Broadband high-power strip line microwave network circuit

Abstract

The invention belongs to the technical field of microwave antennas, and discloses a broadband high-power strip line microwave network circuit. The Wilkinson single-section power divider is additionally connected with the broadside coupler, the coupling end is connected with the non-isolated power division network, and the tail end of the network is connected with the multiple loads, so that the problem of power resistance of the broadband strip line microwave network is solved; under the condition that the size of a main path is not greatly increased, the working bandwidth of a single-section power divider is improved to octave from 15%, and the average power resistance of a network is increased to dozens of watts.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of microwave antennas, and in particular to a broadband high-power stripline microwave network circuit. Background Art

[0002] As radar antenna operating frequencies continue to rise, research and development of antenna arrays have advanced rapidly. To improve array integration and reduce thickness, active phased array radar arrays often utilize a multilayer board for integrated network design. The RF circuit signals within this integrated network utilize stripline technology, which improves electromagnetic compatibility and reduces transmission losses.

[0003] Stripline RF power splitter networks typically use thin-film resistors as isolation resistors. However, in spaceborne radar arrays, to improve the long-term reliability of the RF network, isolation resistors are typically externally soldered. In this case, the RF network requires connecting the soldered isolation resistors to the surface solder points of the network via vertical transitions. The introduction of these vertical transitions and the lumped parameters of the isolation resistors narrow the RF network's operating bandwidth and degrade electrical performance. Furthermore, this solution is not suitable for frequency bands above 15 GHz.

[0004] Stripline RF power splitter networks with surface-soldered isolation resistors have a higher power handling capacity than those using thin-film resistors. Thin-film resistors typically handle less than 0.25W, while externally soldered resistors can handle around 10W. Due to the introduction of vertical transitions, further improvement in this power handling capacity is difficult.

[0005] To improve the power handling capability of the RF network in the integrated layer of radar arrays on space-borne and airborne platforms, a broadband summator can be used instead of a power splitter. The differential port of the summator serves as an external resistor for isolation. This approach improves power handling, but only increases bandwidth by approximately 40%, and the size is relatively large.

[0006] To improve the power handling capacity of power dividers, existing technologies use air slab lines for the main circuit and microstrip lines for the auxiliary circuit. Existing power dividers can handle kilowatts in the P band, but their large size prevents integration with other circuits. Summary of the Invention

[0007] The present invention aims to provide a broadband, high-power stripline microwave network circuit. This circuit solves the power handling problem of broadband stripline microwave networks by adding a broadside coupler to a conventional single-section Wilkinson power divider, terminating the coupling with a non-isolated power divider network, and connecting multiple loads to the network ends. The circuit also increases the operating bandwidth of the single-section power divider from 15% to an octave without significantly increasing the size of the main circuit, thereby increasing the average power handling capacity of the network to tens of watts.

[0008] The present invention provides a broadband high-power stripline microwave network circuit, comprising a plurality of base units, wherein the base units include a copper clad plate, a prepreg layer, and a metallized hole; The first copper-clad laminate comprises a first dielectric layer, and the upper surface of the first dielectric layer is covered with a first copper foil layer; The second copper clad laminate comprises a second dielectric layer, and the upper surface and the lower surface of the second dielectric layer are covered with a second copper foil layer and a third copper foil layer; The third copper clad laminate comprises a third dielectric layer, and the lower surface of the third dielectric layer is covered with a fourth copper foil layer; The first copper foil layer to the fourth copper foil layer are etched to form a circuit required for the microwave network; According to the lamination order of a first copper clad laminate, a second copper clad laminate, and a third copper clad laminate, the copper clad laminates are hot-pressed into a multi-layer copper clad laminate by placing a first prepreg layer between the first copper clad laminate and the second copper clad laminate, and placing a second prepreg layer between the second copper clad laminate and the third copper clad laminate; Grounding holes are set on the multi-layer copper clad board and metalized to form metalized grounding holes to achieve microwave ground interconnection between the base copper foils.

[0009] Furthermore, the first copper foil layer and the fourth copper foil layer are microwave ground layers, which are shielding grounds for microwave network circuits.

[0010] Furthermore, the second copper foil layer is the main power division network of the microwave network circuit. A transmission line is connected to a Wilkinson power divider. At the intersection of the output ends of the two quarter-wavelength impedance transformation lines of the Wilkinson power divider and the output transmission line, one end of the coupling line of a broadside coupler is connected. The other end of the coupling lines of the two broadside couplers are connected to a circuit with a metallized grounding hole.

