A metal probe type high-power coplanar magic T

Abstract

This invention discloses a metal probe-type high-power coplanar magic T, belonging to the field of microwave and millimeter-wave technology. It includes a main shielding box and a load shielding box. The main shielding box has one combining port, two distribution ports, and a cylindrical cavity. Inside the main shielding box are a waveguide E-T junction, a metal probe, a PTFE sleeve, a half-height waveguide-standard waveguide gradient structure, and an L-shaped waveguide. The load shielding box includes a base and a cover plate. The base has an open cavity structure, and heat sinks are distributed on the outer wall of the base. Inside the base are a microwave printed circuit board, a tungsten-copper carrier, and a diamond-based power resistor. This invention moves the vertical isolation end of the waveguide magic T to the horizontal direction by introducing a metal probe, resulting in a compact structure that facilitates the miniaturization of the power amplifier. This invention features good amplitude and phase consistency, low insertion loss, good port VSWR, high isolation, and the ability to withstand high power.

Description

Technical Field

[0001] This invention belongs to the field of microwave and millimeter wave technology, and in particular, it is a metal probe type high-power coplanar magic T, which is suitable for solid-state power amplifiers in satellite communication ground stations. Background Technology

[0002] The waveguide magic T is a commonly used power divider / combiner. Its disadvantage is that the four waveguide arms are located in different planes, which makes module assembly inconvenient. In addition, at high frequencies, the matching elements of the waveguide magic T (such as cones, pins, diaphragms, etc.) become smaller, making them very difficult to manufacture.

[0003] To address the above issues, existing technologies have made the following contributions to coplanar magic T structures:

[0004] The patent with publication number CN103378395A proposes an E-plane waveguide magic T with coplanar arms, which is the first time that an E-plane waveguide magic T with coplanar arms has been disclosed.

[0005] In August 2013, Wang Pengfei et al. published "Design of a Novel E-plane Integrated Waveguide Magic T" in Radio Engineering, proposing a Ka-band coplanar magic T, which mainly consists of a waveguide ET junction, a microstrip probe and thin-film circuits.

[0006] In November 2013, Wu Qiongsen et al. published "An E-plane waveguide magic T with coplanar arms" at the National Antenna Conference, whose structure is consistent with the patent published with CN103378395A.

[0007] The patent with announcement number CN216413229U proposes a 100-watt ultra-compact high-isolation Ku-band coplanar magic T, which features low insertion loss, small size, and the ability to assemble a power amplifier module by simply building a micro-assembly chip.

[0008] The patent with publication number CN121238209A proposes a K-band full-bandwidth high-power magic-T synthesizer, which consists of a waveguide ET junction, a microstrip probe, and a diamond load.

[0009] The coplanar magic T provided in the above papers and patents has the following drawbacks: they all use a suspended microstrip probe structure, the microstrip thickness on microwave printed circuit boards is generally 17μm or 35μm, and the microstrip thickness on ceramic thin film circuit boards is generally 4μm, neither of which can withstand high power; when the power is high, the suspended microstrip probe will be burned out, affecting the long-term reliability of the equipment. Summary of the Invention

[0010] To overcome the shortcomings of the prior art, this invention proposes a metal probe-type high-power coplanar magic T, which features good amplitude and phase consistency, low insertion loss, good port VSWR, high isolation, and the ability to withstand high power.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] A high-power coplanar magic T-type metal probe includes a main shielding box and a load shielding box. Both the main shielding box and the load shielding box have cavities inside. The main shielding box has a combining port on the combining side and two distributing ports on the distributing side. A straight waveguide extending into the main shielding box is provided at the combining port. A waveguide ET junction is provided at the end of the straight waveguide. A half-height waveguide-standard waveguide gradient structure is provided at each of the two branches of the waveguide ET junction. The end of the half-height waveguide-standard waveguide gradient structure is connected to an L-shaped waveguide. The end of the L-shaped waveguide extends to the corresponding distributing port. A boss is provided at the bottom of the waveguide ET junction, facing the straight waveguide. A cylindrical cavity is also provided on the distributing side of the main shielding box between the two distributing ports. The cylindrical cavity extends to the boss and communicates with the cavity of the waveguide ET junction. The straight waveguide, the waveguide ET junction, the half-height waveguide-standard waveguide gradient structure, the L-shaped waveguide, and the cylindrical cavity together constitute the cavity of the main shielding box. The cavity of the main shielding box has a bilaterally symmetrical structure.

