High-power microwave transistor load traction test clamp
By designing a load-pulling test fixture for high-power microwave transistors, the testing challenges of large-size GaN microwave transistors under high-frequency and high-power conditions were solved, enabling accurate RF performance measurement and modeling.
Patent Information
- Application Number
- CN202511510560.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-22
- Publication Date
- 2026-01-13
AI Technical Summary
Existing technologies struggle to accurately test the RF performance of large-size GaN microwave transistors, especially under high-frequency and high-power conditions, leading to inaccurate modeling.
A high-power microwave transistor load traction test fixture was designed, including a printed circuit board, a heat sink, and an RF connector. The chip under test is embedded into the printed circuit board and the boss part by gold soldering, and pre-matching is performed by impedance transformation line. Combined with height adjustment and gold-plated heat sink, high-frequency testing is realized.
It enables high-frequency, high-power testing of large-size microwave transistors, accurately measures saturated output power >100W, supports device modeling and parameter extraction, and improves the accuracy of device modeling.
Smart Images
Figure CN121324701A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of microwave power transistor testing technology, and in particular to a load-pulling test fixture for high-power microwave transistors. Background Technology
[0002] Microwave power amplifiers are key components of radio frequency systems, used at the transmitter end to radiate high power, and are widely used in communications and radar fields. In recent years, GaN… HEMT device technology research is a hot topic in the field of microwave circuits both at home and abroad. Although GaN technology has better frequency characteristics and efficiency indicators than LDMOS technology, GaN substrates are expensive and have material defects and reliability issues. Applying it to the development of microwave RF devices requires accurate device modeling, which in turn requires accurate measurement data. Modeling the continuous wave operating mode of large-size power transistor devices is a challenge.
[0003] Due to the inherent defects of GaN, such as its sensitivity to crystal quality leading to reduced carrier mobility, the need for surface passivation or field plate structures to mitigate current collapse, and its high thermal density resulting in heavy reliance on thermally conductive substrates, accurate modeling of GaN devices is a crucial step in process development. Device modeling typically requires fitting with measured data, and accurate device performance modeling and parameter extraction are of paramount importance. Since the measurement of large-signal parameters is easily affected by factors such as the highest frequency and power capacity of the measurement equipment, the measurement data of small-sized devices is usually scaled to obtain the RF performance of large-sized devices. Although some parameters can be obtained through scaling, the distribution effects, thermal coupling, and cell imbalances of large-sized dies in reality make it difficult to directly calculate using scaling. Summary of the Invention
[0004] To address the issue that testing large-size devices can easily exceed the equipment's maximum frequency and power capacity, this invention proposes a high-power microwave transistor load traction test fixture.
[0005] This invention is achieved through the following technical solution: This invention proposes a high-power microwave transistor load-pulling test fixture comprising a printed circuit board, a heat sink, and an RF connector, wherein: The printed circuit board is mounted on the top surface of the heat sink, and the radio frequency connector includes an input radio frequency connector and an output radio frequency connector, which are respectively connected to both sides of the printed circuit board. The printed circuit board has a test hole, and the heat sink has a boss that is embedded in the test hole. A chip under test is soldered to the top of the boss. The top of the chip under test is at the same height as the printed circuit board, and the chip under test is connected to the printed circuit board.
[0006] Furthermore, the heat sink is provided with height adjustment holes around its perimeter, and the height adjustment holes are connected to adjustment screws, which are used to adjust the height of the heat sink.
[0007] Furthermore, the printed circuit board is directly soldered to the printed circuit board, and the chip under test is soldered to the top of the boss portion.
[0008] Furthermore, it also includes lumped components soldered onto the printed circuit board, the lumped components being used to maintain the stability of the printed circuit board.
[0009] Furthermore, the heat sink is made of brass and its surface is gold-plated.
[0010] Furthermore, the gold plating thickness of the protrusion portion on the surface of the heat sink is >3µm, and the gold plating thickness of the area on the surface of the heat sink other than the protrusion portion is >1.3µm.
[0011] The beneficial effects of this invention are: The high-power microwave transistor load traction test fixture proposed in this invention embeds the chip under test into the printed circuit board and the boss part to test the chip, and can realize the load traction test of devices with saturated output power >100W. Attached Figure Description
[0012] Figure 1 This is a structural diagram of the high-power microwave transistor load traction test fixture of the present invention; Figure 2 This is a structural diagram of the test system for the high-power microwave transistor load traction test fixture of the present invention; Figure 3 This diagram illustrates the impedance tuning range of the high-power microwave transistor load traction test fixture of the present invention. In the diagram: 1. Heat sink; 2. Printed circuit board; 3. Input RF connector; 4. Output RF connector. The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0013] To more clearly and completely illustrate the technical solution of the present invention, the present invention will be further described below with reference to the accompanying drawings.
[0014] Please refer to Figures 1-3 This invention proposes a high-power microwave transistor load traction test fixture, comprising a printed circuit board 2, a heat sink 1, and an RF connector, wherein: The printed circuit board 2 is mounted on the top surface of the heat sink 1. The radio frequency connector includes an input radio frequency connector 3 and an output radio frequency connector 4, which are respectively connected to both sides of the printed circuit board 2. The printed circuit board 2 has a test hole, and the heat sink 1 has a boss. The boss is embedded in the test hole, and the test chip is soldered to the top of the boss. The top of the test chip is at the same height as the printed circuit board 2, and the test chip is connected to the printed circuit board 2.
