A phased array radio frequency front end
By segmenting the array antenna and RF link, and combining the switching modes of the control module, frequency and aperture reuse of the RF channel was achieved, solving the problem of increasing the number of RF channels in broadband arrays, reducing costs and improving efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA SHIPBUILDING IND CORP NO 723 RESEARCH INSTITUTE
- Filing Date
- 2023-09-01
- Publication Date
- 2026-05-12
AI Technical Summary
In phased array antennas, with the development of broadband, the number of radio frequency channels increases, leading to higher costs, insufficient resource integration, limited system multi-task concurrency and multi-functional resource reuse rate. Existing technologies are unable to effectively reduce the number of radio frequency channels and affect antenna performance.
The design employs a segmented approach for array antennas and RF links, including a combination of antenna elements and subarrays. By switching different operating modes through a control module, frequency and aperture reuse of RF channels is achieved, reducing the number of RF channels. High-efficiency T/R components are used to segment and achieve broadband operation.
While achieving broadband operation, the use of RF front-end aperture was optimized, reducing costs, improving the efficiency of T/R components, avoiding resource waste, and meeting high and low frequency gain requirements.
Smart Images
Figure CN117220707B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of phased array technology, and in particular to a phased array radio frequency front end. Background Technology
[0002] As phased arrays evolve towards broadband, the spacing between antenna elements decreases, leading to a dramatic increase in the number of radio frequency (RF) channels and consequently, higher costs. Furthermore, the sheer number of RF channels results in insufficient resource efficiency, limited system multitasking concurrency and multi-functional resource reuse, and poor economic performance. Therefore, reducing the number of RF channels is the most direct way to lower the cost of the RF front-end.
[0003] Currently, the most common methods for reducing the number of RF channels are sparse arrays and subarray-level phased arrays. Sparse arrays have been widely researched and applied in narrowband array antennas, but have not yet been used in broadband array antennas. The reason for the limitation of this technology is that, unlike narrowband arrays which require decoupling, broadband arrays need to utilize the coupling between elements to achieve broadband operation. Using a sparse approach can easily lead to performance degradation of the antenna. Moreover, after sparsening, the distribution of the sparsed antenna elements is irregular, making it difficult to divide the array aperture for use. Subarray-level phased arrays are only suitable for small-angle scanning; as the scanning angle increases, grating lobes are easily formed, thus resulting in their limited application at present. Summary of the Invention
[0004] This application provides a phased array radio frequency front end, which can be used to solve the technical problem of difficulty in reducing the number of radio frequency channels in ultra-wideband arrays.
[0005] A low-cost phased array radio frequency front-end, the radio frequency front-end includes: an array antenna, radio frequency link 1, radio frequency link 2, a feed network, a frequency conversion module, and a control module;
[0006] The array antenna includes m antenna elements A and n antenna subarrays B; each antenna subarray B contains L antenna elements A; the array antenna has a total of m+n*L antenna elements; wherein, the aperture size of the antenna formed by the m antenna elements A is SA, and the aperture size formed by the n antenna subarrays B is SB; the operating bandwidth of the array antenna is f1-f2.
[0007] Antenna subarray B is connected to RF link 1, and antenna element A is connected to RF link 2; the entire RF front end has n RF links 1 and m RF links 2; RF links 1 and RF links 2 are connected to the feed network; the feed network is connected to the frequency conversion module; the control module controls the RF switches in RF links 1 and RF links 2.
[0008] The radio frequency link 1 includes a 1-to-L power divider, a T / R component 1, a filter 1, and a single-pole single-throw radio frequency switch; the 1-to-L power divider is connected to the T / R component 1, the T / R component 1 is connected to the filter 1, and the filter 1 is connected to the single-pole single-throw radio frequency switch; the operating bandwidth of the T / R component 1 is f1-f3, where f3 < f2.