[0013] The load shielding box is set at the opening of the cylindrical cavity. A metal probe is set inside the cylindrical cavity. The head of the metal probe extends from the boss and penetrates into the interior of the waveguide ET junction.

[0014] The cavity of the load shielding box is an open cavity with a tungsten copper carrier at the end of the cavity. A diamond-based power resistor is placed on the tungsten copper carrier. A microwave printed circuit board is also placed inside the cavity. The microwave printed circuit board has a microstrip line. The front end of the microstrip line is connected to the end of the metal probe, and the rear end of the microstrip line is connected to the input terminal of the diamond-based power resistor. The grounded bottom surface of the diamond-based power resistor is connected to the tungsten copper carrier.

[0015] Furthermore, the main shielding box includes a lower box body and an upper box body. The cavity of the main shielding box is located in the lower box body. The upper box body is provided with multiple countersunk holes, and the lower box body is provided with corresponding threaded holes. The upper box body and the lower box body are fixed by screws passing through the countersunk holes and threaded holes.

[0016] The load shielding box includes a base and a cover plate. The cavity of the load shielding box is located in the base. The cover plate has multiple countersunk holes, and the base has corresponding threaded holes. The base and the cover plate are fixed by screws passing through the countersunk holes and threaded holes. Heat sinks are distributed on the side wall of the base.

[0017] Furthermore, the metal probe is divided into three sections: head, middle, and tail. The middle section serves as an impedance matching section, with the head diameter > tail diameter > middle diameter. The cylindrical cavity is divided into two sections, with the front section diameter < the rear section diameter. The tail of the metal probe is fixed in the rear section of the cylindrical cavity by a polytetrafluoroethylene (PTFE) sleeve. The interface between the front and rear sections forms a barrier that prevents the PTFE sleeve from entering the waveguide ET junction. The tail of the metal probe serves as an inner conductor and together with the PTFE sleeve and the cylindrical cavity, forms a coaxial transmission line structure.

[0018] Furthermore, the combining port of the waveguide ET junction is a standard waveguide, and the two split ports are half-height waveguides.

[0019] Furthermore, the L-shaped waveguide consists of two standard straight waveguide segments that intersect perpendicularly, with the corner at the intersection cut at a 45° angle.

[0020] Furthermore, the half-height waveguide-standard waveguide transition structure is square horn-shaped, realizing the structural transformation from half-height waveguide to standard waveguide.

[0021] Furthermore, the microwave printed circuit board is bonded to the cavity with conductive adhesive, the diamond-based power resistor is the power resistor load, the diamond-based power resistor is placed on the tungsten copper carrier by gold-tin eutectic bonding process, the tungsten copper carrier is fixed in the groove at the end of the cavity by tin-lead bonding process, and the rear end of the microstrip line is connected to the input end of the diamond-based power resistor by multiple bonding alloy strips.

[0022] Furthermore, the substrate of the microwave printed circuit board is an RT / duroid 5880 microwave dielectric board.

[0023] Furthermore, the main shielding box is made of 6063-T6 aluminum alloy with gold plating; the load shielding box is made of oxygen-free copper with gold plating.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. The metal probe-type high-power coplanar magic T proposed in this invention has the characteristics of good amplitude and phase consistency, low insertion loss, good port standing wave ratio, high isolation, and high power tolerance. It solves the problem that the suspended microstrip probe in the existing coplanar magic T structure is easily burned out, resulting in low equipment reliability.

[0026] 2. This invention has the advantage of being able to withstand high power. While ensuring good heat dissipation of the load shielding box, a diamond-based power resistor capable of withstanding 50W continuous wave power can achieve 200W of high-power synthesis; a diamond-based power resistor capable of withstanding 100W of continuous wave power can achieve 400W of high-power synthesis.

[0027] 3. The present invention has a compact structure, which is conducive to the miniaturization of power amplifiers and solves the problem that the traditional waveguide magic T isolation port needs to be connected to a high-power waveguide load, resulting in an excessively large power combining structure. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the external structure of the present invention. The combining port of the main shielding box is port I. Figure 1 The two distribution ports shown are port II and port III from left to right, and ports II and III are symmetrically distributed along the center line of the main shielding box.

