Waveguide practical training system

Abstract

The utility model discloses a waveguide practical training system. The system comprises a microwave signal generator, a frequency meter, a microwatt power meter, a frequency selective amplifier, a variable attenuator, a fixed attenuator, a waveguide directional coupler, a magic T, a horn antenna, a measuring line, a sliding screw tuner, a crystal detector, a matched load, a coaxial waveguide converter, a short circuit plate, a reflecting plate, a straight waveguide and a frequency expander. According to the utility model, a product modular structure design is adopted, so that each student can understand the basic composition, working principle and simulation analysis of the microwave system, and the function and measurement method of each module in the system.

Description

Technical Field

[0001] The utility model belongs to the field of waveguides, and in particular relates to a waveguide training system. Background Art

[0002] Waveguides are primarily used as transmission lines at microwave frequencies, connecting microwave transmitters and receivers to their antennas in microwave ovens, radars, communications satellites, and microwave radio link equipment.

[0003] Common waveguide structures include parallel twin conductors, coaxial lines, parallel planar waveguides, rectangular waveguides, circular waveguides, microstrip lines, planar dielectric waveguides, and optical fibers. From the perspective of guiding electromagnetic waves, they can all be divided into an inner region and an outer region, with electromagnetic waves confined to the inner region (requiring that the principle of transverse resonance be satisfied within the waveguide cross-section).

[0004] To help students understand waveguide technology, many universities have incorporated related experimental projects into their accompanying experimental courses. However, despite the long-recognized advantages of waveguide measurement, the high cost of spectrum analyzers has kept them confined to research departments, making them rarely accessible to students. Furthermore, hardware limitations and the complexity of experimental procedures have made it difficult for students to grasp the basic structure and operating principles of waveguide systems. There is also a lack of experimental equipment that can enable students to systematically, concisely, portablely, and comprehensively understand the extensive knowledge in the waveguide field. Utility Model Content

[0005] In order to solve the above problems, the utility model proposes a waveguide training system, which includes a microwave signal generator, a frequency meter, a microwatt power meter, a frequency selective amplifier, a variable attenuator, a fixed attenuator, a waveguide directional coupler, a magic T, a horn antenna, a measuring line, a sliding screw tuner, a crystal detector, a matching load, a coaxial waveguide converter, a short-circuit plate, a reflector, a straight waveguide, and a frequency extender. The system is used to realize waveguide detector measurement, frequency, waveguide wavelength and free space wavelength measurement, waveguide cavity Q value measurement, standing wave measurement, impedance measurement, directional coupler measurement, attenuator measurement, and magic T measurement experiments.

[0006] Specifically, the frequency meter includes a first rectangular waveguide, a first flange, a cylindrical resonant cavity, a tuning mechanism and a frequency reading. The first flanges are provided at both ends of the first rectangular waveguide. One end of the cylindrical resonant cavity is installed on the H-plane of the first rectangular waveguide. The first rectangular waveguide and the cylindrical resonant cavity are connected by a kidney-shaped small hole combination. The other end of the cylindrical resonant cavity is installed with a tuning mechanism. When the wavelength of the input signal is equal to the wavelength of the cylindrical resonant cavity, the cylindrical resonant cavity absorbs the maximum energy of the input signal, and the energy of the output end signal of the waveguide is the minimum. When the frequency of the input signal is unknown, the tuning mechanism is adjusted to minimize the energy of the output end signal. At this time, the frequency reading displayed on the frequency meter is the input signal frequency.

[0007] Specifically, the variable attenuator includes: a second rectangular waveguide, a second flange, an adjustment mechanism and a second attenuation plate; second flanges are provided at both ends of the second rectangular waveguide, a second attenuation plate is installed on the E surface of the second rectangular waveguide, two connecting rods are installed on the second attenuation plate, and the connecting rods are connected to the adjustment mechanism through two small holes opened on the H surface inside the second rectangular waveguide. The adjustment mechanism causes the second attenuation plate to move on the E surface inside the second rectangular waveguide to change the attenuation amount. The disk of the adjustment mechanism is engraved with the attenuation amount corresponding to the second attenuation plate in the second rectangular waveguide.