[0011] Furthermore, the third copper foil layer includes the other end coupling lines of the two broadside couplers and a rear-end power distribution network. The position of the coupling lines of the third copper foil layer overlaps with the position of the coupling lines of the broadside couplers on the second copper foil layer. The two coupling lines of the third copper foil layer are interconnected at the starting end, and the starting end corresponds to the output end of the two quarter-wavelength impedance transformation lines of the Wilkinson power divider on the second copper foil layer.

[0012] Furthermore, the third copper foil layer is an auxiliary circuit layer, which includes a coupled line circuit and a non-isolated power distribution network. The coupled line circuit is two broadside coupled lines interconnected at one end. The 1-to-2 or 1-to-4 power distribution network has no isolation resistors designed, forming a non-isolated power distribution network. If the output power of the coupled line circuit is less than 1W, the ends of the coupled lines of the two broadside couplers can be directly led to the first copper foil layer or the fourth copper foil layer through a vertical transition, and then soldered with a resistor or connected to the load through a connector; If the output power of the coupled line circuit is greater than 1W, the ends of the coupled lines of the two broadside couplers can be connected to a non-isolated power distribution network. The network branch port leads the signal line to the first copper foil layer or the fourth copper foil layer through a vertical transition and then solders the resistor or connects the load through a connector.

[0013] Furthermore, the thickness of the copper clad laminate is 0.025 mm to 3 mm, the thickness of the prepreg layer is 0.025 mm to 0.2 mm, and the thickness of the copper foil layer is 0.009 mm to 0.036 mm.

[0014] Furthermore, the line width of the coupling line is 0.2 mm to 5 mm, and the length of the coupling line is 0.5 mm to 200 mm.

[0015] The present invention provides a broadband high-power stripline microwave network circuit, which has the following beneficial effects: (1) expanding the working bandwidth of a single-section power divider: by using a method in which the back end of a power divider conversion section with a length of one quarter wavelength is connected to two standard impedance output end lines and two end-to-ground broadside couplers, the working bandwidth of the single-section power divider is increased to an octave; (2) increasing the power handling capacity of the stripline power divider: by using a method in which a broadside coupler is used to replace the isolation resistor of the power divider, the isolation resistor is replaced by an isolation network, and the coupled output power is equally divided by a multi-port load to improve the power handling capacity of the main power divider network; (3) being suitable for Network integration: adopting the stripline structure, the isolation resistor is replaced by a broadband isolation network, and the load end can be externally welded on the surface of the multilayer board or directly connected to the load through a connector, which is suitable for network integration; (4) Improved the electrical performance of the integrated network: the externally welded isolation resistor of the satellite network is replaced by an externally welded load resistor or the load device is directly connected using a connector, eliminating the influence of the vertical transition of the main signal line and the lumped parameters of the isolation resistor on the network performance, and improving the network's performance indicators such as standing wave and isolation; (5) Wide applicable operating frequency range: the operating frequency of this model can be from 10Hz to 40GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram of an application model of a broadband, high-power stripline microwave network circuit according to an embodiment of the present invention; Figure 2 It is a stack-up diagram of a wide-band high-power stripline microwave network circuit application model involved in an embodiment of the present invention; Figure 3 This is a layer 1 circuit diagram of a broadband, high-power stripline microwave network circuit application model according to an embodiment of the present invention; Figure 4 This is a layer 2 circuit diagram of a broadband, high-power stripline microwave network circuit application model according to an embodiment of the present invention; Figure 5This is a circuit diagram of a main power splitter in the second layer circuit diagram of a broadband, high-power stripline microwave network circuit application model according to an embodiment of the present invention; Figure 6 This is a circuit diagram of one of the broadside coupled lines of the coupler connected to the main line impedance transformation location in the second layer circuit diagram of the wideband high-power stripline microwave network circuit application model involved in an embodiment of the present invention and its end grounding circuit diagram; Figure 7 This is a layer 3 circuit diagram of a broadband, high-power stripline microwave network circuit application model according to an embodiment of the present invention; Figure 8 This is a circuit diagram of another broadside coupled line of the coupler in the third layer circuit diagram of the wideband high-power stripline microwave network circuit application model involved in an embodiment of the present invention; Figure 9 It is a power splitter network circuit connected by a coupler in the third layer circuit diagram of the wide-band high-power stripline microwave network circuit application model involved in an embodiment of the present invention; Figure 10 This is a layer 4 circuit diagram of a broadband, high-power stripline microwave network circuit application model according to an embodiment of the present invention; Figure 11 1 is a simulation model diagram of a broadband high-power stripline microwave network circuit according to an embodiment of the present invention; Figure 12 This is a transmission curve from a main port to two split ports of a broadband high-power stripline microwave network circuit power splitter according to an embodiment of the present invention; Description of reference numerals: 21, 22, and 23 are copper clad laminates respectively; 31 and 32 are prepreg layers respectively; 4 is a plurality of metallized holes; 211 is the copper foil layer of the copper clad laminate 21; 212 is the dielectric layer of the copper clad laminate 21; 221 and 223 are the upper and lower copper foil layers of the copper clad laminate 22; 222 is the dielectric layer of the copper clad laminate 22; 231 is the copper foil layer of the copper clad laminate 23; 232 is the dielectric layer of the copper clad laminate 23; 24 is another microwave ground layer made of copper foil. DETAILED DESCRIPTION

