A wideband TEM cell for EMC testing of integrated circuits

Abstract

The application discloses a kind of wideband TEM small room for integrated circuit EMC test, and body includes oppositely arranged first shell and second shell, wherein, installation cavity is formed between first shell and second shell;Installation cavity is used to install core plate;After first shell and second shell are oppositely arranged, first connector and second connector are respectively installed at both ends of body;The inside side wall of installation cavity formed by first shell and second shell transversely spliced has waveguide gradual change surface compatible with core plate.The application is symmetrical by one hundred and eighty degrees rotation of split structure, so that first shell and second shell are completely identical as general monomer parts, and only one part drawing and a set of processing procedures are needed when mass production.

Description

Technical Field

[0001] This invention relates to a broadband TEM chamber, and more particularly to a broadband TEM chamber for EMC testing of integrated circuits. Background Technology

[0002] Transverse electromagnetic wave chambers (TEM chambers) are key equipment for electromagnetic compatibility (EMC) testing of integrated circuits, widely used in high-precision testing of radiated emissions and radiated immunity. Traditional TEM chambers generally employ a split structure with different upper and lower cavities, typically assembled from upper and lower chambers of varying shapes and sizes. A waveguide space is formed within each cavity to establish a standard uniform electromagnetic field. Furthermore, to establish a stable high-frequency transmission channel in the core testing area, the central core board inside the traditional TEM chamber is often welded to the coaxial high-frequency connectors at both ends for input / output of high-frequency signals using traditional heat welding processes. This ensures the closure of the electromagnetic boundary and the electrical connection of the signal.

[0003] However, the aforementioned existing technical solutions have significant defects and shortcomings in actual processing, assembly, and high-frequency operating conditions: First, in terms of machining and assembly, because the shapes and dimensions of the upper and lower cavities are not interchangeable, CNC machining programs must be independently developed for two different parts during mass production, and two completely independent process benchmarks must be used for CNC machining. This results in an extremely cumbersome overall machining process, and the alignment accuracy of the upper and lower parts is poor during assembly, with a very low assembly error tolerance, making it impossible to guarantee precise geometric consistency between batch products, leading to high production and processing costs. Second, in terms of high-frequency electromagnetic performance, the high-frequency band has stringent requirements on the flatness of the transmission channel surface at the micrometer level. However, existing welding processes are prone to producing defects such as uneven local weld points, residual weld beads, and deformation of the cavity or core board structure caused by high temperatures. These defects directly cause abrupt changes in the distributed capacitance and distributed inductance of the high-frequency signal transmission interface, resulting in a severe discontinuity shift in characteristic impedance. This, in turn, excites extremely large signal reflections under high-frequency operating conditions, leading to a sharp increase in insertion loss, severely deteriorating the high-frequency VSWR, and narrowing the test bandwidth. Meanwhile, the uneven conductive interface can also cause distortion of the distribution of high-frequency electromagnetic field inside the cavity, resulting in a significant decrease in test accuracy. In addition, since the welded structure is non-removable, once the internal components are slightly damaged or shifted, subsequent debugging, replacement of spare parts and repeated calibration will become extremely difficult, which can easily cause irreversible damage to the overall structure of the chamber, resulting in extremely poor product consistency and reusability. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a wideband TEM chamber for EMC testing of integrated circuits, which solves the problems of traditional TEM chambers with separate upper and lower parts, which are not universally compatible, resulting in complicated processing, poor assembly and alignment accuracy, and the fact that the welding process of components is prone to causing interface impedance mismatch, high-frequency standing wave deterioration, electromagnetic field distortion, and the inability to disassemble and maintain them in the later stage.

[0005] The technical problem to be solved by this invention is achieved by the following technical solution: This invention provides a wideband TEM chamber for EMC testing of integrated circuits, the main body comprising a first housing and a second housing disposed opposite to each other, wherein, An installation cavity is formed between the first housing and the second housing; The mounting cavity is used to mount the core board; After the first housing and the second housing are positioned opposite each other, a first connector and a second connector are respectively installed at both ends of the main body; The mounting cavity formed by the horizontal assembly of the first housing and the second housing has a waveguide gradient surface on its inner sidewall that is compatible with the core plate.