[0029] Figure 2 This is a structural diagram of the lower box and the base;

[0030] Figure 3 This is an exploded view of the structure of the present invention;

[0031] Figure 4 This is a top view of the lower box and base;

[0032] Figure 5 This is a top view of the base;

[0033] Figure 6 This is the rear view of the lower box.

[0034] Figure 7 This is a schematic diagram of a metal probe and a polytetrafluoroethylene sleeve;

[0035] Figure 8 A screenshot of the dynamic electric field distribution of the present invention when the input signal is at port I;

[0036] Figure 9 This is a graph showing the amplitude curves of output port II and port III of this invention;

[0037] Figure 10 This is a phase curve diagram of output port II and port III of the present invention;

[0038] Figure 11 This is a graph showing the isolation between output port II and port III of this invention.

[0039] Figure 12 This is a return loss curve diagram of port I, port II and port III of the present invention. Detailed Implementation

[0040] To facilitate understanding of the technical content of this invention by those skilled in the art, the following description, in conjunction with the accompanying drawings, further illustrates the invention.

[0041] A high-power coplanar magic T-junction with a metal probe includes a main shielding box and a load shielding box. The main shielding box consists of a lower box and an upper box, with an internal cavity. One end of the main shielding box has a combining port, and the other end has two distributing ports. A cylindrical cavity is located on the side wall between the two distributing ports. The main shielding box contains a waveguide ET junction, a metal probe, a PTFE sleeve, a half-height waveguide-standard waveguide gradient structure, and an L-shaped waveguide. The load shielding box consists of a base and a cover. The base has an open cavity structure, and heat sinks are distributed on the side wall at the end of the cavity. The cavity contains a microwave printed circuit board, a tungsten copper carrier, and a diamond-based power resistor.

[0042] The metal probe-type high-power coplanar magic T has a left-right symmetrical structure; the combining port of the main shielding box is connected to the combining port of the waveguide ET junction; the two shunt ports of the waveguide ET junction are connected to the two distribution ports of the main shielding box through a half-height waveguide-standard waveguide gradient structure and an L-shaped waveguide, respectively; a boss is provided inside the waveguide ET junction; the head of the metal probe extends from the boss and penetrates into the interior of the waveguide ET junction, and the tail of the metal probe is fixed in the cylindrical cavity of the main shielding box by a polytetrafluoroethylene sleeve; the very end of the metal probe is soldered to the microstrip at the front end of the microwave printed circuit board inside the load shielding box.

[0043] When the metal probe-type high-power coplanar magic T is used as a splitter, the microwave signal is input from the combining port of the main shielding box, and the two distribution ports of the main shielding box output two equal-amplitude and in-phase signals of equal power. When used as a combiner, the two equal-amplitude and in-phase signals input from the distribution ports can be combined into one high-power signal.

[0044] The cylindrical cavity of the main shielding box consists of two coaxial cylindrical cavities. The first cylindrical cavity has a smaller diameter and shorter length, and its function is to prevent the polytetrafluoroethylene sleeve from entering the waveguide ET junction. The second cylindrical cavity has a larger diameter and longer length.

[0045] The metal probe has a three-section structure: the head cylinder has the thickest diameter; the middle cylinder has the thinnest diameter and serves as the impedance matching section; and the tail cylinder has a moderate diameter and serves as the inner conductor, forming a coaxial transmission line structure with the PTFE sleeve and the cylindrical cavity of the main shielding box.

[0046] The combining port of the waveguide ET junction is a standard waveguide, and the two sliding ports are half-height waveguides.

[0047] The L-shaped waveguide consists of two standard straight waveguide segments that intersect perpendicularly. The corner at the intersection is cut at 45° to ensure that it has the minimum insertion loss and the optimal return loss.

[0048] The half-height waveguide-to-standard waveguide transition structure is a square horn shape, realizing the structural transformation from a half-height waveguide to a standard waveguide, and has the characteristics of low insertion loss and excellent return loss.

[0049] The diamond-based power resistor is a power resistive load that can withstand 50W continuous wave power. The diamond-based power resistor is placed on a tungsten-copper carrier using a gold-tin eutectic bonding process. The tungsten-copper carrier is fixed in a groove in the load shielding box base using a tin-lead bonding process. The microstrip on the microwave printed circuit board near the groove is connected to the input terminal of the diamond-based power resistor through multiple bonded alloy strips.