[0017] like Figures 1 to 12 As shown, the present invention provides a broadband high-power stripline microwave network circuit. Example 1

[0018] like Figure 1As shown, a broadband high-power stripline microwave network application model 1 is formed by hot pressing three layers of copper clad plates (21, 22, 23) and two layers of semi-cured sheets (31, 32), and interconnection between microwave grounds is achieved through multiple metallized holes (4). The broadband high-power stripline microwave network application model 1 has the characteristic of a wide working frequency band of a single-section power divider. By adding a wide-side coupler to the impedance conversion output ends of the single-section power divider, the working bandwidth of the single-section power divider is increased from 15% to an octave. The broadband high-power stripline microwave network application model 1 has the characteristic of high power resistance. One end of the two broadband couplings is interconnected, and the other end is connected to a non-isolated power division network. The coupled power is not loaded on the end load of the power division network. The more ports the power division network has, the greater the power resistance it can withstand. The broadband high-power stripline microwave network application model 1 has the characteristic of being easy to process. The main two-layer circuits (221, 223) of the microwave network are processed on the upper and lower surfaces of the copper-clad laminate. The alignment accuracy of the coupler wide-side lines distributed on the upper and lower surfaces of the two-layer laminate is easy to ensure. Using a conventional multilayer laminate manufacturing process, lamination can be completed in one step; application model 1 has the characteristic of easy integration. This application model is a laminate that can be applied to microwave multilayer laminates or mixed-pressure multilayer laminates. The dielectric constant and thickness of the copper-clad laminate medium in the model can be adjusted as needed. Application model 1 has the characteristic of improving the electrical performance of the satellite network: this model replaces the externally soldered isolation resistors of the satellite network with externally soldered load resistors or directly uses connectors to connect load devices, eliminating the influence of the vertical transition of the main signal line and the lumped parameters of the isolation resistor on the network performance, and improving the network's performance indicators such as standing wave and isolation.

[0019] like Figure 2 As shown in FIG, the multilayer microwave board stacked structure of the new broadband high-power stripline microwave network application model 1 has a total of 3 layers of microwave dielectric boards, 2 of which are semi-cured and hot-pressed, and then through holes are drilled and metallized.

[0020] A broadband, high-power stripline microwave network circuit comprises copper-clad laminates (21, 22, 23), prepreg layers (31, 32), and a plurality of metallized holes (4). The copper-clad laminate 21 comprises a copper foil layer 211 and a dielectric layer 212; the copper-clad laminate 22 comprises copper foil layers 221 and 223 and a dielectric layer 222; and the copper-clad laminate 23 comprises a copper foil layer 231 and a dielectric layer 232.

[0021] In the early stage, the double-sided copper foil layer (221, 223) is processed on the copper clad plate 22 to obtain the required circuit; the copper foil on one side of the copper clad plates 21, 23 is etched away, leaving the other side of the copper foil, and the single-sided copper foil left on the copper clad plates 21, 23 is processed to obtain the required circuit; according to Figure 2The copper clad laminates 21, 22, and 23 are heat-pressed into a multilayer copper clad laminate through the semi-cured sheet layers 31 and 32; finally, holes are drilled and metallized where grounding is required. The metallized holes (4) connect the upper and lower surfaces (211, 231) of the multilayer laminate and the copper foil on the auxiliary circuit (2212), thereby achieving microwave grounding interconnection between the base copper foils. The thickness of the copper clad laminate is 0.025mm~3mm, the thickness of the semi-cured sheet layer is 0.025mm~0.2mm, and the thickness of the copper foil layer is 0.009mm~0.036mm.

