An integrated module design of radar power supply and wave control

Abstract

An integrated module design of radar power supply and wave control, dividing the area layout of power supply circuit and wave control circuit, adopting LTCC process design for ceramic substrate, designing printed circuit layout, determining the size of ceramic substrate and metal shell, bonding surface-mounted devices to the corresponding position of the front, bonding pins to the corresponding position of the back, bonding the back of the ceramic substrate to the internal floor of the metal shell, using reflow soldering process to simultaneously solder, then testing and cleaning, setting interconnection bonding pads bonding gold wire or aluminum wire at the front end of the power supply inlet of the wave control circuit, welding the cover plate and the shell in an inert gas environment, and testing the electrical performance of the integrated module, checking the air tightness, checking the excess, and related environmental testing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radar power supply and wave control module, and particularly relates to an integrated design technology. BACKGROUND

[0002] With the continuous improvement of the sensitivity, action distance and imaging accuracy of synthetic aperture radar (SAR), the functions and modes of the antenna system also need to be continuously developed. The power supply unit provides power supply for the radar antenna, and the wave control unit provides beam control for the radar antenna, both of which play a crucial role in the antenna system.

[0003] The power supply unit converts the power provided by the solar panel or the battery pack into the direct current low voltage required by the radar transceiver assembly through power conversion, and provides reliable pulse energy under the working conditions of radar pulse change or switching. The wave control unit performs wave control code calculation and control according to the usage mode instruction, completes the corresponding component control according to the transmitting and receiving states, and collects and returns the monitoring signals such as power supply voltage and temperature.

[0004] With the development of communication, computer, microelectronics and other technologies, radar technology has developed rapidly, and higher requirements are put forward for the power supply unit and the wave control unit. High efficiency, high power, high speed and high reliability are one of the requirements, and thinning is also a demand direction of the radar antenna. The power supply unit and the wave control unit not only need to realize their own lightweight, but also need to reduce the height of the single machine to adapt to the thinning requirements of the radar antenna.

[0005] The common design method on the radar antenna array surface is to design the power supply and the wave control as two single machines, and the power supply and the signal interconnection between the two single machines are realized through the connector and the connecting cable. The volume, weight and mounting method of the two single machines occupy a certain area of the radar antenna array surface, and the output connector and the connecting cable of the single machine also occupy a certain space. In order to further reduce the volume and weight of the radar antenna, the power supply and the wave control fusion design method is adopted to further improve the integration of the single machine and adapt to the development needs of the radar antenna array surface technology. SUMMARY

[0006] In order to solve the problems existing in the prior art, the application provides a radar power supply and wave control integrated module design. In order to achieve the above purpose, the application adopts the following technical scheme.

[0007] The module includes a metal shell, a cover plate, a pin, and an internal circuit board, the internal circuit board includes a ceramic substrate, a power supply circuit and a wave control circuit, the power supply circuit and the wave control circuit are designed on the ceramic substrate, and the power supply voltage, power conversion, wave control code calculation, control and signal telemetry are realized.

[0008] Step one: according to the voltage spacing requirements of the power supply circuit, the functional performance requirements and the functional performance requirements of the wave control circuit, select the components, divide the area layout of the power supply circuit and the wave control circuit, and avoid mutual interference between the power supply circuit and the wave control circuit.

[0009] Further, the power devices, semiconductor devices and analog integrated devices of the power supply circuit adopt bare chips, and the resistors, capacitors and magnetic devices adopt finished devices. According to the size of the input voltage and current of the power supply, the size of the output voltage and current, and the type of signal, 72 pins are selected as the connection terminals of the input and output. The digital integrated devices and analog integrated devices of the wave control circuit adopt bare chips, and the resistors and capacitors adopt finished devices. According to the control scale and the number of signals of the wave control, 132 pins are selected as the connection terminals of the input and output. The use of bare chips saves packaging area and weight.

[0010] Step two: the ceramic substrate is designed by LTCC process, and the power supply circuit wiring power layer, signal layer and ground layer and the wave control circuit power supply layer, signal layer and ground layer are distinguished in the internal substrate.

[0011] Further, the power supply outputs +9V / 8.5A, +3.3V / 6A and -3.3V / 0.5A three voltages, and the power supply layer and power ground layer of +9V, the power supply layer and power ground layer of +3.3V, and the power supply layer and power ground layer of -3.3V are arranged in layers.

[0012] Step three: based on the selection and packaging size of components, the size of the ceramic substrate and the design specification of LTCC, the printed circuit layout is designed, including the printed pattern lines of the front, back and middle layers and the via holes between the connection layers.