[0006] As a preferred embodiment of the present invention, both the first housing and the second housing are provided with a mounting groove on one side; The mounting slot is used to place the cover plate, wherein... The cover plate is provided with through holes for engaging the first fastener.

[0007] As a preferred embodiment of the present invention, the first connector and the second connector disposed at both ends of the body are both connected to the body by a third fastener.

[0008] As a preferred embodiment of the present invention, the mounting grooves of the first housing and the second housing have bosses, and the bosses are provided with first mounting holes.

[0009] In a preferred embodiment of the present invention, both the first housing and the second housing have a plurality of second mounting holes on opposite sides. The first housing and the second housing are connected by a second fastener passing through the second mounting hole.

[0010] As a preferred embodiment of the present invention, the end plates of the first connector and the second connector are each provided with a third mounting hole for mounting the first connector and the second connector to the first housing or the second housing.

[0011] As a preferred embodiment of the present invention, the first housing and the second housing are two single parts with identical structures, and the first housing and the second housing are axially assembled and aligned by rotating 180° relative to each other.

[0012] In a preferred embodiment of the present invention, the mounting groove is connected to the mounting cavity.

[0013] The beneficial effects of this invention are as follows: Through a 180-degree rotationally symmetrical split structure, the first and second housings are essentially identical universal single-unit parts, requiring only one part drawing and one set of processing programs for mass production. Since the first and second housings are completely interchangeable and have no distinction between upper and lower models, no matching is needed during assembly, significantly improving assembly tolerance and reducing production costs. Simultaneously, the assembled mounting cavity is completely symmetrical in terms of cavity shape, gradient transition, and mounting reference, resulting in better consistency of the cell's electromagnetic boundaries and easier simulation matching. Furthermore, this invention completely eliminates the welding process. The internal core plate and the first and second connecting parts at both ends are all connected using purely mechanical fastening. High-precision hole-post positioning and fitting ensure seamless alignment of the internal curved surface of the mounting cavity with the transmission channel, completely eliminating uneven weld points, weld beads, and high-temperature deformation caused by welding from the source, resulting in a continuous and smooth inner cavity surface. This design effectively avoids electromagnetic field distortion, impedance shift, and standing wave degradation under high-frequency operating conditions, enabling the cell to possess excellent impedance matching and low-loss transmission characteristics over an ultra-wide bandwidth. Finally, the entire invention is secured by the first fastener, the second fastener, and the third fastener. Combined with the cover plate locked in the mounting slot by the first fastener, the structure can be repeatedly disassembled and calibrated without damaging the cavity, and subsequent debugging and replacement of spare parts are extremely convenient and universal. Attached Figure Description

[0014] Figure 1 This is one of the structural schematic diagrams of the present invention; Figure 2 This is the second structural schematic diagram of the present invention; Figure 3 The diagram shows the electromagnetic simulation results of this invention. Figure 4 The figure shows the measured results of this invention; In the figure: 11, first connector; 12, second connector; 21, first housing; 22, second housing; 3, cover plate; 4, first fastener; 41, first mounting hole; 5, core plate; 6, second fastener; 61, second mounting hole; 7, third fastener; 71, third mounting hole; 8, mounting cavity; 9, mounting groove. Detailed Implementation

[0015] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0016] Example like Figures 1 to 4 As shown, this embodiment provides a broadband TEM chamber for EMC testing of integrated circuits. The main body includes a first housing 21 and a second housing 22 disposed opposite to each other, wherein a mounting cavity 8 is formed between the first housing 21 and the second housing 22; the mounting cavity is used to mount the core board 5. The main body of the TEM chamber is assembled by docking the first housing 21 and the second housing 22 in a 180° rotationally symmetrical manner. When these two housing parts with precise concave structures are fastened together face to face, their respective internal spaces are perfectly aligned and closed geometrically, thus jointly constructing an independent closed mounting cavity 8 within the main body. This mounting cavity 8 directly serves as the electromagnetic waveguide and shielding chamber for the entire chamber. In the assembled and operating state, the core electromagnetic transmission component, the core plate 5, is transversely and stably suspended and fixed on the central reference plane of the mounting cavity 8, maintaining a micron-level precise and uniform spatial interlayer between the core plate 5 and the surrounding inner walls of the first housing 21 and the second housing 22. This creates a transverse electromagnetic wave channel with stable transmission characteristics within the mounting cavity 8, providing a standard electromagnetic field testing environment for transmitting high-frequency signals to the integrated circuit under test.