[0022] Copper foil layers 211 and 231 are microwave ground layers, serving as shielding for the stripline network. 24 is another layer of microwave ground made of copper foil. Copper foil layer 221, containing the circuit, is the main power splitter network for the RF network. It uses a conventional Wilkinson power splitter with a standard impedance input. The signal is split into two paths by connecting two quarter-wavelength conversion segments. The signal is then connected to the standard impedance output line (2211). A wide-edge coupling line is designed at the connection, with one end connected to the ground. 2231 represents another quarter-wavelength coupling line between the two couplers. The other end of this coupling line is connected to a circuit with a metallized ground hole (2212). More specifically, the upper copper foil layer 221 of the copper-clad laminate 22 is connected to a Wilkinson power divider via a transmission line. At the intersection of the output ends of the power divider's two quarter-wavelength impedance transformation lines and the output transmission line, a coupled line from a broadside coupler is connected. The coupled transmission line has a line width between 0.2 mm and 5 mm, and a length between 0.5 mm and 200 mm. The other ends of the coupled lines are connected to copper foil grounded via metallized vias or metallized sidewalls of the multilayer laminate. The lower copper foil layer 223 of the copper-clad laminate 22 consists of two coupled lines from the couplers and a back-end power distribution network. The coupling lines on this layer overlap with the coupling lines on the copper foil layer 221. The line width of the coupled lines is between 0.2 mm and 5 mm, and the length is between 0.5 mm and 200 mm. The two coupled lines on this layer are interconnected at the starting end (corresponding to the output line of the power divider on layer 221).

[0023] The copper foil layer 223 containing the circuit is an auxiliary circuit layer, which includes a coupling line circuit and a non-isolated power distribution network. 2232 represents a non-isolated power divider that shares power. The coupling line circuit is two wide-side coupled lines interconnected at one end. The 1-to-2 or 1-to-4 power distribution network has no isolation resistor designed to form a non-isolated power distribution network. If the output power of the coupling line circuit is less than 1W, the ends of the coupling lines of the two wide-side couplers can directly lead the signal lines to the surface layer 211 or 231 through a vertical transition and then weld resistors or connect to the load through a connector. If the output power of the coupling line circuit is greater than 1W, the ends of the coupling lines of the two wide-side couplers can be connected to the non-isolated power distribution network, and the network branch port leads the signal lines to the surface layer 211 or 231 through a vertical transition and then welds resistors or connects to the load through a connector.

[0024] like Figure 3 As shown, the circuit of the copper-clad board 21 of the novel wide-band high-power stripline microwave network application model 1 is composed of a large-area copper layer and is used as a microwave ground.

[0025] like Figure 4 As shown, Figure 1 Layer 2 circuit diagram of the medium- and wide-bandwidth, high-power stripline microwave network application model.

[0026] like Figure 5 As shown, Figure 4 The power divider circuit in the second-layer circuit diagram of a medium- and wide-bandwidth, high-power stripline microwave network application model. The input end of this circuit diagram consists of a standard impedance line connected to two quarter-wavelength impedance transformation sections, which are then connected to standard impedance output lines.

[0027] Figure 6 for Figure 4 The coupling line and the grounding circuit at the end of the coupling line are used for the broadside coupler connected to the main line impedance transformation in the second layer circuit diagram of the medium-wideband high-power stripline microwave network application model.

[0028] Figure 7 for Figure 1 Layer 3 circuit diagram of a medium- and wide-bandwidth, high-power stripline microwave network application model. The other broadside lines of the two couplers are interconnected, with the other ends connected to a power splitter network and a terminal load, respectively.

[0029] Figure 8 for Figure 7 The other broadside coupled line circuit of the coupler in the third layer circuit diagram of the medium-wideband high-power stripline microwave network application model.

[0030] Figure 8 for Figure 7 The other broadside coupled line circuit of the coupler in the third layer circuit diagram of the medium-wideband high-power stripline microwave network application model.

[0031] Figure 9 for Figure 7 The power splitter network circuit connected to the other broadside line of the coupler in the third-layer circuit diagram of the medium- and wide-band high-power stripline microwave network application model.

[0032] Figure 10 for Figure 1 The fourth layer circuit diagram of the medium-wideband high-power stripline microwave network application model is used as the microwave ground.

[0033] Figure 11 This is a simulation model diagram of a broadband high-power stripline microwave network circuit. In the simulation model, the simulation frequency is set to 5GHZ-15GHZ. 21 and 23 use copper clad plates with a thickness of 0.5mm and a dielectric constant of 2.94, and 22 uses copper clad plates with a thickness of 0.1mm and a dielectric constant of 2.94. The circuit uses Figure 5 and Figure 7 shape, where Figure 7 The circuit eliminates the need to share power Figure 9 circuit.

