dual-polarized antenna element 1 and the horizontal polarization power divider network 21 are located on the front of microwave board 1, the vertical polarization power divider network 22 is located on the back of microwave board 2, the total power divider network 4 is located on the back of microwave board 3, and the multi-functional chip 3 is located on the back of the mother board. Figure 5 As shown.

[0047] There is a slit metal floor between microwave board one and microwave board two, and an air cavity between microwave board two and microwave board three. Figure 6 As shown.

[0048] The horizontally polarized power divider network 21 uses microstrip lines to feed the dual-polarized antenna elements horizontally, while the vertically polarized power divider network 22 uses slot coupling to feed the dual-polarized antenna elements vertically. Figure 7 As shown.

[0049] The multi-functional chip 3 for horizontal polarization and the multi-functional chip 3 for vertical polarization are independent of each other and arranged in two parallel rows, such as Figure 8 As shown.

[0050] The signal is transmitted from the three-layer microwave board through the interlayer metal wire to the multi-functional chip 3 on the back of the motherboard for distribution or synthesis, and then returns to the total power distribution network 4 to interconnect with other ports.

[0051] The number of dual-polarized antenna elements 11 in each unit array 11, the power distribution or combining ratio between dual-polarized antenna elements in the same unit array 11, the amplification value of the high-power amplifier 32, and the attenuation value of the attenuator 33 can be optimized to achieve ultra-low sidelobes.

[0052] Assuming the number of active subarrays is N, the number of antenna elements per row is Nx, the number of channels per multi-functional chip is Nc, and the number of elements per row array is Ns, then Ns = N·Nc. By using an exhaustive search method or a genetic algorithm, the number of dual-polarized antenna elements in each array can be optimized to minimize the sidelobe level.

[0053] Based on the array size and network layout, the preset number of unit arrays is Ne. If the number of a certain unit array is less than or equal to Ne, its amplitude weighting has a small effect on improving the sidelobe, so an equal power divider is used. If the number of a certain unit array is greater than Ne, an unequal power divider is used to make the amplitude of the edge unit array lower than the Taylor weight of the level of the target sidelobe, thus suppressing the sidelobe rise.

[0054] When Nc=4, the optimal solution obtained by exhaustive optimization is Nx=150, Ns=32, dx=0.5226λ0, where λ0 is the free space wavelength corresponding to the center frequency. The number of elements in each 11-element array is as follows: Figure 9As shown, the amplitude distribution of the transmission link is as follows: Figure 10 As shown, the amplitude distribution of the receiving link is as follows: Figure 11 As shown, the emitted lobes are as follows Figure 12 As shown, the received beam lobe is as follows Figure 13 As shown, its sidelobe level is -34.2dB and its main lobe width is 0.96 degrees.

[0055] The above are embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A dual-polarized active row-feed array with variable unit number and unequal power distribution, characterized in that, include: The system comprises dual-polarized antenna elements, power dividers, multi-function chips, and a total power dividing network. Multiple dual-polarized antenna elements are connected to power dividers according to their feed polarization. Multiple power dividers are connected to multi-function chips, and multiple multi-function chips are connected to the total power dividing network. The dual-polarized antenna elements, power dividers, and multi-function chips constitute an active subarray. The power dividers form a weighted power dividing network through series / parallel feed networks, which is divided into vertical polarization power dividing networks and horizontal polarization power dividing networks. Multiple dual-polarized antenna elements connected to the same power divider constitute a unit array. From top to bottom, the system consists of microwave board 1, microwave board 2, microwave board 3, and a mother board. The dual-polarized antenna elements and the horizontal polarization power dividing network are located on the front of microwave board 1, the vertical polarization power dividing network is located on the back of microwave board 2, the total power dividing network is located on the back of microwave board 3, and the multi-function chips are located on the back of the mother board. Each unit array contains a different number of dual-polarized antenna elements, and each active subarray contains a different number of dual-polarized antenna elements, power dividers, and multi-function chips. The power dividers are divided into equal-power and unequal-power types.