[0013] Step four, the four edges of the ceramic substrate and the inner side wall of the metal shell are kept with a mounting spacing, the devices of the ceramic substrate and the cover plate are kept with a mounting spacing, and the side of the metal shell in the length direction is designed with four mounting fixing holes for fixing the module to other equipment.

[0014] Further, the area of the ceramic substrate is 77mm×57mm, and the thickness is 2mm. The mounting spacing between the four edges of the ceramic substrate and the inner side wall of the metal shell is 0.5mm. The thickness of the side wall of the metal shell is 1mm. The outer shape length and width is 80mm×60mm. The thickness of the bottom mounting surface is 2mm. The thickness of the cover plate is 1.5mm. The highest device of the ceramic substrate is 8mm. The mounting spacing between the highest device and the cover plate is 0.5mm. The height of the metal shell is 14mm. The metal shell is made of aluminum-silicon alloy material, which has good strength and thermal conductivity, and is convenient for processing.

[0015] Step five: according to the printed patterns on the front and back of the ceramic substrate, a screen is made, solder is brushed on the front and back of the ceramic substrate according to the screen, the surface-mounted device is bonded to the corresponding position on the front, the pin is bonded to the corresponding position on the back, the part of the metal shell corresponding to the pin is milled to be hollow to facilitate the pin to extend out of the shell, the back of the ceramic substrate is bonded to the inner bottom plate of the metal shell, and then reflow soldering process is adopted to simultaneously solder and burn, and then inspection and cleaning are performed.

[0016] Step six: bonding the bare chip, interconnection bonding pads are arranged at the front end of the power supply inlet of the wave control circuit, the power supply circuit and the wave control circuit are disconnected during debugging, gold wire is bonded on the interconnection bonding pads after the power supply circuit is tested to be normal, and then the wave control circuit and the associated circuit are tested.

[0017] Further, the bare chip of the semiconductor device, the analog integrated device and the digital integrated device is bonded by gold wire with a diameter of 25 μm, the bare chip of the power device is bonded by aluminum wire with a diameter of 125 μm, and multiple aluminum wires or gold wires are used for parallel bonding at key positions to improve the reliability of interconnection.

[0018] Step seven: welding the cover plate and the shell in an inert gas environment, and performing electrical performance testing, air tightness inspection, excess material inspection and related environmental testing on the integrated module.

[0019] The power supply circuit and the wave control circuit share the same ceramic substrate layout component, the interconnection is simple and convenient, the signal connection line is shorter, the area of the integrated module is reduced, the volume of the integrated module is reduced, the low-temperature co-fired ceramic technology is used for design, the multilayer wiring and layered layout of the electrical pattern are facilitated, and the production cost is low; the aluminum-silicon alloy is used as the material of the metal shell to realize the lightweight of the integrated module; the component uses the bare chip form, and the micro-assembly process is combined to realize the miniaturization of the module. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a module appearance view, Figure 2 is a module sectional view, Figure 3 is a front layout view, Figure 4 is a back layout view.

[0021] The drawings show that: 1 is a module, 2-1 is a cover plate, 2-2 is a side wall, 2-3 is a mounting surface, 3-1 is a power pin, 3-2 is a wave control pin, 4 is a mounting fixing hole, 5 is a ceramic substrate, 6 is a power bare chip, 7 is a wave control bare chip, 8 is a finished device, 9 is an interconnection bonding pad, 10 is an aluminum wire, 11 is a gold wire, 12 is a power pin pad, 13 is a wave control pin pad, and 14 is a ceramic substrate pad. DETAILED DESCRIPTION

[0022] The technical solutions of the present application are described in detail below with reference to the drawings.

[0023] Module 1 includes a metal shell, a cover plate, a pin, an internal circuit board, and mounting holes 4 around the perimeter, as shown. Figure 1 As shown, the cover plate 2-1 and the side wall 2-2 of the metal shell are finally welded to form a cavity, which contains the internal circuit board, including a ceramic substrate 5, as shown. Figure 2 As shown, the finished device 8 is welded to its front face, and the power pin 3-1 and the wave control pin 3-2 are welded to its back face.