[0009] The RF link 2 includes a single-pole double-throw (SPD) RF switch, a T / R component 2, a T / R component 3, a filter 1, a filter 2, two SPD RF switches, and a 1-to-2 power divider. The SPD RF switch is connected to T / R component 2 and T / R component 3. T / R component 2 is connected to filter 1. Filter 1 is connected to one SPD RF switch. T / R component 3 is connected to filter 2. Filter 2 is connected to the other SPD RF switch. Both SPD RF switches are connected to the 1-to-2 power divider. The operating bandwidth of T / R component 2 is f1-f3, and the operating bandwidth of T / R component 3 is f3-f2.
[0010] Each T / R component includes a transmit / receive switching switch, a power amplifier, an attenuator, a phase shifter, and a low-noise amplifier, used to realize power amplification and amplitude / phase adjustment functions in transmit / receive modes;
[0011] The aforementioned feed network is used for equal amplitude and equal phase distribution of radio frequency signals;
[0012] The frequency conversion module includes up-conversion and down-conversion; when the radio frequency front-end transmits, the excitation signal is up-converted and transmitted to the feed network, distributed by the feed network and then transmitted to the radio frequency link and antenna, radiating into free space; when the radio frequency front-end receives, the signal received from the antenna is transmitted to the feed network through the radio frequency link and then down-converted to output an intermediate frequency signal.
[0013] Optionally, the number of antenna elements in antenna subarray B is L = (f2 / f3)^2; f2 / f3 is an integer.
[0014] Optionally, when the RF front-end operates in f1-f3, the following operating modes are available:
[0015] RF Link 1 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw RF switch to be turned on, and all RF switches of RF Link 2 are turned off. At this time, the aperture of the working RF front-end antenna is SB, and the number of RF channels is n.
[0016] RF Link 2 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw switch to be disconnected, the RF Link 2 single-pole double-throw RF switch to be connected, T / R component 2, and all single-pole single-throw RF switches to be connected. At this time, the working RF front-end antenna aperture is SA and the number of RF channels is m.
[0017] Simultaneous operation mode of RF link 1 and RF link 2: The control module controls the RF link 1 to turn on the single-pole single-throw RF switch, and the RF link 2 to turn on the single-pole double-throw RF switch. T / R component 2 and all single-pole single-throw RF switches are turned on. At this time, the working RF front-end aperture is SA+SB, realizing aperture multiplexing and RF link frequency multiplexing, with the number of RF channels being m+n.
[0018] When the RF front-end is operating in f3-f2, there is only one operating mode:
[0019] RF Link 2 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw switch to be disconnected, the RF Link 2 single-pole double-throw RF switch to be connected, and the T / R component 3 and all single-pole single-throw RF switches to be connected. At this time, the working RF front-end antenna aperture is SA and the number of RF channels is m.
[0020] Optionally, when the RF front end is operating in f1-f3 mode and RF link 1 and RF link 2 are operating simultaneously, the phase of the RF signal after passing through RF link 1 is equal to the phase of the RF signal after passing through RF link 2.
[0021] Optionally, when the RF front end is operating in f1-f3 mode and RF link 1 and RF link 2 are operating simultaneously, the output power of the RF signal after passing through RF link 1 is equal to the output power of the RF signal after passing through RF link 2.
[0022] Optionally, the bandwidth of the 1-to-L power divider is f1-f3, the passband of the filter 1 is f1-f3, the passband of the filter 2 is f3-f2, and the bandwidth of the 1-to-2 power divider is f1-f2.
[0023] Compared with the prior art, the significant advantages of this application are: this application is simple and easy to implement, and can optimize the use of the RF front-end aperture while achieving broadband operation, taking into account the performance of the RF front-end at both high and low frequencies; compared with the traditional broadband phased array architecture, this application has fewer RF channels and lower cost; this application implements the ultra-wideband T / R component in segments, which is more efficient. Attached Figure Description
[0024] Figure 1 A schematic diagram of a low-cost phased array radio frequency front-end provided for embodiments of this application;
[0025] Figure 2 A schematic diagram of the aperture of a low-cost phased array radio frequency front-end array antenna provided for embodiments of this application;
[0026] Figure 3 A low-cost phased array radio frequency front-end radio frequency link 1 is provided for embodiments of this application;
[0027] Figure 4This application provides a low-cost phased array radio frequency front-end radio frequency link 2. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0029] This application provides a low-cost phased array frequency front-end, which includes: an array antenna, a frequency link 1, a frequency link 2, a feed network, a frequency conversion module, and a control module;
[0030] The array antenna consists of m antenna elements A and n antenna subarrays B; each antenna subarray B contains L antenna elements A; the array antenna has a total of m+n*L antenna elements; the aperture size of the antenna formed by the m antenna elements A is SA, and the aperture size formed by the n antenna subarrays B is SB; the operating bandwidth of the array antenna is f1-f2.