[0017] After the first housing 21 and the second housing 22 are positioned opposite each other, the first connector 11 and the second connector 12 are respectively installed at both ends of the main body. In specific implementation, after the first housing 21 and the second housing 22 are assembled and aligned, the main body will expose physical docking surfaces for high-frequency signal input and output at both ends of its axial direction. At this time, the first connector 11 and the second connector 12 are respectively aligned with these two axial end surfaces of the main body and fitted together, so that the internal center conductors of the two connectors can pass through the inner mounting cavity 8 from the outside and achieve high-precision coaxial docking with the two ends of the core plate 5 previously fixed in the center of the cavity. During operation and testing, the first connector 11 is responsible for introducing the high-frequency excitation signal generated by the external test instrument into the cavity without loss. After the signal is transmitted through the core plate 5 and converted into a transverse electromagnetic wave, it is then output by the second connector 12 located at the other end of the first housing 21 and the second housing 22 and fed back to the receiving device, thereby constructing a completely symmetrical, low-loss and impedance-continuous high-frequency signal transmission link at both ends of the main body.

[0018] The mounting cavity 8, formed by the lateral assembly of the first housing 21 and the second housing 22, has waveguide gradient surfaces on its inner sidewalls that are compatible with the core plate 5. When the first housing 21 and the second housing 22 are laterally assembled, their inner walls will perfectly align on both axial sides of the mounting cavity 8 and combine to form a specific waveguide geometric gradient structure. As the width of the core plate 5 gradually narrows linearly as it extends towards both ends, the waveguide gradient surfaces on the inner walls of the mounting cavity 8 are precisely adapted to this gradient trend in three-dimensional geometry, ensuring that the relative ratio between the cross-sectional area of ​​the core plate 5 and the cross-sectional area of ​​the mounting cavity 8 remains constant at any cross-section extending outward from within the mounting cavity 8. When transmitting high-frequency signals, this precisely fitted waveguide gradient surface ensures that the distributed capacitance and distributed inductance of the transmission interface remain in dynamic equilibrium as the signal passes through the gradient transition regions on both sides of the chamber's axis. This provides a continuous, non-abrupt 50-ohm characteristic impedance across an ultra-wide frequency band from DC to 10 GHz, reducing signal reflection from a physical structural perspective. The inner wall and core plate are recessed according to a linear gradient structure to ensure that the electromagnetic waveguide cross-section remains in a constant resistance state.

[0019] Both the first housing 21 and the second housing 22 have mounting grooves 9 on one side; the mounting grooves 9 are used to place the cover plate 3, wherein the cover plate 3 has through holes for mating with the first fastener 4. Aligned recessed stepped mounting grooves 9 are formed on the same machined surface of both the first housing 21 and the second housing 22. When the first housing 21 and the second housing 22 are laterally assembled and aligned, these two mounting grooves 9 are combined on the top surface of the body to form a complete square test opening for connecting the internal cavity. In the test operation state, the cover plate 3, used to support the integrated circuit under test or to shield external interference, is precisely placed and embedded in the mounting groove 9, so that its outer periphery achieves stable geometric positioning and fit with the stepped surface of the mounting groove 9. At this time, the operator aligns the first fastener 4 with the preset through hole on the cover plate 3 and passes it through. After the threaded part of the first fastener 4 passes through the cover plate 3, it directly engages with the corresponding threaded hole on the bottom surface of the mounting groove 9, thereby firmly pressing and locking the cover plate 3 in the mounting groove 9 of the first housing 21 and the second housing 22. While ensuring the continuity of the electromagnetic shielding of the cavity during testing, the reliable fixing and quick disassembly maintenance of the cover plate 3 are achieved.