[0008] Specifically, the fixed attenuator includes: a third rectangular waveguide, a third flange, and a third attenuation plate. The third flanges are provided at both ends of the third rectangular waveguide, and a third attenuation plate is installed at the center of the E-plane of the third rectangular waveguide. The built-in third attenuation plate is wedge-shaped.

[0009] Specifically, the waveguide directional coupler includes a fourth main waveguide, a sub-waveguide, a fourth flange, and a terminal load. The fourth main waveguide is in the shape of a hollow rectangular tube, with a sub-waveguide arranged above it. One end of the sub-waveguide is closely attached to the fourth main waveguide, and the other end is bent away from the fourth main waveguide. Fourth flanges are provided at both ends of the fourth main waveguide and the bent part of the sub-waveguide.

[0010] Specifically, the magic T consists of a T-shaped waveguide and an HT branch waveguide. The horizontal direction of the T-shaped waveguide is the fifth main waveguide, and the vertical direction is the ET branch waveguide. The HT branch waveguide is arranged in the middle of the fifth main waveguide and is perpendicular to the fifth main waveguide and the ET branch waveguide. The two ends of the fifth main waveguide and the ends of the ET branch waveguide and the HT branch waveguide away from the fifth main waveguide are all provided with a fifth flange.

[0011] Specifically, the horn antenna includes a sixth rectangular waveguide, a sixth flange, and a horn mouth. One end of the sixth rectangular waveguide is provided with a sixth flange, and the other end is provided with a horn mouth. The horn antenna linearly expands the E surface and H surface of the sixth rectangular waveguide relative to the central axis.

[0012] Specifically, the measuring line includes a seventh rectangular waveguide, a seventh flange, a seventh slider, a crystal detector frame, an electronic scale, and a bracket. The seventh rectangular waveguide is arranged between two parallel quadrilateral brackets and is located on the upper part of the quadrilateral bracket. Two seventh flanges are respectively arranged on the outer sides of the quadrilateral brackets. A slide rail is provided on the front side of the quadrilateral bracket, and the seventh slider is slidably installed on the slide rail. The seventh slider is provided with an electronic scale, and the seventh rectangular waveguide is provided with a crystal detector frame.

[0013] Specifically, the sliding screw adjuster includes an eighth rectangular waveguide, an eighth flange, an eighth slider, a micrometer adjuster, and a ruler. A slot is opened in the center of the E-surface of the eighth rectangular waveguide. The eighth slider is slidably installed on the eighth rectangular waveguide. Eighth flanges are provided at both ends of the eighth rectangular waveguide. The micrometer adjuster is installed on the eighth slider through a slider seat. A metal rod is provided at the top of the micrometer adjuster. The metal rod passes through the micrometer adjuster, the slider seat, and the eighth slider in sequence to reach the slot opened in the center of the E-surface of the eighth rectangular waveguide.

[0014] Specifically, the crystal detector includes: a ninth rectangular waveguide, a ninth flange, a waveguide detection bracket, a ninth short-circuit plate 093, and a BNC output connector; one end of the ninth rectangular waveguide is connected to the ninth flange, and the other end is provided with a ninth short-circuit plate; a waveguide detection bracket is provided on the upper side of the ninth rectangular waveguide, and the waveguide detection bracket is provided with a BNC output connector; a crystal detector diode is installed in the waveguide detection bracket, one end of the crystal detector diode is connected to the central inner conductor of the BNC output connector, and the other end is connected to the waveguide wall of the ninth rectangular waveguide via an adjustment bolt.

[0015] Specifically, the matching load includes: a tenth rectangular waveguide, a tenth flange, and a tenth load; two ends of the tenth rectangular waveguide are connected to the tenth flange and the tenth load respectively.

