A design method of a miniaturized down-conversion assembly

Abstract

This invention discloses a design method for a miniaturized downconverter component, involving the modeling of active and passive components in RF circuits, as well as system-level modeling and simulation requirements. The simulation is challenging. Based on three-dimensional electromagnetic field simulation and schematic circuit simulation, this invention innovatively performs accurate simulation modeling of the active and passive components and PCB S-parameters of the miniaturized downconverter component. The innovation lies in establishing simulation models of the bonding wires and three-port mixers from the micro-assembly process, adding them to the system-level simulation model. Using the method of moments, the bonding wires, active and passive components are connected to the discrete ports of the PCB to obtain the joint field-circuit simulation results, namely gain, noise figure, and P. ‑1 The combined field-circuit simulation curves allow for precise analysis of miniaturized frequency converter components before physical fabrication.

Description

Technical Field

[0001] This invention belongs to the field of microwave circuits for radar receivers and discloses a design method for a miniaturized downconversion component. Background Technology

[0002] Downconversion components can perform downconversion, attenuation, filtering, amplification, power division, and detection comparison processing on radio frequency signals to output intermediate frequency signals that meet the requirements. They are widely used in satellite communications and radar.

[0003] Traditional downconverter component design methods rely on experience. The design and manufacturing of the physical component are started by simply calculating the gain index. The component thickness is 12mm or even thicker. When the designer tests the downconverter component, he finds that the measured results are inconsistent with the technical specifications, and then it is reworked.

[0004] With the development of radar receivers, downconversion components are becoming smaller and more integrated, which makes signal crosstalk, electromagnetic compatibility issues such as signal line crossings and crossovers more prominent.

[0005] The original design method relied solely on engineering experience to design and then manufacture the physical object. If the physical object test results did not meet the requirements, the equipment would be reworked, wasting manpower, time, and component costs. The designers' work efficiency was low, and they had to work overtime. This was because when designing components, the designers only simulated the schematic diagram and did not perform three-dimensional electromagnetic field simulation modeling of the PCB and structure of the downconverter component. Furthermore, they did not perform system-level modeling and simulation of the active and passive components and PCB S-parameters in the RF circuit. Summary of the Invention

[0006] This invention proposes a design method for a miniaturized downconversion component, which adopts micro-assembly technology to meet the various requirements of radar receivers for radio frequency signals.

[0007] The technical solution for achieving the present invention is: a design method for a miniaturized downconverter component, comprising the following steps:

[0008] S1: Based on the technical specifications of the downconversion component in the radar receiver, formulate a scheme block diagram for the downconversion component, and proceed to step S2.

[0009] The downconversion component includes an RF link, a LO link, a mixer, and an IF link. The RF link is used to attenuate the power of the received radio frequency signal. The LO link attenuates and amplifies the LO signal to provide the LO input signal required by the mixer. The IF link mainly filters, amplifies, attenuates, digitally controls attenuation, and power divides the 750MHz IF signal output from the downconversion to output a processed IF signal, while also performing fault detection on the IF signal.

[0010] S2: Design the schematic diagram based on the scheme block diagram, and obtain the schematic diagram simulation model based on the schematic diagram, then proceed to step S3.

[0011] S3: Based on the simulation results of the downconverter component's schematic diagram, perform PCB design and structural design for the component, then proceed to step S4.

[0012] S4: Based on the PCB and structural design of the downconverter component, design a three-dimensional electromagnetic field simulation model, obtain the three-dimensional electromagnetic field simulation results, and proceed to step S5.

[0013] S5: Based on the three-dimensional electromagnetic field simulation results of the downconverter component, perform field-circuit joint simulation modeling of the component to obtain the field-circuit joint simulation results, and then proceed to step S6.

[0014] S6: Based on the field-circuit joint simulation results of the downconverter component, fabricate a physical prototype of the downconverter component.