[0050] The main shielding box consists of a lower box and an upper box that fit together. The upper box has multiple countersunk holes, and the lower box has corresponding threaded holes. The upper box and the lower box are fixed together by screws that pass through the countersunk holes and threaded holes. The lower box has a through hole on each of its left and right sides, which can be fixed to the heat sink or the amplifier chassis by screws.

[0051] The load shielding box consists of a base and a cover plate. The cover plate has multiple countersunk holes, and the base has corresponding threaded holes. The base and cover plate are secured together with screws passing through the countersunk holes and threaded holes. The microwave printed circuit board is bonded to the base with conductive adhesive. The base has two symmetrical mounting ears, each with a through hole, which can be screwed into a heat sink or amplifier chassis. Seven parallel thin heat sink fins are distributed on the outer wall of the base to ensure good heat dissipation.

[0052] This invention moves the vertical isolation terminal of the waveguide magic T to a horizontal direction by introducing a metal probe, resulting in a compact structure that facilitates the miniaturization of power amplifiers. This invention features good amplitude and phase consistency, low insertion loss, good port VSWR, high isolation, and the ability to withstand high power.

[0053] Here are more specific examples:

[0054] See Figures 1-7 Taking a Ku-band (13.75-14.5GHz) metal probe-type high-power coplanar magic T as a specific example, its structure includes a main shielding box 1 and a load shielding box 2. The main shielding box 1 is divided into a lower box 3 and an upper box 4, with an internal cavity. The main shielding box 1 has one combining port and two distribution ports, and a cylindrical cavity 101 is set at the middle position of the two distribution ports. The main shielding box 1 contains a waveguide ET junction 102, a metal probe 103, a polytetrafluoroethylene sleeve 104, a half-height waveguide-standard waveguide gradient structure 105, and an L-shaped waveguide 106. The load shielding box 2 is divided into a base 5 and a cover plate 6. The base 5 has an open cavity structure, and a heat sink structure is distributed on the outer wall of the base 5. The base 5 contains a microwave printed circuit board 501, a tungsten copper carrier 502, and a diamond-based power resistor 503.

[0055] The Ku-band metal probe-type high-power coplanar magic T has a symmetrical structure. The combining port of the main shielding box 1 is connected to the combining port of the waveguide ET junction 102. The two branch ports of the waveguide ET junction 102 are connected to the two distribution ports of the main shielding box 1 through the half-height waveguide-standard waveguide gradient structure 105 and the L-shaped waveguide 106, respectively. A boss 107 is provided inside the waveguide ET junction 102. The head of the metal probe 103 extends from the boss 107 and penetrates into the waveguide ET junction 102. The tail of the metal probe 103 is fixed in the cylindrical cavity 101 of the main shielding box 1 by a polytetrafluoroethylene sleeve 104. The very end of the metal probe 103 is welded to the microstrip at the front end of the microwave printed circuit board 501 inside the load shielding box 2.

[0056] The cylindrical cavity 101 of the main shielding box 1 consists of two coaxial cylindrical cavities. The first cylindrical cavity has a diameter of 3.6 mm and a length of 0.4 mm; the second cylindrical cavity has a diameter of 4.13 mm and a length of 5 mm. The PTFE sleeve 104 has an outer diameter of 4.1 mm and a length of 5 mm. These dimensions ensure that the PTFE sleeve 104 can be completely inserted into the second cylindrical cavity, while being blocked by the first cylindrical cavity, preventing the PTFE sleeve 104 from entering the waveguide ET junction 102.

[0057] The metal probe 103 has a three-section structure: the head cylinder has a diameter of 2mm and a length of 1.64mm; the middle cylinder has a diameter of 0.78mm and a length of 2.62mm, serving as an impedance matching section; and the tail cylinder has a diameter of 1.27mm and a length of 6mm, serving as an inner conductor. Together with the PTFE sleeve 104 and the cylindrical cavity 101 of the main shielding box 1, it forms a coaxial transmission line structure. This design references the structure of the SMA type RF coaxial connector in GB / T 11313.15-2018.

[0058] The characteristic impedance of an RF coaxial connector is calculated using the following formula:

[0059]

[0060] In the formula:

[0061] Z: Characteristic impedance, in Ω;

[0062] D: Inner diameter of the outer conductor, in mm;

[0063] d: Outer diameter of the inner conductor, in mm;

[0064] : The relative permittivity of the insulating medium.