[0020] The first connector 11 and the second connector 12, located at both ends of the main body, are connected to the main body via third fasteners 7. When the first connector 11 and the second connector 12 are axially fitted to both ends of the main body, the operator aligns and passes multiple third fasteners 7 through the flange mounting holes on the outer periphery of the first connector 11 and the second connector 12. Subsequently, the threaded portion of the third fastener 7 is directly screwed into the corresponding threaded hole formed by the lateral splicing of the first housing 21 and the second housing 22 and their alignment on the axial end face, and axial tightening force is gradually applied through thread engagement. In the operating and assembled state, the third fasteners 7 firmly press the first connector 11 and the second connector 12 towards the center of the main body, so that the mechanical mounting end face of the connector and the mating end face of the two housings achieve a micron-level tight fit, thereby ensuring the rigidity and stability of the mechanical insertion fit between the internal center conductor and the internal core plate 5 of the connector, and constructing a high-reliability, deformation-free, and low-loss high-frequency signal input and output path in a purely mechanical locking state.

[0021] The first housing 21 and the second housing 22 have mounting grooves 9 with bosses, and the bosses have first mounting holes 41. In a local area of ​​the mounting grooves 9 of the first housing 21 and the second housing 22, a specific geometric boss is precisely machined upwards, protruding above the bottom surface of the mounting groove, to serve as a vertical support reference and positioning reliance for the cover plate 3. When the first housing 21 and the second housing 22 are assembled and connected, the bosses on the two housings are aligned with each other and form a stable mounting stepped surface. The surface of the boss is pre-cut with a first mounting hole 41 extending vertically downwards. During assembly and testing, the cover plate 3 is fastened into the mounting groove 9 and flatly overlaps the top surface of the boss. The through hole on the outer periphery of the cover plate 3 and the first mounting hole 41 on the boss are precisely coaxially aligned. At this time, the hand screw, which is the first fastener 4, passes through the through hole of the cover plate 3 and is directly screwed into the threaded structure inside the first mounting hole 41. This securely locks the cover plate 3 onto the boss in a rigid, suspended or precisely limited manner. The height and limiting design of the boss not only ensures the uniform transmission of the fastening force, but also ensures from a physical structure perspective that the cover plate 3 will not undergo local deformation or wear on the edge electromagnetic boundary of the internal mounting cavity 8 when it is frequently and quickly disassembled.

[0022] The first housing 21 and the second housing 22 are each provided with a plurality of second mounting holes 61 on opposite sides. The first housing 21 and the second housing 22 are connected by second fasteners 6 passing through the second mounting holes 61. Specifically, the wavelength of electromagnetic waves at the 10GHz frequency is 3cm. For the rectangular aperture cutoff wavelength λ=2a, amin=1.5cm. Since the horizontal splice seam is filled with screws, the maximum rectangular gap that can be formed is 1.2cm*0.01cm. Therefore, the leakage of the formed gap will be significantly attenuated at 10GHz. In this embodiment, the highest frequency is 8G, corresponding to a wavelength of 3.75cm. The maximum allowable gap length is 1.875cm. The leakage is significantly attenuated at 1.2cm. In another preferred embodiment of the present invention, in order to achieve better shielding, the number of screws can be increased to reduce the length of the rectangular gap. In addition, interlocking steps and annular conductive pads can also achieve better shielding performance.

[0023] The end plates of the first connector 11 and the second connector 12 are each provided with a third mounting hole 71, which is used to install the first connector 11 and the second connector 12 with the first housing 21 or the second housing 22.

[0024] The first housing 21 and the second housing 22 are two identical single parts, and they are axially aligned and connected by rotating 180° relative to each other. The mounting groove 9 is connected to the mounting cavity 8. The first housing 21 and the second housing 22 are manufactured as identical single parts in structure, shape, and dimensions. During assembly, operators do not need to distinguish between upper and lower models; they only need to rotate one housing 180° horizontally or axially relative to the other. The mating reference surfaces and internal mechanical holes of both will align, allowing for direct assembly and mechanical locking, significantly reducing the process costs of CNC drawing preparation and mass production. In this aligned connection state, the mounting slots 9 on the two shell surfaces and the closed internal mounting cavity 8 are physically connected, thus forming a test channel that can be directly probed downwards from the outside. During test operation, external test probes or control communication cables of the integrated circuit under test can pass through the cover plate 3 and directly enter the mounting cavity 8 through the interconnected mounting slots 9. While ensuring the integrity of the high-frequency electromagnetic shielding boundary of the small chamber, it provides a convenient and fast test and signal interaction path for the chips on the internal core board 5.