[0015] Compared with existing technologies, the significant advantages of this invention are as follows: Compared with traditional downconversion components, this invention adopts micro-assembly technology, reducing the size by 23.08%. It can perform downconversion, attenuation, filtering, amplification, power division, and detection comparison processing on radio frequency signals, outputting an intermediate frequency signal that meets the requirements of radar receivers for radio frequency signals. The field-circuit joint simulation results are consistent with the measured results, providing guidance for the design of radar receivers. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the design methodology for downconverter components.

[0017] Figure 2 This is a block diagram of the downconverter component.

[0018] Figure 3 This is the microwave circuit schematic diagram of the downconverter component.

[0019] Figure 4 This is a schematic diagram of the power-on and control of the downconverter component.

[0020] Figure 5 This is a simulation model of the schematic diagram of the downconverter component.

[0021] Figure 6 This is the PCB diagram of the downconverter component.

[0022] Figure 7 This is a structural diagram of the downconverter component.

[0023] Figure 8 It is a three-dimensional electromagnetic field simulation model of the downconverter component.

[0024] Figure 9 It is a joint simulation model of the field circuit of the downconverter component. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; "connection" can mean a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible to those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0029] The following section will further introduce the specific implementation method, as well as the technical difficulties and inventive points of this invention, using this design example as an example.

[0030] In this invention, the selection of components is strictly controlled within a box structure with a limited size of 80mm×30mm×10mm. The box length is reduced from the original 104mm to 80mm. Due to the requirement for miniaturized frequency converter components to have a small design volume, signal crosstalk and electromagnetic compatibility issues related to signal line crossings are relatively prominent. Based on schematic circuit simulation, this invention performs three-dimensional electromagnetic field simulation modeling on the box and PCB board of the miniaturized frequency converter component, and obtains the S-parameter simulation results of the discrete ports of the PCB.

[0031] Combination Figure 1 The design method of a miniaturized downconverter component according to the present invention comprises the following steps:

[0032] S1: Based on the technical specifications of the down-conversion component in the radar receiver, a block diagram of the proposed solution for the down-conversion component is shown below. Figure 2 As shown.

[0033] The downconversion component includes an RF link, a LO link, a mixer, and an IF link. The main function of the RF link is to attenuate the power of the received RF signal; the main function of the LO link is to attenuate and amplify the LO signal to provide the LO input signal required by the mixer; the main function of the IF link is to filter, amplify, attenuate, digitally control attenuate, and power divide the 750MHz IF signal output from the downconversion, and output the processed IF signal, while also enabling fault detection of the IF signal.

[0034] S2: Design the schematic diagram based on the scheme block diagram, as follows: Figures 3-4 As shown, the schematic simulation model is obtained based on the schematic diagram. Figure 5 As shown.

[0035] The RF link includes one 3dB attenuator BW095 from the 13th Research Institute. The LO link includes one attenuator BW095 from the 13th Research Institute, one amplifier WFD060180-L15 from the 55th Research Institute, and one attenuator BW098 from the 13th Research Institute. The gain of the LO link amplifier is 20dB, and the overall gain of the LO link is 15.5dB, amplifying the LO input signal power from -2.5dBm to the LO input power of 13dBm required by the mixer. The mixer, the core component of the downconverter, is a mixer BW377 from the 13th Research Institute.

[0036] The IF link includes six attenuators (BW095, BW098, and BW105) from the 13th Research Institute, three amplifiers (BW193), one power divider (BW490), and one digitally controlled attenuator (BW163); two LTCC filters (LTB750-260-6M from Hefei Bolun); and one HKM9037G from Chengdu Hongming. The two cascaded LTCC filters meet the IF out-of-band rejection (IF) technical requirements for the frequency converter channel: ≥60dBc@DC~420MHz and ≥60dBc@1050~4000MHz.

[0037] S3: Based on the simulation results of the down-converter component's schematic diagram, design the PCB for this component as follows: Figure 6 As shown, and the structural design as follows Figure 7 As shown.

[0038] S4: Based on the PCB and structural design of the downconverter component, perform a three-dimensional electromagnetic field simulation model, such as... Figure 8 As shown, the three-dimensional electromagnetic field simulation results are obtained.