[0016] Specifically, the connection method for the waveguide detector measurement experiment is: the signal generator, coaxial waveguide converter, fixed attenuator, detector, and frequency-selective amplifier are connected in sequence; the connection method for the frequency, waveguide wavelength, and free space wavelength measurement experiments is: the signal generator, variable attenuator, frequency meter, measurement line, and straight waveguide are connected in sequence, and the measurement line is also connected to the frequency-selective amplifier; the connection method for the waveguide cavity Q value measurement experiment is: the signal generator, variable attenuator, frequency meter, coaxial waveguide converter, and microwatt power meter are connected in sequence; the connection method for the standing wave measurement experiment is: the signal generator, coaxial waveguide converter, variable attenuator, measurement line, sliding screw adapter, and matching load are connected in sequence, and the frequency-selective amplifier is connected to the measurement line; The connection method of the impedance measurement experiment is: the signal generator, variable attenuator, wavelength meter, measurement line, sliding screw adapter, and matching load are connected in sequence, and the frequency-selective amplifier is connected to the measurement line; the connection method of the directional coupler measurement experiment is: the signal generator, variable attenuator, directional coupler, and matching load are connected in sequence, and the directional coupler is also connected to the frequency-selective device through a detector; the connection method of the attenuator measurement experiment is: the signal generator, variable attenuator, detector, and frequency-selective amplifier are connected in sequence; the connection method of the magic T measurement experiment is: the signal generator, fixed attenuator, variable attenuator, magic T, and detector are connected in sequence, and the magic T is also connected to the microwatt power meter through a coaxial waveguide converter, and the magic T is also connected to the matching terminal.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) Microwave signal source: 8.0-12.4GHz solid-state digital signal source, power dynamic range -50 to +20dBm; built-in modulation square wave: 400Hz to 4KHz (1Hz continuously adjustable)

[0019] (2) The frequency meter adopts an absorption-type high-Q resonant cavity (Q value greater than 800), which has a good feel and high accuracy;

[0020] (3) The variable attenuator adopts direct reading type, which is highly reliable and easy to adjust;

[0021] (4) The measuring line adopts a waveguide slider structure with a sliding distance of >140mm and an embedded digital vernier caliper, which makes the reading convenient and accurate;

[0022] (5) Equipped with AT-F9 frequency extender, the frequency extender can be used to measure the f = 8.2-12.4GHz signal spectrum using a 3GHz spectrum analyzer, reducing the frequency requirements of the spectrum analyzer for X-band frequency domain measurements;

[0023] (6) Special portable instrument box for easy transportation, storage and management.

[0024] (7) The product adopts modular structure design to enable each student to understand the basic structure, working principle, simulation analysis, function and measurement method of each module in the system.

[0025] (8) The modules can be installed and combined to perform more than ten different experiments, allowing each student to master different waveguide measurement methods more deeply through different combination modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of a frequency meter according to an embodiment of the present utility model.

[0027] Figure 2 It is a structural diagram of a variable attenuator according to an embodiment of the present utility model.

[0028] Figure 3 It is a structural diagram of a fixed attenuator according to an embodiment of the present utility model.

[0029] Figure 4 It is a structural diagram of a waveguide directional coupler according to an embodiment of the present utility model.

[0030] Figure 5 It is a structural diagram of the magic T of an embodiment of the present utility model.

[0031] Figure 6 It is a structural diagram of the horn antenna of an embodiment of the present utility model.

[0032] Figure 7 It is a structural diagram of a measuring line according to an embodiment of the present utility model.

[0033] Figure 8 It is a structural diagram of a sliding screw dispenser according to an embodiment of the present utility model.

[0034] Figure 9 It is a structural diagram of a crystal detector according to an embodiment of the present utility model.

[0035] Figure 10 It is a structural diagram of a matching load according to an embodiment of the present utility model.