[0065] According to GB / T 11313.15-2018, the SMA type connector operates at a frequency of 18GHz, with an outer conductor inner diameter of 4.13mm, an inner conductor outer diameter of 1.27mm, and a relative permittivity of PTFE dielectric of 2.02. Based on the above formula, the characteristic impedance of this coaxial connector can be calculated to be 49.7Ω.

[0066] The combining port of waveguide junction ET102 is a standard WR62 waveguide with a waveguide aperture size of 15.8mm × 7.9mm; the two split ports are half-height waveguides with a waveguide aperture size of 15.8mm × 3.95mm; the boss 107 has a width of 4.7mm and extends 2mm towards the combining port.

[0067] L-shaped waveguide 106 consists of two standard straight waveguides that intersect perpendicularly. The corner at the intersection is cut at 45°. The transverse and longitudinal incision dimensions are both 6.34 mm to ensure that it has the minimum insertion loss and the optimal return loss.

[0068] The half-height waveguide-standard waveguide transition structure 105 is square horn-shaped, realizing the structural transformation from a half-height waveguide (15.8mm×3.95mm) to a standard waveguide (15.8mm×7.9mm). According to the simulation of three-dimensional electromagnetic field software, the length of the half-height waveguide-standard waveguide transition structure 105 is 14mm, which has the characteristics of low insertion loss and excellent return loss.

[0069] The diamond-based power resistor 503 is a power resistor load suitable for the Ku band and can withstand 50W continuous wave power. The grounding bottom surface of the diamond-based power resistor 503 is placed on the tungsten copper carrier 502 through a gold-tin eutectic bonding process, with the bonding temperature set at 320-330℃. The tungsten copper carrier 502 is fixed in the groove of the load shielding box base 5 through a tin-lead bonding process, with the bonding temperature set at 210-230℃. The microstrip of the microwave printed circuit board 501 near the groove side and the input terminal of the diamond-based power resistor 503 are connected by multiple bonded alloy strips.

[0070] The diamond-based power resistor 503 can withstand 50W of continuous wave power, thus enabling 200W of high-power synthesis. If the diamond-based power resistor 503 is replaced with a power resistor load that can withstand 100W of continuous wave power, 400W of high-power synthesis can be achieved.

[0071] The microwave printed circuit board 501 is made of 0.508mm thick RT / duroid 5880 microwave dielectric board with a dielectric constant of 2.2, a copper layer thickness of 35μm, and a gold plating thickness of 1μm.

[0072] The main shielding box 1 consists of a lower box 3 and an upper box 4 that interlock. The upper box 3 has two through holes, and the lower box 4 has two blind holes. Two pins 108 are used to fix them through, ensuring that the upper box 3 and the lower box 4 are precisely aligned. The upper box 4 has multiple countersunk holes, and the lower box 3 has corresponding threaded holes. The lower box 3 and the upper box 4 are fixed by screws passing through the countersunk holes and threaded holes. The lower box 3 has a through hole on each of its left and right sides, which can be fixed to the heat sink or the power amplifier chassis by screws.

[0073] The load shielding box 2 consists of a base 5 and a cover plate 6. The cover plate 6 has multiple countersunk holes, and the base 5 has corresponding threaded holes. The base 5 and the cover plate 6 are fixed together by screws passing through the countersunk holes and threaded holes. The microwave printed circuit board 501 is bonded to the base with conductive adhesive at a bonding temperature of 150°C.

[0074] The load shielding box 2 has an open cavity structure and is installed flush against the outer wall of the cylindrical cavity 101 of the main shielding box 1. The base 5 has two symmetrical mounting ears, each with a through hole, which can be screwed into a heat sink or amplifier chassis. Seven parallel thin heat sink fins are distributed on the outer wall of the base 5. Each heat sink fin is 21.35mm × 5mm × 1mm in size, with a fin spacing of 1mm to ensure good heat dissipation.

[0075] The main shielding box 1 is made of 6063-T6 aluminum alloy with a thermal conductivity of 201W / (m•K) and is gold-plated. The load shielding box 2 is made of oxygen-free copper with a thermal conductivity of 400W / (m•K) and is gold-plated.

[0076] For this Ku-band metal probe-type high-power coplanar magic transducer (MT), dynamic electric field simulation can be performed using the three-dimensional electromagnetic field software HFSS. (See also...) Figure 8 When a 1W power signal is input to port I, the maximum field strength on the metal probe surface is less than 8.9kV / m; under standard atmospheric pressure, the breakdown field strength of dry air is 3MV / m, and the connector industry generally takes an empirical value of 984kV / m; therefore, the power capacity of the Ku-band metal probe type high-power coplanar magic T can be obtained as not less than 12kW.