[0039] In the three-dimensional electromagnetic field simulation model, a transient solver and a hexahedral meshing method are employed. The innovation lies in the localized refinement of the 0.035mm thick copper layer of the down-converter component. The simulation model also incorporates the down-converter component's housing structure, thereby achieving accurate three-dimensional electromagnetic field simulation of the down-converter component. Based on schematic circuit simulation, this invention performs three-dimensional electromagnetic field simulation modeling of the down-converter component's housing and PCB board, obtaining the S-parameter simulation results for the discrete ports of the PCB.

[0040] S5: Based on the three-dimensional electromagnetic field simulation results of the downconverter component, perform field-circuit joint simulation modeling of the component to obtain the field-circuit joint simulation results.

[0041] The challenge lies in the involvement of RF circuit gold wires, active devices, passive devices, and system-level modeling and simulation requirements, making the simulation difficult. The innovation lies in incorporating the bonding gold wires and three-port mixer simulation models from the micro-assembly process into the system-level simulation model. The method of moments is used to connect the gold wires, active devices, passive devices, and discrete ports on the PCB. This invention, based on 3D electromagnetic field simulation and schematic circuit simulation, performs field-circuit joint simulation modeling of the downconverter component, as follows: Figure 9 The field-path joint simulation results are obtained, namely gain, noise figure, and P. -1 Field-circuit joint simulation curves.

[0042] S6: Based on the field-circuit joint simulation results of the downconverter component, fabricate a physical prototype of the downconverter component.

[0043] The RF, LO, and IF input / output connectors use RF connectors from Xi'an Elite, ensuring a hermetically sealed design for the components. The power-on control connector uses a rectangular connector from Xi'an Elite.

[0044] The interface network labels and functions of the rectangular connector are shown in Table 1. It is powered by +6V and -5V. The control bits of the digitally controlled attenuator are controlled by parallel code, namely BW163_V1~BW163_V6, which control the 0.5dB, 1dB, 2dB, 4dB, 8dB and 16dB attenuation control bits of the digitally controlled attenuator BW163 in the IF link, respectively.

[0045] Table 1 Interface Network Numbers and Functions of Rectangular Connectors

[0046] Terminal number Network label Function 1 BW163_V4 4dB control position of CNC attenuator 2 -5V -5V power supply 3 BW163_V5 8dB control position of CNC attenuator 4 BW163_V1 0.5dB control position of CNC attenuator 5 VT2 Broadband detection module detects 2 reference points 6 TTL1 Broadband detector module output 1 7 +6V +6V power supply 8 AGND Simulated land 9 BW163_V6 16dB control position of digital attenuator 10 -5V -5V power supply 11 BW163_V3 2dB control position of CNC attenuator 12 BW163_V2 1dB control position of CNC attenuator 13 TTL2 Broadband detector module output 2 14 VT1 Broadband detector module test reference point 1 15 +6V +6V power supply

[0047] The downconverter component in this invention has dimensions of 80mm × 30mm × 10mm and a weight of 48.7g.

[0048] In this invention, the mixer is a three-port device. Existing field-circuit co-simulation modeling used typical values ​​for the component in the mixer model, which slightly differed from the measured results. This was because the manufacturer provided two-port S-parameter files, namely S2P and S1P files. This invention innovatively uses the DataAccessComponent function, combined with the S3P_Eqn module, to connect the mixer's S2P and S1P files, achieving three-port component modeling and simulation.

[0049] The miniaturized downconverter component of this invention measures 80mm × 30mm × 10mm and weighs 48.7g. Compared to traditional downconverter components, the downconverter component of this invention reduces its volume by 23.08%, meeting the miniaturization requirements of radar receiver microwave subsystems.

[0050] This invention utilizes micro-assembly technology to realize a miniaturized downconverter component, which has the advantages of miniaturization, high reliability, high integration and strong versatility, and has a wide range of engineering applications.