[0025] Specifically, two identical single-unit parts, namely the first housing 21 and the second housing 22, are axially assembled and aligned by rotating 180° relative to each other, forming a closed mounting cavity 8 between them. The core plate 5 is transversely and stably suspended and fixed on the center surface inside the mounting cavity 8. The two ends of the main body are axially fastened with the first connector 11 and the second connector 12, respectively. The mounting cavity 8 formed by the transverse assembly of the first housing 21 and the second housing 22 has a waveguide gradient curved surface on its inner sidewall that is compatible with the core plate 5, thereby improving the consistency of the internal electromagnetic boundary during test operation, maintaining excellent impedance matching characteristics and reducing transmission loss in the DC to 10GHz full frequency band. At the same time, one side of the first housing 21 and the second housing 22 is provided with a mounting groove 9 that communicates with the mounting cavity 8. The mounting groove 9 has a boss with a first mounting hole 41. The cover plate 3 is locked onto the mounting groove 9 by the first fastener 4 and the through hole to form a complete shielded cavity and provide a test channel. The beneficial effects of this invention are as follows: First, the first housing 21 and the second housing 22 are the same type of universal structural components. During mass production, only one part drawing and one set of machining programs are needed. There is no misassembly or matching required during assembly, significantly reducing the difficulty of CNC machining, drawing preparation, and production costs. Second, the core plate 5 inside the entire chamber is positioned with the first connecting member 11 and the second connecting member 12 through precision post holes and is mechanically locked together using the second fastener 6 and the third fastener 7. This completely eliminates the welding process, thoroughly preventing uneven weld points and weld defects caused by welding from a process perspective. The design eliminates issues such as lumps and high-temperature deformation, ensuring a continuous and smooth inner cavity surface. This effectively avoids defects such as field distortion, impedance shift, and increased insertion loss caused by discontinuous impedance at the transmission interface under high-frequency operating conditions. Within the measured range of 9kHz-8.5GHz, the voltage standing wave ratio (VSWR) at both ports is less than 1.2, and the insertion loss is less than 1dB, ensuring stable and controllable high-frequency electromagnetic performance. Furthermore, the purely mechanical locking structure and the hand-tightening screw fastening method of the cover plate 3 allow for repeated disassembly, calibration, and replacement of spare parts without damaging the cavity structure. Subsequent debugging and maintenance are extremely versatile and convenient.

[0026] like Figure 3 As shown, the TEM cell in this embodiment exhibits excellent symmetry, with identical simulation parameters at both ports, and the VSWR and insertion loss curves completely overlapping. The figure above shows the electromagnetic simulation results of this TEM cell. The simulation curves indicate that within the DC to 10 GHz frequency band, the cell's voltage VSWR < 1.2, and the insertion loss |S21| < 1 dB. The simulation results demonstrate that this TEM cell possesses excellent broadband impedance matching characteristics, low high-frequency transmission loss, and stable electromagnetic transmission performance, meeting the high-precision testing requirements for radiated emissions and radiated immunity of integrated circuits.

[0027] Figure 4The test results show that, within the range of 9kHz-8.5GHz, the VSWR of the two ports is <1.2, which is consistent with the simulated VSWR curve and the trend of change is basically the same. The transmission coefficients S21 and S12 of the two ports are both greater than -1, meaning that the insertion losses |S21| and |S12| are both less than 1, which is close to the simulation results and the trend of change is basically the same. The actual test results verify that the TEM cell has excellent impedance matching and low-loss transmission characteristics, and the structural design and manufacturing process meet the high-frequency performance requirements.

[0028] Specifically, such as Figure 3 and Figure 4 As shown, to ensure a clear understanding for those skilled in the art, the English abbreviations and corresponding curves in the figures are explained in detail below. The prefix "Sim" in the figures represents electromagnetic simulation results, "Mea" represents actual test results, and "TEM8G" represents the broadband TEM cell with a maximum test frequency of 8 GHz in this embodiment of the invention.