[0036] Figure 11 It is a structural diagram of a coaxial waveguide converter according to an embodiment of the present utility model.

[0037] Figure 12 It is a structural diagram of a short-circuit plate according to an embodiment of the present utility model.

[0038] Figure 13 It is a structural diagram of a reflector according to an embodiment of the present invention.

[0039] Figure 14 This is a measurement connection diagram of a waveguide detector according to an embodiment of the present utility model.

[0040] Figure 15 This is a connection diagram of a measurement experiment for frequency, waveguide wavelength, and free space wavelength according to an embodiment of the present utility model.

[0041] Figure 16 This is a connection diagram for measuring the Q value of a waveguide cavity according to an embodiment of the present utility model.

[0042] Figure 17 This is a standing wave measurement connection diagram of an embodiment of the present utility model.

[0043] Figure 18 This is an impedance measurement connection diagram of an embodiment of the present utility model.

[0044] Figure 19 This is a measurement connection diagram of a directional coupler according to an embodiment of the present utility model.

[0045] Figure 20 This is a measurement connection diagram of an attenuator according to an embodiment of the present utility model.

[0046] Figure 21 This is a magic T measurement connection diagram of an embodiment of the present utility model. DETAILED DESCRIPTION

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0048] The waveguide training system provided in this embodiment is specifically the AT3000 waveguide training system. Unlike other waveguide and microwave training systems, the AT3000 waveguide training system is primarily based on waveguide technology, measurement line principles, frequency-selective amplifiers, and precision measurements using a microwatt power meter. The device is equipped with an 8.0-12.4 GHz signal generator, a waveguide cavity frequency meter, a microwatt power meter, a frequency-selective amplifier, a variable attenuator, a fixed attenuator, a directional coupler, a magic T, a horn antenna, a measurement line, a sliding screw tuner, a crystal detector, a matching load, a coaxial waveguide converter, a short-circuit plate, a reflector, a straight waveguide, an F9 frequency extender, an oscilloscope, a spectrum analyzer, and the like.

[0049] This system is suitable for use in colleges and universities, scientific research institutions, microwave communications, radar stations, etc. It has the characteristics of compact structure, complete equipment, and high cost performance.

[0050] The AT3000 microwave experimental system includes: a microwave signal generator, a frequency meter, a microwatt power meter, a frequency selective amplifier, a variable attenuator, a fixed attenuator, a waveguide directional coupler, a magic T, a horn antenna, a measuring line, a sliding screw tuner, a crystal detector, a matching load, a coaxial waveguide converter, a short-circuit plate, a reflector, a straight waveguide, and a frequency extender.

[0051] 1. (Microwave) signal generator AT1433: 8.0-12.4GHz, -50-20dBm, built-in modulated square wave 400Hz-4kHz (1Hz continuously adjustable).

[0052] 2. Frequency counter (AT8272)

[0053] Frequency meter structure Figure 1 As shown in the figure: a first rectangular waveguide 011, a first flange 012, a cylindrical resonant cavity 013, a tuning mechanism 014, and a frequency readout 015. First flanges 012 are provided at both ends of the first rectangular waveguide 011. One end of the cylindrical resonant cavity 013 is mounted on the H-surface of the first rectangular waveguide 011, with a kidney-shaped aperture between them. The other end is mounted with the tuning mechanism 014. When the wavelength of the input signal is equal to the wavelength of the cylindrical resonant cavity 013, the cylindrical resonant cavity 013 absorbs the maximum energy of the input signal, and the energy of the signal at the waveguide's output is minimized. When the input signal frequency is unknown, the tuning mechanism 014 is adjusted to minimize the energy of the output signal. At this point, the frequency reading 015 displayed on the frequency meter is the input signal frequency.

[0054] The main technical parameters of the frequency meter are: frequency range: f=8.2-12.4GHz; loaded Q value: Q≥800; accuracy ≤0.3%.