[0015] In a specific implementation, during testing, the chip under test is first directly soldered onto the structural component using gold-tin eutectic bonding. The printed circuit board 2 is then soldered onto the heat sink 1 using lead-tin bonding. Subsequently, the input RF connector 3 and the output RF connector 4 are connected to the left, right, and rear sides of the printed circuit board 2, respectively. Finally, the test is performed using a test system in the prior art. This invention utilizes the embedding of the chip under test into the printed circuit board 2 and the boss portion to test the chip, enabling load traction testing of devices with saturated output power > 100W.
[0016] In one embodiment, the test system is as follows Figure 2 As shown, the testing system is typically coaxially connected to the entire fixture for testing.
[0017] In one embodiment, to reduce losses and improve high-frequency testing performance, the printed circuit board 2 uses ROGERS4350B material with a total board thickness of 0.6mm. When measuring the chip under test of a high-power device, the input impedance of the device is usually very low, which may exceed the adjustment range of the reflection coefficient of the impedance tuner. Therefore, an impedance transformation line is usually used for pre-matching the device. After introducing the impedance transformation line, the impedance tuning range seen from the device to the source end will shift towards the lower impedance point, such as... Figure 3 As shown in the figure, the gray area represents the region where the tuner cannot be loaded. Although the overall tuning range decreases from region 1 to region 2, it covers the low impedance region.
[0018] Furthermore, the heat sink 1 is provided with height adjustment holes around its perimeter, and the height adjustment holes are connected to adjustment screws, which are used to adjust the height of the heat sink 1.
[0019] In a specific implementation, in order to ensure that the test impedance range is large enough, the printed circuit board 2 and the RF connector are directly hard-connected. In order to ensure that the RF connector is not damaged, the threaded ends of the four adjusting screws are used to connect the adjustment holes, and the other end is used to support the bottom surface. The height of the heat sink 1 (the entire fixture) is adjusted to adapt to the height of the RF connector.
[0020] Furthermore, the printed circuit board 2 is directly soldered to the printed circuit board 2, and the chip under test is soldered to the top of the boss.
[0021] In a specific implementation, the printed circuit board 2 is first soldered to the heat sink 1, and then the chip to be tested is first soldered to the boss using gold solder. This is because there is a large temperature gradient between gold soldering and lead-tin soldering, so an improper sequence may cause a reduction in the soldering quality of the printed circuit board 2.
[0022] Furthermore, it also includes lumped components soldered onto the printed circuit board 2, which are used to maintain the stability of the printed circuit board 2.
[0023] In a specific implementation, the integrated components include devices such as resistors and inductors disposed on the printed circuit board 2. These are necessary peripheral devices for stable operation. The integrated components can be used to complete low-frequency decoupling of the chip under test.
[0024] Furthermore, the heat sink 1 is made of brass, and the surface of the heat sink 1 is gold-plated. The gold plating thickness of the protrusions on the surface of the heat sink 1 is >3µm, and the gold plating thickness of the area on the surface of the heat sink 1 other than the protrusions is >1.3µm.
[0025] In a specific implementation, after gold plating, lead-tin solder can be used for welding, and the size of the heat sink 1 is related to the size of the printed circuit board 2.
[0026] Of course, the present invention may have many other embodiments. Based on this embodiment, other embodiments obtained by those skilled in the art without any creative effort are all within the scope of protection of the present invention.
Claims
1. A high-power microwave transistor load traction test fixture, characterized in that, This includes printed circuit boards, heat sinks, and RF connectors, among which: The printed circuit board is mounted on the top surface of the heat sink, and the radio frequency connector includes an input radio frequency connector and an output radio frequency connector, which are respectively connected to both sides of the printed circuit board. The printed circuit board has a test hole, and the heat sink has a boss that is embedded in the test hole. A chip under test is soldered to the top of the boss. The top of the chip under test is at the same height as the printed circuit board, and the chip under test is connected to the printed circuit board.
2. The high-power microwave transistor load traction test fixture according to claim 1, characterized in that, The heat sink is provided with height adjustment holes around its perimeter, and adjustment screws are connected to the height adjustment holes. The adjustment screws are used to adjust the height of the heat sink.
3. The high-power microwave transistor load traction test fixture according to claim 1, characterized in that, The printed circuit board is directly soldered to the printed circuit board, and the chip under test is soldered to the top of the boss.
4. The high-power microwave transistor load traction test fixture according to claim 3, characterized in that, It also includes lumped components soldered onto the printed circuit board, which are used to maintain the stability of the printed circuit board.
5. The high-power microwave transistor load traction test fixture according to claim 2, characterized in that, The heat sink is made of brass and its surface is gold-plated.
6. The high-power microwave transistor load traction test fixture according to claim 5, characterized in that, The gold plating thickness of the protrusions on the surface of the heat sink is >3µm, and the gold plating thickness of the area on the surface of the heat sink other than the protrusions is >1.3µm.