[0031] Antenna subarray B is connected to RF link 1, and antenna element A is connected to RF link 2; the entire RF front end has n RF links 1 and m RF links 2; RF links 1 and RF links 2 are connected to the feed network; the feed network is connected to the frequency conversion module; the control module controls the RF switches in RF links 1 and RF links 2 to realize the reuse of RF front end frequency and aperture, reduce RF channels, and reduce costs.
[0032] RF link 1 includes a 1-to-L power divider, a T / R component 1, a filter 1, and a single-pole single-throw RF switch; the 1-to-L power divider is connected to the T / R component 1, the T / R component 1 is connected to the filter 1, and the filter 1 is connected to the single-pole single-throw RF switch; the operating bandwidth of the T / R component 1 is f1-f3, where f3 < f2.
[0033] RF link 2 includes a single-pole double-throw (SPD) RF switch, T / R component 2, T / R component 3, filter 1, filter 2, two SPD RF switches, and a 1-to-2 power divider. The SPD RF switch is connected to T / R component 2 and T / R component 3. T / R component 2 is connected to filter 1. Filter 1 is connected to one SPD RF switch. T / R component 3 is connected to filter 2. Filter 2 is connected to another SPD RF switch. Both SPD RF switches are connected to the 1-to-2 power divider. The operating bandwidth of T / R component 2 is f1-f3, and the operating bandwidth of T / R component 3 is f3-f2.
[0034] The T / R components all include a transmit / receive switch, a power amplifier, an attenuator, a phase shifter, and a low-noise amplifier, which are used to realize power amplification and amplitude and phase adjustment functions in transmit and receive modes;
[0035] The feed network is used for equal amplitude and equal phase distribution of radio frequency signals;
[0036] The frequency conversion module includes up-conversion and down-conversion; when the RF front-end transmits, the excitation signal is up-converted and transmitted to the feed network, distributed by the feed network and then transmitted to the RF link and antenna, radiating into free space; when the RF front-end receives, the signal received from the antenna is transmitted to the feed network through the RF link and then down-converted to output the intermediate frequency signal.
[0037] The number of antenna elements in antenna subarray B is L = (f2 / f3)^2; considering practical applications, f2 / f3 is an integer.
[0038] When the RF front-end operates in f1-f3, it has the following operating modes:
[0039] RF Link 1 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw RF switch to be turned on, and all RF switches of RF Link 2 are turned off. At this time, the aperture of the working RF front-end antenna is SB, and the number of RF channels is n.
[0040] RF Link 2 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw switch to be disconnected, the RF Link 2 single-pole double-throw RF switch to be connected, T / R component 2, and all single-pole single-throw RF switches to be connected. At this time, the working RF front-end antenna aperture is SA and the number of RF channels is m.
[0041] Simultaneous operation mode of RF link 1 and RF link 2: The control module controls the RF link 1 to turn on the single-pole single-throw RF switch, and the RF link 2 to turn on the single-pole double-throw RF switch. T / R component 2 and all single-pole single-throw RF switches are turned on. At this time, the RF front-end aperture is SA+SB, realizing aperture multiplexing and frequency multiplexing of RF links, with the number of RF channels being m+n. Traditional phased array RF front-ends require m+n*L RF channels to achieve the same f1-f3 gain performance. Compared with traditional phased array RF front-ends, the number of RF channels in this invention is reduced by n*(L-1).
[0042] When the RF front-end is operating in f3-f2, there is only one operating mode:
[0043] RF Link 2 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw switch to be disconnected, the RF Link 2 single-pole double-throw RF switch to be connected, and the T / R component 3 and all single-pole single-throw RF switches to be connected. At this time, the working RF front-end antenna aperture is SA and the number of RF channels is m.