Claims

1. A design method for a downconverter component, characterized in that, The steps are as follows: S1: Based on the technical specifications of the downconversion component in the radar receiver, formulate a scheme block diagram for the downconversion component, and proceed to step S2. The downconversion component includes an RF link, a LO link, a mixer, and an IF link. The RF link is used to attenuate the power of the received radio frequency signal. The LO link attenuates and amplifies the LO signal to provide the LO input signal required by the mixer. The IF link mainly filters, amplifies, attenuates, digitally controls attenuation, and power divides the 750MHz IF signal output from the downconversion to output a processed IF signal, while also performing fault detection on the IF signal. The downconverter assembly is confined within a housing structure with dimensions of 80mm × 30mm × 10mm; S2: Design the schematic diagram based on the scheme block diagram, and construct the schematic diagram simulation model based on the schematic diagram to obtain the schematic diagram simulation results, then proceed to step S3; S3: Based on the simulation results of the downconverter component's schematic diagram, perform PCB design and structural design for the component, then proceed to step S4; S4: Based on the PCB and structural design of the downconverter component, design a three-dimensional electromagnetic field simulation model, obtain the three-dimensional electromagnetic field simulation results, and proceed to step S5. S5: Based on the three-dimensional electromagnetic field simulation results of the downconverter component, perform field-circuit joint simulation modeling of the component to obtain the field-circuit joint simulation results, and proceed to step S6. S6: Based on the field-circuit joint simulation results of the downconverter component, perform physical fabrication of the downconverter component.

2. The design method of the down-conversion component according to claim 1, characterized in that, In S2, the schematic diagram is designed based on the scheme block diagram, and a schematic simulation model is constructed based on the schematic diagram to obtain the schematic simulation results, as follows: The RF link includes one 3dB attenuator BW095; the LO link includes one attenuator BW095, one amplifier WFD060180-L15, and one attenuator BW098. The gain of the LO link amplifier is 20dB, and the overall gain of the LO link is 15.5dB, amplifying the LO input signal power from -2.5dBm to the LO input power of 13dBm required by the mixer; the mixer, a core component of the downconverter, is a BW377 mixer. The IF link includes 6 attenuators BW095, 1 attenuator BW098, 1 attenuator BW105, 3 amplifiers BW193, 1 power divider BW490, 1 digitally controlled attenuator BW163, 2 LTCC filters LTB750-260-6M, and 1 HKM9037G. The two stages of LTCC filters are cascaded to meet the IF out-of-band rejection technical requirements of the frequency converter channel: ≥60dBc@DC~420MHz, ≥60dBc@1050~4000MHz.

3. The design method of the down-conversion component according to claim 2, characterized in that, In S4, based on the PCB and structural design of the downconverter component, a three-dimensional electromagnetic field simulation model is designed, and the three-dimensional electromagnetic field simulation results are obtained as follows: In the three-dimensional electromagnetic field simulation model, a transient solver and a hexahedral meshing method are used to locally refine the 0.035mm thick copper layer of the downconverter component. The downconverter component box structure is also added to the simulation model to achieve accurate three-dimensional electromagnetic field simulation of the downconverter component. Based on the schematic circuit simulation, a three-dimensional electromagnetic field simulation model was performed on the housing and PCB board of the downconverter component to obtain the S-parameter simulation results of the discrete ports of the PCB.

4. The design method of the down-conversion component according to claim 3, characterized in that, In S5, based on the three-dimensional electromagnetic field simulation results of the downconverter component, a field-circuit joint simulation model is performed on the component to obtain the field-circuit joint simulation results, as follows: The bonding wires and three-port mixer in the micro-assembly process are simulated and modeled, and added to the system-level simulation model. The bonding wires, active devices, passive devices and discrete ports of the PCB are connected by the method of moments. Based on three-dimensional electromagnetic field simulation and schematic circuit simulation, a field-circuit joint simulation model of the downconverter component is performed to obtain the field-circuit joint simulation results, namely gain, noise figure, and P. -1 Field-circuit joint simulation curves.

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