[0077] Figures 9-11 These are the output port amplitude curve, phase curve, and isolation curve of the aforementioned Ku-band metal probe-type high-power coplanar magic T. Figure 12This is a graph showing the return loss curves for the input and output ports. As can be seen from the graph, within the frequency range of 13.75-14.5 GHz, the insertion loss of both output ports is within 0.03 dB; the amplitude difference between port II and port III is within 0.01 dB; the phase difference between port II and port III is within 0.2°; the isolation between port II and port III is better than 28 dB; and the return loss of both input and output ports is better than 27 dB.

[0078] As can be seen, the present invention has the characteristics of good amplitude and phase consistency, low insertion loss, good port standing wave ratio, high isolation, and high power tolerance. It solves the problem that the suspended microstrip probe in the existing coplanar magic T structure is easily burned out, resulting in low equipment reliability.

[0079] The basic working principle of this invention is as follows:

[0080] When used as a splitter, a signal with power P is input from the combining port I of the main shielding box 1. After passing through the waveguide ET junction 102 and the metal probe 103, it is split into two signals of equal amplitude and opposite phase. The two signals then pass through the half-height waveguide-standard waveguide tapered structure 105 and the L-shaped waveguide 106, respectively, and are output from ports II and III of the main shielding box 1 as two signals of equal amplitude and in phase, i.e., the power of each signal is P / 2. Conversely, when used as a combiner, the two signals of equal amplitude and in phase input from ports II and III can be combined into a single high-power signal, which is output from the combining port I.

[0081] The essence of the metal probe-type high-power coplanar magic T is to move the vertical isolation end of the waveguide magic T to the horizontal direction by introducing a metal probe; the metal probe couples the unbalanced input of port II and port III to the microstrip mode, and after absorption by the diamond-based power resistor 503 at the end of the microstrip, it blocks the signal path between port II and port III, thereby improving the isolation between port II and port III.

[0082] The specific assembly and installation sequence of this invention is as follows:

[0083] (1) The diamond-based power resistor 503 is placed on the tungsten copper carrier 502 by gold-tin eutectic bonding process;

[0084] (2) The tungsten copper carrier 502 is fixed in the groove of the base 5 of the load shielding box 2 by tin-lead welding process;

[0085] (3) Use conductive adhesive to bond the microwave printed circuit board 501 to the base 5 of the load shielding box 2;

[0086] (4) The rear end of the microwave printed circuit board 501 microstrip line and the input end of the diamond-based power resistor 503 are connected by multiple bonding alloy strips.

[0087] (5) Insert the metal probe 103 and the polytetrafluoroethylene sleeve 104 into the cylindrical cavity 101 of the lower housing 3; visually ensure that the interface between the middle and tail cylinders of the metal probe 103 is flush with the circular plane of the polytetrafluoroethylene sleeve 104, see reference. Figure 7 Use screws to pass through the through holes on the left and right sides of the lower housing 3 to fix the lower housing 3 to the heat sink or amplifier chassis;

[0088] (6) Place the base 5 of the load shielding box 2 tightly against the outer wall of the lower box 3 of the main shielding box 1. At this time, the tail of the metal probe 103 extends into the interior of the base 5. Use screws to pass through the through holes on the two mounting ears of the base 5 to fix the base 5 in the heat sink or power amplifier chassis.

[0089] (7) Use a soldering iron to solder the tail end of the metal probe 103 to the front end of the microstrip line of the microwave printed circuit board 501.

[0090] (8) The lower box 3 and the upper box 4 are precisely aligned by two pins 108 and fastened together by screws passing through the countersunk hole and the threaded hole; the base 5 and the cover plate 6 are fastened together by screws passing through the countersunk hole and the threaded hole, thus completing the assembly and installation of the present invention.

[0091] Those skilled in the art will recognize that the described embodiments are intended to help readers understand the principles of the invention and should be understood as not limiting the scope of protection of the invention to the described embodiments. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of the claims of the invention.