[0044] When the RF front end is operating in f1-f3 mode and RF link 1 and RF link 2 are operating simultaneously, the phase of the RF signal after passing through RF link 1 is equal to the phase of the RF signal after passing through RF link 2.
[0045] When the RF front-end operates in f1-f3 mode and RF link 1 and RF link 2 operate simultaneously, the output power of the RF signal after passing through RF link 1 is equal to the output power of the RF signal after passing through RF link 2.
[0046] The bandwidth of a 1-to-L power divider is f1-f3, the passband of filter 1 is f1-f3, the passband of filter 2 is f3-f2, and the bandwidth of a 1-to-2 power divider is f1-f2.
[0047] The present application is further described below with reference to specific embodiments.
[0048] Assume the phased array RF front-end operates between 4.5-18 GHz. The antenna element spacing is 9mm × 9mm. The antenna element gain is -6.4dB at the lower end of the band (4.5 GHz) and 5.5dB at the higher end (18 GHz). The required gain for the RF front-end is 22.5dB at 18 GHz and 17.7dB at 4.5 GHz.
[0049] Based on the above constraints, using a conventional phased array RF front-end architecture, with a grating-lobe-less design at 18GHz as the baseline, only 64 antenna elements are needed to meet the high-frequency 18GHz gain requirement, while 256 antenna elements are needed to meet the low-frequency 4.5GHz gain requirement. Therefore, to balance the high and low frequency gain requirements, the antenna array of a conventional RF front-end is 256 elements, with an aperture size of 207.36 cm². Simultaneously, the RF link connected to the antenna also requires 256 T / R components operating in the 4.5-18GHz range. Currently, the efficiency of T / R components in such a wide frequency band is generally no more than 30%. When this RF front-end operates at high frequencies, aperture resources are severely wasted.
[0050] Using the same antenna elements as described above, this application satisfies the aforementioned constraints as follows: A low-cost phased array radio frequency front-end, such as... Figure 1 As shown, it includes: array antenna, RF link 1, RF link 2, feed network, frequency conversion module, and control module.
[0051] like Figure 2 As shown, the RF front-end array antenna consists of 48 4.5-18 GHz antenna subarrays and 64 4.5-18 GHz antenna elements. Each antenna subarray contains 4 antenna elements. The RF front-end array antenna has a total of 256 antenna elements. The aperture size of the antenna formed by the 64 antenna elements is 51.84 cm², and the aperture size of the antenna formed by the 48 antenna subarrays is 155.52 cm².
[0052] like Figure 3As shown, RF link 1 includes a 1-to-4 Wilkinson power divider for the 4.5-9GHz band, a 4.5-9GHz T / R component 1, a 4.5-9GHz filter 1, and a single-pole single-throw RF switch. T / R component 1 includes a transmit / receive switch, a 4.5-9GHz power amplifier, an attenuator, a phase shifter, and a 4.5-9GHz low-noise amplifier. This component provides power amplification and amplitude / phase adjustment for the 4.5-9GHz signal. Compared to the 4.5-18GHz T / R component, the efficiency of this 4.5-9GHz T / R component 1 is greater than 35%.
[0053] like Figure 4 As shown, RF link 2 includes a single-pole double-throw RF switch, a 4.5-9GHz T / R component 2, a 9-18GHz T / R component 3, a 4.5-9GHz filter 1, a 9-18GHz filter 2, a single-pole single-throw RF switch, and a 1-to-2 Wilkinson power divider for the 4.5-18GHz range. T / R component 2 includes a transmit / receive switch, a 4.5-9GHz power amplifier, an attenuator, a phase shifter, and a 4.5-9GHz low-noise amplifier, providing power amplification and amplitude / phase adjustment functions. T / R component 3 includes a transmit / receive switch, a 9-18GHz power amplifier, an attenuator, a phase shifter, and a 9-18GHz low-noise amplifier, providing power amplification and amplitude / phase adjustment functions. Compared to the 4.5-18GHz T / R component, the efficiency of 4.5-9GHz T / R component 2 and 9-18GHz T / R component 3 is greater than 35%.