[0055] 3. Microwatt power meter AT437D: frequency range 10MHz to 12.4GHz, dynamic range: -60dBm to +20dBm.

[0056] 4. Variable attenuator (AT8352)

[0057] The variable attenuator structure is as follows: Figure 2 As shown in the figure: a second rectangular waveguide 021, a second flange 022, and an adjustment mechanism 023.

[0058] Second flanges 022 are provided at both ends of the second rectangular waveguide 021. A second attenuation plate is mounted on the E-surface of the second rectangular waveguide 021. Two connecting rods are mounted on the second attenuation plate. The connecting rods are connected to an adjustment mechanism 023 through two small holes opened on the H-surface inside the second rectangular waveguide 021. The adjustment mechanism 023 moves the second attenuation plate on the E-surface inside the second rectangular waveguide 021 to change the attenuation. The disc of the adjustment mechanism 023 is engraved with the attenuation corresponding to the second attenuation plate inside the second rectangular waveguide 021.

[0059] Main technical parameters of variable attenuator: frequency range: f=8.2-12.4GHz; input standing wave ratio ≤1.25; initial attenuation ≤1dB; variable attenuation 0~20dB.

[0060] 5. Fixed attenuator AT8353 (6dB, 20dB)

[0061] Fixed attenuator structure Figure 3 As shown in the figure: a third rectangular waveguide 031 and a third flange 032. The third flanges 032 are provided at both ends of the third rectangular waveguide 031. A third attenuation plate is installed at the center of the E-plane of the third rectangular waveguide 031. The built-in third attenuation plate is wedge-shaped.

[0062] Main technical parameters of fixed attenuator: 1. Frequency range: f = 8.2-12.4GHz; 2. Input standing wave ratio ≤ 1.15; 3. Attenuation 6 ± 2.5dB 20 ± 5dB

[0063] 6. Waveguide directional coupler AT8261

[0064] Structure of waveguide directional coupler Figure 4 As shown in the figure: a fourth main waveguide 041 , a secondary waveguide 042 , a fourth flange 043 , and a terminal load 044 .

[0065] The fourth main waveguide 041 is in the shape of a hollow rectangular tube, with a sub-waveguide 042 arranged above it. One end of the sub-waveguide 042 is closely attached to the fourth main waveguide 041, and the other end is bent away from the fourth main waveguide 041. Fourth flanges 043 are provided at both ends of the fourth main waveguide 041 and the bent part of the sub-waveguide 042.

[0066] The main technical parameters of the waveguide directional coupler are: 1. Frequency range: f = 8.2-12.4GHz; 2. Input standing wave ratio of the main waveguide and the auxiliary waveguide ≤ 1.5; 3. Coupling degree C = 10±2dB; 4. Directivity D ≥ 20dB; 5. Insertion loss L ≤ 1dB.

[0067] 7. Magic T AT8311

[0068] The structure of the magic T is as follows Figure 5As shown, it consists of a rectangular waveguide ET and a HT branch, in the figure: a fifth main waveguide 051 , an ET branch waveguide 052 , a HT branch waveguide 053 , and a fifth flange 054 .

[0069] The magic T consists of a T-shaped waveguide and an HT branch waveguide 053. The T-shaped waveguide is connected to the fifth main waveguide 051 horizontally and to the ET branch waveguide 052 vertically. The HT branch waveguide 053 is arranged in the middle of the fifth main waveguide 051 and is perpendicular to the fifth main waveguide 051 and the ET branch waveguide 052. Fifth flanges 054 are provided at both ends of the fifth main waveguide 051 and at the ends of the ET branch waveguide 052 and the HT branch waveguide 053 away from the fifth main waveguide 051.

[0070] The main technical parameters of the magic T: frequency f range is 8.2-12.4GHz; input standing wave ratio of each port ≤2; isolation ≥30dB; power distribution unevenness of ports A and B ≤0.5dB.