[0034] Figure 12 This figure shows the transmission curve from the main port to the two splitter ports of a broadband, high-power stripline microwave network circuit power splitter. Over the frequency range of 6 GHz to 12.5 GHz, the power splitter's insertion loss is less than 3.25 dB, and the amplitude error between the two output ports is less than 0.05 dB. Within the octave band, the power splitter's performance meets the requirements of conventional engineering applications.

[0035] The present invention provides a broadband, high-power stripline microwave network circuit. By adding a broadside coupler to a conventional single-section Wilkinson power divider, the coupling terminal is connected to a non-isolated power divider network, and the network end is connected to multiple loads, thereby solving the power resistance problem of broadband stripline microwave networks. With a small increase in the size of the main circuit, the operating bandwidth of the single-section power divider is increased from 15% to an octave, and the average power resistance of the network is increased to tens of watts.

[0036] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A broadband high-power stripline microwave network circuit, characterized in that: The method comprises a plurality of base units, wherein the base units include a copper clad plate, a prepreg layer, and a metallized hole; The first copper-clad laminate comprises a first dielectric layer, and the upper surface of the first dielectric layer is covered with a first copper foil layer; The second copper clad laminate comprises a second dielectric layer, and the upper surface and the lower surface of the second dielectric layer are covered with a second copper foil layer and a third copper foil layer; The third copper clad laminate comprises a third dielectric layer, and the lower surface of the third dielectric layer is covered with a fourth copper foil layer; The first copper foil layer to the fourth copper foil layer are etched to form a circuit required for the microwave network; According to the lamination order of a first copper clad laminate, a second copper clad laminate, and a third copper clad laminate, the copper clad laminates are hot-pressed into a multi-layer copper clad laminate by placing a first prepreg layer between the first copper clad laminate and the second copper clad laminate, and placing a second prepreg layer between the second copper clad laminate and the third copper clad laminate; Grounding holes are set on the multi-layer copper clad board and metalized to form metalized grounding holes to achieve microwave ground interconnection between the base copper foils.

2. The broadband high-power stripline microwave network circuit according to claim 1, characterized in that: The first copper foil layer and the fourth copper foil layer are microwave ground layers, which are shielding grounds for microwave network circuits.

3. The broadband high-power stripline microwave network circuit according to claim 1, characterized in that: The second copper foil layer is the main power division network of the microwave network circuit. A transmission line is connected to a Wilkinson power divider. At the intersection of the output end of the two quarter-wavelength impedance transformation lines of the Wilkinson power divider and the output transmission line, one end of the coupling line of a broadside coupler is connected. The other end of the coupling line of the two broadside couplers is connected to the circuit with a metallized grounding hole.

4. The broadband high-power stripline microwave network circuit according to claim 3, characterized in that: The third copper foil layer includes the other end coupling lines of the two broadside couplers and a rear-end power distribution network. The position of the coupling lines of the third copper foil layer overlaps with the position of the coupling lines of the broadside couplers on the second copper foil layer. The two coupling lines of the third copper foil layer are interconnected at the starting end, and the starting end corresponds to the output end of the two quarter-wavelength impedance transformation lines of the Wilkinson power divider on the second copper foil layer.

5. The broadband high-power stripline microwave network circuit according to claim 1, characterized in that: The third copper foil layer is the auxiliary circuit layer, which includes a coupled line circuit and a non-isolated power distribution network. The coupled line circuit is two broadside coupled lines interconnected at one end. The 1-to-2 or 1-to-4 power distribution network has no isolation resistors, forming a non-isolated power distribution network. If the output power of the coupled line circuit is less than 1W, the ends of the coupled lines of the two broadside couplers can be directly led to the first copper foil layer or the fourth copper foil layer through a vertical transition, and then soldered with a resistor or connected to the load through a connector; If the output power of the coupled line circuit is greater than 1W, the ends of the coupled lines of the two broadside couplers can be connected to a non-isolated power distribution network. The network branch port leads the signal line to the first copper foil layer or the fourth copper foil layer through a vertical transition and then solders the resistor or connects the load through a connector.

6. The broadband high-power stripline microwave network circuit according to claim 1, characterized in that: The thickness of the copper clad laminate is 0.025mm~3mm, the thickness of the prepreg layer is 0.025mm~0.2mm, and the thickness of the copper foil layer is 0.009mm~0.036mm.

7. The broadband high-power stripline microwave network circuit according to claim 3 or 4, characterized in that: The width of the coupling line is 0.2mm~5mm, and the length of the coupling line is 0.5mm~200mm.

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