[0054] The antenna subarray is connected to the Wilkinson power divider of RF Link 1, which is divided into 4 channels from 4.5 to 9 GHz. The antenna unit is connected to the single-pole double-throw RF switch of RF Link 2. The entire front end has a total of 48 RF Link 1 and 64 RF Link 2.
[0055] RF link 1 and RF link 2 are connected to the power supply network, which can achieve equidistant and in-phase output of 112 RF signals. The power supply network is connected to the frequency converter module.
[0056] The operating modes of the RF front-end are shown in Table 1. The workflow is as follows:
[0057] In transmit mode, the excitation signal is up-converted and transmitted to the feed network. The feed network outputs 112 RF signals, of which 48 are transmitted to RF link 1 and 64 to RF link 2. The control module, based on the operating mode and frequency in Table 1, controls the RF switch states in RF link 1 and RF link 2, selecting the appropriate RF link (see Table 1 for details). The RF signals are then transmitted to the corresponding antennas, achieving frequency and aperture multiplexing. The working antenna aperture area, the number of working antennas, and the number of RF links are shown in Table 1.
[0058]
[0059] In receiving mode, the radio frequency (RF) signal in free space is received by the antenna and transmitted to the RF link. The control module, based on the operating mode and frequency in Table 1, controls the RF switch states in RF link 1 and RF link 2, selecting the appropriate RF link to transmit the received RF signal to the feed network. The feed network then synthesizes the signal and sends it to the down-converter to output the intermediate frequency (IF) signal. The working antenna aperture area, the number of working antennas, and the number of RF links are shown in Table 1.
[0060] As shown in Table 1, when the single-pole single-throw RF switch of RF link 1 is turned on, and the single-pole double-throw RF switch of RF link 2 is turned on, frequency reuse can be achieved in the 4.5-9GHz band, and the apertures of the antenna subarray and antenna elements can be reused. Aperture reuse meets the gain requirements for the low-frequency 4.5GHz band. At this point, the number of RF links is only 112, a 56% reduction compared to the 256 RF links in a traditional phased array RF front-end.
[0061] When the single-pole single-throw switch of RF link 1 is open and the single-pole double-throw RF switch of RF link 2 is closed, and the T / R component 3 and the single-pole single-throw RF switch are closed, the RF front end operates at 9-18GHz, and the antenna unit and RF link 64 participate in the operation. At this time, the antenna aperture meets the gain requirement of high frequency 18GHz.
[0062] In the frequency and aperture multiplexing mode, in order to ensure good radiation pattern synthesis effect, the signals arriving at the feed port of each antenna element must be in phase. In the design, the phase of the RF signal after passing through RF link 1 is equal to the amplitude and phase of the RF signal after passing through RF link 2.
[0063] This invention avoids wasting antenna aperture resources, reduces the number of radio frequency channels, saves costs, improves the efficiency of T / R components, and reduces the pressure of subsequent heat dissipation.
[0064] The embodiment described in this invention is presented merely as a low-cost implementation of a phased array radio frequency front-end, and the description is illustrative rather than limiting. Therefore, those skilled in the art can make other specific implementations based on the design concepts in the appended claims, and various changes in form and detail can be made without departing from the spirit and scope of the invention as defined in the appended claims, without any inventive effort. All of these should be considered within the scope of this invention.