[0029] Figure 3 This is a graph showing the electromagnetic simulation results of the present invention. The graph contains two curves: the curve labeled "Sim-S21_TEM8G" represents the simulated transmission coefficient (i.e., insertion loss S21) of the cell, and its value is referenced to the right vertical axis; the curve labeled "Sim_VSWR_TEM8G" represents the simulated voltage standing wave ratio (VSWR) of the cell, and its value is referenced to the left vertical axis. Figure 3 The simulation curves show that, in the full frequency band from DC to 10 GHz, the voltage standing wave ratio (VSWR) of the small cell is <1.2 and the insertion loss |S21| is <1 dB.

[0030] Figure 4 This is a comparison chart of the measured and simulated results of this invention. The upper region of the chart shows the transmission coefficient comparison curves (refer to the right vertical axis), where "Mea-TEM8G-S12" represents the measured reverse transmission coefficient, "Mea-TEM8G-S21" represents the measured forward transmission coefficient, and "Sim-S21_TEM8G" represents the corresponding simulated transmission coefficient. The lower region of the chart shows the voltage standing wave ratio (VSWR) comparison curves (refer to the left vertical axis), where "Sim_VSWR_TEM8G" represents the reference simulated VSWR, "Mea-TEM8G-VSWR1" represents the measured port 1 VSWR, and "Mea-TEM8G-VSWR2" represents the measured port 2 VSWR. It can be seen that, within the range of 9kHz-8.5GHz, the measured VSWR curves of both ports are at the same level as the simulated curves and the trend of change is basically consistent; the measured transmission coefficient curves of both ports are both greater than -1 (i.e. the insertion loss is less than 1dB), and the measured results fully verify that the TEM cell has excellent impedance matching and low-loss transmission characteristics.

[0031] This invention utilizes a 180-degree rotationally symmetrical split structure, making the first and second housings identical, universal single-unit parts. For mass production, only one part drawing and one set of machining programs are needed. Since the first and second housings are completely interchangeable and have no distinction between upper and lower models, there is no misassembly or matching required during assembly, significantly improving assembly tolerance and reducing production costs. Simultaneously, the assembled mounting cavity is completely symmetrical in terms of cavity shape, gradient transition, and mounting reference, resulting in better consistency of the cell's electromagnetic boundaries and easier simulation matching. Furthermore, this invention completely eliminates the welding process. The internal core plate and the first and second connecting parts at both ends are all connected using purely mechanical fastening. High-precision hole-post positioning and fitting ensure seamless alignment of the internal curved surface of the mounting cavity with the transmission channel, completely eliminating uneven weld points, weld beads, and high-temperature deformation caused by welding from the source, resulting in a continuous and smooth inner cavity surface. This design effectively avoids electromagnetic field distortion, impedance shift, and standing wave degradation under high-frequency operating conditions, enabling the cell to possess excellent impedance matching and low-loss transmission characteristics over an ultra-wide bandwidth. Finally, the entire invention is secured by the first fastener, the second fastener, and the third fastener. Combined with the cover plate locked in the mounting slot by the first fastener, the structure can be repeatedly disassembled and calibrated without damaging the cavity, and subsequent debugging and replacement of spare parts are extremely convenient and universal.

[0032] In existing technologies, to ensure the high-frequency enclosure and electrical connection of transverse electromagnetic wave chambers, those skilled in the art typically employ a top-bottom irregularly shaped split structure and a heating welding process. This results in a long-standing and irreconcilable technical contradiction between the complexity of mechanical processing and the continuity of high-frequency radio frequency impedance. This invention breaks through conventional design thinking, creatively disassembling the cavity into two identical structurally identical, universal single-unit parts that can be assembled by rotating them 180° relative to each other. The entire process utilizes purely mechanical fastening to replace traditional welding processes. This design is not a simple mechanical replacement or obvious assembly, but rather utilizes the axial symmetry of spatial geometry to directly improve the uniformity and consistency of the internal electromagnetic boundaries. Simultaneously, it avoids damage to the high-frequency conductive interface from thermal deformation and residual weld beads from the process source, achieving an effective synergy between simplified CNC machining and optimized ultra-wideband radio frequency performance. This has outstanding substantial characteristics in the field of integrated circuit EMC testing equipment.