[0024] The power supply circuit uses a power bare chip 6, and the wave control circuit uses a wave control bare chip 7, which are welded to the front face of the ceramic substrate 5. Interconnection bonding pads 9 are provided at the front end of the power supply inlet of the wave control circuit, as shown. Figure 3 As shown, the bare chips of semiconductor devices, analog integrated devices, and digital integrated devices are bonded with gold wires 11, and the bare chips of power devices are bonded with aluminum wires 10, as shown. Figure 2

[0025] The back face of the ceramic substrate 5 is made of a screen, and power pin pads 12 and wave control pin pads 13 are provided, as shown. Figure 4 As shown, the part of the metal shell corresponding to the pin is milled to be hollow, which facilitates the pin to extend out of the shell. The back face of the ceramic substrate 5 is bonded to the internal bottom plate of the mounting surface 2-3 of the metal shell through the ceramic substrate pads 14, as shown. Figure 1

[0026] The above is an embodiment of the present application, which does not limit the present application. Any modification, equivalent replacement, and improvement within the spirit and principles of the present application are included in the protection scope of the present application.​​

Claims

1. An integrated module design for radar power supply and beam control, characterized in that, include: The metal casing, cover plate, pins, and internal circuit board include a ceramic substrate, power supply circuit, and wave control circuit. The power supply circuit and wave control circuit are designed on the same board on the ceramic substrate to realize the conversion of power supply voltage and power, as well as wave control code calculation, deployment, and signal telemetry. Step 1: Select components based on the voltage spacing requirements, functional performance requirements of the power supply circuit and the functional performance requirements of the wave controller circuit, and divide the layout of the power supply circuit and the wave controller circuit to avoid mutual interference between them; select 72 pins as input and output connection terminals according to the magnitude of the power supply input voltage and current, the magnitude of the output voltage and current, and the type of signal; use bare chips for the digital and analog integrated devices of the wave controller circuit, and use finished components for resistors and capacitors; select 132 pins as input and output connection terminals according to the control scale and number of signals of the wave controller. Step 2: The ceramic substrate is designed using LTCC technology. Inside the substrate, the power layer, signal layer, and ground layer for power circuit wiring are separated, as well as the power supply layer, signal layer, and ground layer for wave control circuit. The power output has three voltages: +9V / 8.5A, +3.3V / 6A, and -3.3V / 0.5A. The +9V power supply layer and power ground layer, the +3.3V power supply layer and power ground layer, and the -3.3V power supply layer and power ground layer are arranged in layers. Step 3: Based on the selection and package size of components, the size of the ceramic substrate, and the design specifications of LTCC, design the printed circuit layout, including the printed pattern lines of the front, back, and intermediate layers, and the vias connecting the layers. Step 4: The ceramic substrate and the inner wall of the metal housing are kept at a mounting distance. The devices on the ceramic substrate and the cover plate are kept at a mounting distance. Four mounting holes are designed on the side of the metal housing along its length for fixing the module to other devices. Step 5: Create a screen printing pattern based on the printed patterns on the front and back of the ceramic substrate. Apply solder to the front and back of the ceramic substrate according to the pattern screen printing pattern. Attach the surface mount devices to the corresponding positions on the front and the pins to the corresponding positions on the back. Mill out the corresponding pins in the metal housing to facilitate the pins to protrude from the housing. Attach the back of the ceramic substrate to the inner base plate of the metal housing. After reflow soldering, inspect and clean the components. Step Six: Bonding bare chips. Interconnect bonding pads are set at the power supply input front of the wave control circuit. During debugging, the power supply circuit and wave control circuit are disconnected. After the power supply circuit is tested and found to be normal, gold wires are bonded onto the interconnect bonding pads. Then, the wave control circuit and its associated circuits are tested. Bare chips of semiconductor devices, analog integrated devices, and digital integrated devices are bonded using 25µm diameter gold wires, while bare chips of power devices are bonded using 125µm diameter aluminum wires. Multiple aluminum or gold wires are used in parallel bonding in critical areas to improve interconnect reliability. Step 7: Weld the cover plate and housing in an inert gas environment, and perform electrical performance testing, airtightness inspection, foreign matter inspection, and relevant environmental tests on the integrated module.

2. The integrated module design for radar power supply and beam control according to claim 1, characterized in that, Step one includes: using bare chips for power devices, semiconductor devices, and analog integrated devices in the power supply circuit, and using finished devices for resistors, capacitors, and magnetic devices. Using bare chips saves packaging area and weight.

3. The integrated module design for radar power supply and beam control according to claim 1, characterized in that, Step four includes: the ceramic substrate has an area of ​​77mm × 57mm and a thickness of 2mm; the mounting distance between the four edges of the ceramic substrate and the inner sidewall of the metal shell is 0.5mm; the sidewall thickness of the metal shell is 1mm; the overall dimensions are 80mm × 60mm; the thickness of the bottom mounting surface is 2mm; the thickness of the cover plate is 1.5mm; the maximum height of the device on the ceramic substrate is 8mm; the mounting distance between the maximum device and the cover plate is 0.5mm; the height of the metal shell is 14mm; and it is made of aluminum-silicon alloy, which has good strength and thermal conductivity and is easy to process.

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