Claims
1. A phased array radio frequency front-end, characterized in that, The radio frequency front end includes: an array antenna, radio frequency link 1, radio frequency link 2, a feed network, a frequency conversion module, and a control module; The array antenna includes m antenna elements A and n antenna subarrays B; each antenna subarray B contains L antenna elements A; the array antenna has a total of m+n*L antenna elements; wherein, the aperture size of the antenna formed by the m antenna elements A is SA, and the aperture size formed by the n antenna subarrays B is SB; the operating bandwidth of the array antenna is f1-f2. Antenna subarray B is connected to RF link 1, and antenna element A is connected to RF link 2; the entire RF front end has n RF links 1 and m RF links 2; RF links 1 and RF links 2 are connected to the feed network; the feed network is connected to the frequency conversion module; the control module controls the RF switches in RF links 1 and RF links 2. The radio frequency link 1 includes a 1-to-L power divider, a T / R component 1, a filter 1, and a single-pole single-throw radio frequency switch; the 1-to-L power divider is connected to the T / R component 1, the T / R component 1 is connected to the filter 1, and the filter 1 is connected to the single-pole single-throw radio frequency switch; the operating bandwidth of the T / R component 1 is f1-f3, where f3 < f2. The RF link 2 includes a single-pole double-throw (SPD) RF switch, a T / R component 2, a T / R component 3, a filter 1, a filter 2, two SPD RF switches, and a 1-to-2 power divider. The SPD RF switch is connected to T / R component 2 and T / R component 3. T / R component 2 is connected to filter 1. Filter 1 is connected to one SPD RF switch. T / R component 3 is connected to filter 2. Filter 2 is connected to the other SPD RF switch. Both SPD RF switches are connected to the 1-to-2 power divider. The operating bandwidth of T / R component 2 is f1-f3, and the operating bandwidth of T / R component 3 is f3-f2. Each T / R component includes a transmit / receive switching switch, a power amplifier, an attenuator, a phase shifter, and a low-noise amplifier, used to realize power amplification and amplitude / phase adjustment functions in transmit / receive modes; The aforementioned feed network is used for equal amplitude and equal phase distribution of radio frequency signals; The frequency conversion module includes up-conversion and down-conversion; when the radio frequency front-end transmits, the excitation signal is up-converted and transmitted to the feed network, then distributed by the feed network and transmitted to the radio frequency link and antenna, radiating into free space; when the radio frequency front-end receives, the signal received from the antenna is transmitted to the feed network through the radio frequency link, and then down-converted to output an intermediate frequency signal.
2. The phased array radio frequency front-end according to claim 1, characterized in that, The number of antenna elements in antenna subarray B is L = (f2 / f3)^2; f2 / f3 is an integer.
3. The phased array radio frequency front-end according to claim 1, characterized in that, When the RF front-end operates in f1-f3, it has the following operating modes: RF Link 1 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw RF switch to be turned on, and all RF switches of RF Link 2 are turned off. At this time, the aperture of the working RF front-end antenna is SB, and the number of RF channels is n. RF Link 2 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw switch to be disconnected, the RF Link 2 single-pole double-throw RF switch to be connected, T / R component 2, and all single-pole single-throw RF switches to be connected. At this time, the working RF front-end antenna aperture is SA and the number of RF channels is m. Simultaneous operation mode of RF link 1 and RF link 2: The control module controls the RF link 1 to turn on the single-pole single-throw RF switch, and the RF link 2 to turn on the single-pole double-throw RF switch. T / R component 2 and all single-pole single-throw RF switches are turned on. At this time, the working RF front-end aperture is SA+SB, realizing aperture multiplexing and RF link frequency multiplexing, with the number of RF channels being m+n. When the RF front-end is operating in f3-f2, there is only one operating mode: RF Link 2 Standalone Working Mode: The control module controls the RF Link 1 single-pole single-throw switch to be disconnected, the RF Link 2 single-pole double-throw RF switch to be connected, and the T / R component 3 and all single-pole single-throw RF switches to be connected. At this time, the working RF front-end antenna aperture is SA and the number of RF channels is m.
4. The phased array radio frequency front-end according to claim 3, characterized in that, When the RF front end is operating in f1-f3 mode and RF link 1 and RF link 2 are operating simultaneously, the phase of the RF signal after passing through RF link 1 is equal to the phase of the RF signal after passing through RF link 2.
5. The phased array radio frequency front-end according to claim 3, characterized in that, When the RF front-end operates in f1-f3 mode and RF link 1 and RF link 2 operate simultaneously, the output power of the RF signal after passing through RF link 1 is equal to the output power of the RF signal after passing through RF link 2.
6. The phased array radio frequency front-end according to claim 1, characterized in that, The bandwidth of the 1-to-L power divider is f1-f3, the passband of filter 1 is f1-f3, the passband of filter 2 is f3-f2, and the bandwidth of the 1-to-2 power divider is f1-f2.