[0033] In wideband high-frequency signal transmission (e.g., DC to 10 GHz), any minute physical step or interface discontinuity in the transmission path can cause significant signal reflection and standing wave distortion. This invention cleverly uses a waveguide gradient surface formed by the transverse splicing of the first and second shells to achieve a three-dimensional geometric fit with the linear gradient trend of the core plate. This ensures that the relative ratio of the core plate's cross-sectional area to the cavity's cross-sectional area remains constant throughout the gradient transition zone at both ends. This precise coordination of the mechanical profile, without relying on welded conduction, maintains a dynamic balance between the distributed capacitance and distributed inductance of the transmission interface, ensuring the continuity of the 50-ohm characteristic impedance across the entire frequency band of the chamber, and reliably keeping the electromagnetic waveguide cross-section in a constant resistance state. Simulation and experimental results confirm that this scheme achieves excellent characteristics of a voltage standing wave ratio (VSWR) of less than 1.2 and an insertion loss of less than 1 dB within a wide frequency range of 9 kHz to 8.5 GHz, representing a significant improvement in high-frequency VSWR and bandwidth compared to traditional welded chambers.

[0034] Furthermore, conventional split-type shielding cavities often rely on irreversible welding or complex sealing measures to suppress high-frequency electromagnetic leakage. This invention, however, utilizes the cutoff principle of electromagnetic waveguides, achieving effective suppression of high-frequency gap radiation through a rational layout of purely mechanical fasteners. By controlling the interlocking locking positions between the second fasteners, the length of the rectangular gap formed at the transverse splice is limited to below the cutoff wavelength of the corresponding high-frequency threshold rectangular aperture (e.g., for 10GHz applications, the maximum gap length is controlled at 1.2cm, significantly smaller than the corresponding cross-sectional area cutoff size of 1.5cm), resulting in significant attenuation of high-frequency electromagnetic wave leakage at the gap. This technical solution, without introducing a non-removable welded structure, effectively balances the electromagnetic compatibility shielding requirements of ultra-wideband high-precision testing with the engineering maintenance needs of repeated non-destructive disassembly, recalibration, and spare parts replacement, achieving technical effects that are difficult to achieve with existing conventional structures.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A broadband TEM chamber for EMC testing of integrated circuits, characterized in that, The main body includes a first housing (21) and a second housing (22) disposed opposite to each other, wherein, An installation cavity (8) is formed between the first housing (21) and the second housing (22); The mounting cavity is used to mount the core board (5); After the first housing (21) and the second housing (22) are positioned opposite each other, the first connector (11) and the second connector (12) are respectively installed at both ends of the main body. The mounting cavity (8) formed by the horizontal splicing of the first housing (21) and the second housing (22) has a waveguide gradient surface on its inner sidewall that is compatible with the core plate (5).

2. The broadband TEM chamber for EMC testing of integrated circuits according to claim 1, characterized in that, Both the first housing (21) and the second housing (22) have a mounting groove (9) on one side; The mounting slot (9) is used to place the cover plate (3), wherein, The cover plate (3) is provided with a through hole for cooperating with the first fastener (4).

3. A broadband TEM chamber for EMC testing of integrated circuits according to claim 1, characterized in that, The first connector (11) and the second connector (12) located at both ends of the main body are connected to the main body via a third fastener (7).

4. A broadband TEM chamber for EMC testing of integrated circuits according to claim 2, characterized in that, The mounting groove (9) of the first housing (21) and the second housing (22) has a boss, on which a first mounting hole (41) is provided.

5. A broadband TEM chamber for EMC testing of integrated circuits according to claim 1, characterized in that, Both the first housing (21) and the second housing (22) have a plurality of second mounting holes (61) on opposite sides. The first housing (21) and the second housing (22) are connected by a second fastener (6) passing through the second mounting hole (61).

6. A broadband TEM chamber for EMC testing of integrated circuits according to claim 1, characterized in that, The end plates of the first connector (11) and the second connector (12) are provided with a third mounting hole (71) for mounting the first connector (11) and the second connector (12) to the first housing (21) or the second housing (22).

7. A broadband TEM chamber for EMC testing of integrated circuits according to claim 1, characterized in that, The first housing (21) and the second housing (22) are two single parts with the same structure, and the first housing (21) and the second housing (22) are axially assembled and aligned by rotating 180° relative to each other.

8. A broadband TEM chamber for EMC testing of integrated circuits according to claim 2, characterized in that, The mounting groove (9) is connected to the mounting cavity (8).

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