Claims

1. A high-power coplanar magic T-type metal probe, comprising a main shielding box and a load shielding box, both the main shielding box and the load shielding box having cavities inside, characterized in that, The main shielding box has one combining port on the combining side and two distributing ports on the distributing side. A straight waveguide extending into the main shielding box is provided at the combining port. A waveguide ET junction is provided at the end of the straight waveguide. A half-height waveguide-standard waveguide gradient structure is provided at each of the two branches of the waveguide ET junction. The end of the half-height waveguide-standard waveguide gradient structure is connected to an L-shaped waveguide. The end of the L-shaped waveguide extends to the corresponding distributing port. A boss is provided at the bottom of the waveguide ET junction, facing the straight waveguide. A cylindrical cavity is also provided on the distributing side of the main shielding box between the two distributing ports. The cylindrical cavity extends to the boss and communicates with the cavity of the waveguide ET junction. The straight waveguide, waveguide ET junction, half-height waveguide-standard waveguide gradient structure, L-shaped waveguide, and cylindrical cavity together constitute the cavity of the main shielding box. The cavity of the main shielding box has a left-right symmetrical structure. The load shielding box is located at the opening of the cylindrical cavity. A metal probe is installed inside the cylindrical cavity. The head of the metal probe extends from the boss and penetrates into the interior of the waveguide ET junction. The cavity of the load shielding box is an open cavity with a tungsten copper carrier at the end of the cavity. A diamond-based power resistor is placed on the tungsten copper carrier. A microwave printed circuit board is also placed inside the cavity. The microwave printed circuit board has a microstrip line. The front end of the microstrip line is connected to the end of the metal probe, and the rear end of the microstrip line is connected to the input terminal of the diamond-based power resistor. The grounded bottom surface of the diamond-based power resistor is connected to the tungsten copper carrier.

2. The high-power coplanar magic T-type metal probe according to claim 1, characterized in that, The main shielding box includes a lower box and an upper box. The cavity of the main shielding box is located in the lower box. The upper box is provided with multiple countersunk holes, and the lower box is provided with corresponding threaded holes. The upper box and the lower box are fixed by screws passing through the countersunk holes and threaded holes. The load shielding box includes a base and a cover plate. The cavity of the load shielding box is located in the base. The cover plate has multiple countersunk holes, and the base has corresponding threaded holes. The base and the cover plate are fixed by screws passing through the countersunk holes and threaded holes. Heat sinks are distributed on the side wall of the base.

3. The high-power coplanar magic T-type metal probe according to claim 1, characterized in that, The metal probe is divided into three sections: head, middle, and tail. The middle section serves as an impedance matching section, and the diameter of the head is greater than that of the tail, which is greater than that of the middle section. The cylindrical cavity is divided into two sections, with the diameter of the front section less than that of the rear section. The tail of the metal probe is fixed in the rear section of the cylindrical cavity by a polytetrafluoroethylene (PTFE) sleeve. The interface between the front and rear sections forms a barrier that prevents the PTFE sleeve from entering the waveguide ET junction. The tail of the metal probe serves as an inner conductor and together with the PTFE sleeve and the cylindrical cavity, forms a coaxial transmission line structure.

4. The high-power coplanar magic T-type metal probe according to claim 1, characterized in that, The combining port of the waveguide ET junction is a standard waveguide, and the two sliding ports are half-height waveguides.

5. A high-power coplanar magic T-type metal probe according to claim 1, characterized in that, The L-shaped waveguide consists of two standard straight waveguides that intersect perpendicularly, with the corner at the intersection cut at a 45° angle.

6. A high-power coplanar magic T-type metal probe according to claim 1, characterized in that, The half-height waveguide-standard waveguide transition structure is square horn-shaped, realizing the structural transformation from half-height waveguide to standard waveguide.

7. A high-power coplanar magic T-type metal probe according to claim 1, characterized in that, The microwave printed circuit board is bonded to the cavity with conductive adhesive. The diamond-based power resistor is the power resistor load. The diamond-based power resistor is placed on the tungsten copper carrier by gold-tin eutectic bonding process. The tungsten copper carrier is fixed in the groove at the end of the cavity by tin-lead bonding process. The rear end of the microstrip line is connected to the input end of the diamond-based power resistor by multiple bonding alloy strips.

8. A high-power coplanar magic T-type metal probe according to claim 1, characterized in that, The substrate of the microwave printed circuit board is an RT / duroid 5880 microwave dielectric board.

9. A high-power coplanar magic T-type metal probe according to claim 1, characterized in that, The main shielding box is made of 6063-T6 aluminum alloy with gold plating; the load shielding box is made of oxygen-free copper with gold plating.

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