2. The ultra-low sidelobe dual-polarized active row-feed array with variable unit number and unequal power distribution according to claim 1, characterized in that, The row feed array comprises multiple active subarrays, each active subarray comprises multiple row cell arrays, each row cell array corresponds to one channel of a multi-functional chip, each multi-functional chip has multiple channels, and each channel corresponds to one cell array.

3. The ultra-low sidelobe dual-polarized active row-feed array with variable unit number and unequal power distribution according to claim 1, characterized in that, The total power divider network is divided into two equal-power power dividers, one vertical and one horizontal, corresponding to the vertical polarization power divider network and the other horizontal polarization power divider network. The amplitude weighting ratio of the two is the same for the dual-polarization antenna element. The horizontal polarization power divider network feeds the dual-polarization antenna element horizontally using a microstrip line, while the vertical polarization power divider network feeds the dual-polarization antenna element vertically using a slot coupling method. Each row of multi-functional chips corresponds to one port of an equal-power power divider, enabling the average distribution or synthesis of signal power among multiple multi-functional chips; one port of each multi-functional chip is connected to the combined port of a power divider, and the port of each power divider is connected to all horizontal or vertical polarization feed ports in a unit array, enabling the distribution or synthesis of signal power among multiple dual-polarization antenna units in different proportions.

4. The ultra-low sidelobe dual-polarized active row-feed array with variable unit number and unequal power distribution according to claim 1, characterized in that, The multi-functional chip includes: a transceiver switch, a high-power amplifier, a low-noise amplifier, an attenuator, and a phase shifter. The two transceiver switches are divided into two paths: a transmit link composed of a high-power amplifier and a receive link composed of a low-noise amplifier and an attenuator. Each channel corresponds to a set of transceiver switches, a high-power amplifier, a low-noise amplifier, an attenuator, and a phase shifter. One end is connected to a power divider, and the other end is connected to the main power divider network through the phase shifter, forming a complete transceiver link to realize signal amplification, attenuation, and phase shifting.

5. The ultra-low sidelobe dual-polarized active row-feed array with variable unit number and unequal power distribution according to claim 1, characterized in that, There is a metal ground plane with a gap between microwave board one and microwave board two, and an air cavity between microwave board two and microwave board three; the signal is transmitted from the three microwave boards to the multi-functional chip on the back of the motherboard for distribution or synthesis through the interlayer metal wire, and then returns to the total power distribution network and interconnects with other ports; the multi-functional chip for horizontal polarization and the multi-functional chip for vertical polarization are independent of each other and are arranged in two parallel rows.

6. The ultra-low sidelobe dual-polarized active row-feed array with variable unit number and unequal power distribution according to claim 1, characterized in that, Also includes: By setting the number of dual-polarized antenna elements in each unit array, the power distribution or combining ratio between dual-polarized antenna elements in the same unit array, the amplification value of the high-power amplifier, and the attenuation value of the attenuator, ultra-low sidelobes can be achieved.

7. The ultra-low sidelobe dual-polarized active row-feed array with variable unit number and unequal power distribution according to claim 1, characterized in that, Also includes: Assuming the number of active subarrays is N, the number of antenna elements per row is Nx, the number of channels per multi-functional chip is Nc, and the number of elements per row array is Ns, then Ns = N·Nc. By using an exhaustive search method or a genetic algorithm, the number of dual-polarized antenna elements in each array can be optimized to minimize the sidelobe level.

8. The ultra-low sidelobe dual-polarized active row-feed array with variable unit number and unequal power distribution according to claim 1, characterized in that, Also includes: The number of pre-set unit arrays is Ne based on the array size and network layout. If the number of a certain unit array is less than or equal to Ne, its amplitude weighting has a small effect on improving the sidelobe, so an equal power divider is used. If the number of units in a certain array is greater than Ne, an unequal power divider is used to make the power distribution between units exhibit curvature, approaching the Taylor weighted trend of the target sidelobe level, and reducing the additional sidelobe rise caused by continuous step amplitude.

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