[0071] 8. Horn antenna AT8912

[0072] The structure of the horn antenna is as follows Figure 6 As shown in the figure: a sixth rectangular waveguide 061, a sixth flange 062, and a horn mouth 063. One end of the sixth rectangular waveguide 061 is provided with a sixth flange 062, and the other end is provided with a horn mouth 063; the horn antenna linearly expands the E surface and the H surface of the sixth rectangular waveguide 061 relative to the central axis.

[0073] The main technical parameters of the horn antenna are: 1. Frequency range: f=8.2-12.4GHz; 2. The input standing wave ratio of the port is ≤1.5.

[0074] 9. Measuring line AT3632

[0075] The structure of the measuring line is as follows Figure 7 As shown in the figure: the seventh rectangular waveguide 071, the seventh flange 072, the seventh slider 073, the crystal detector frame 074, the electronic ruler 075, and the bracket 076. It adopts a waveguide and slider structure, has no tuning mechanism, and has a sliding distance of 140mm.

[0076] The seventh rectangular waveguide 071 is arranged between two parallel quadrilateral brackets 076, located at the upper part of the quadrilateral bracket 076. Two seventh flanges 072 are respectively provided on the outer sides of the quadrilateral bracket 076. A slide rail is provided on the front side of the quadrilateral bracket 076, and a seventh slider 073 is slidably installed on the slide rail. The seventh slider 073 is provided with an electronic scale 075. The seventh rectangular waveguide 071 is provided with a crystal detector bracket 074.

[0077] The main technical parameters of the measuring line are: 1. Operating frequency range: f = 8.2-12.4 GH; 2. Residual standing wave ratio ≤ 1.05.

[0078] 10. Sliding screw dispenser AT8222

[0079] The structure of the sliding screw mixer is as follows Figure 8 As shown in the figure: the eighth rectangular waveguide 081, the eighth flange 082, the eighth slider 083, the micrometer adjuster 084, and the scale 085. It can be seen from the figure that it adopts a waveguide slider structure, a slot is opened in the center of the E-plane of the eighth rectangular waveguide 081, the eighth slider 083 is slidably installed on the eighth rectangular waveguide 081, and the eighth flanges 082 are provided at both ends of the eighth rectangular waveguide 081. The micrometer adjuster 084 is installed on the eighth slider 083 through the slider seat, and a metal rod is provided at the top of the micrometer adjuster 084. The metal rod passes through the micrometer adjuster 084, the slider seat, and the eighth slider 083 in sequence to reach the slot opened in the center of the E-plane of the eighth rectangular waveguide 081.

[0080] The main technical parameters of the sliding screw dispenser are: 1. Operating frequency range: f=8.2-12.4GHz; 2. Standing wave ratio adjustment range: 1.05-20; 3. The moving distance of the eighth slider 083 is ≥40mm.

[0081] 11. Crystal detector AT8232

[0082] The structure of the crystal detector is as follows Figure 9 As shown in the figure: a ninth rectangular waveguide 095, a ninth flange 091, a waveguide detector bracket 092, a ninth short-circuit plate 093, and a BNC output connector 094. One end of the ninth rectangular waveguide 095 is connected to the ninth flange 091, and the other end is provided with the ninth short-circuit plate 093. A waveguide detector bracket 092 is provided on the upper side of the ninth rectangular waveguide 095, and a BNC output connector 094 is provided on the waveguide detector bracket 092. A crystal detector diode is installed within the waveguide detector bracket 092. One end of the crystal detector diode is connected to the central inner conductor of the BNC output connector 094, and the other end is connected to the waveguide wall of the ninth rectangular waveguide 095 via an adjusting bolt.

[0083] The main technical parameters of the crystal detector are: 1. Operating frequency range: f=8.2-12.4GHz; 2. Input standing wave ratio ≤1.5; 3. Detection sensitivity >1.5mV / μW.

[0084] 12. Matching load AT8252

[0085] The structure of the matching load is as follows Figure 10 As shown in the figure: a tenth rectangular waveguide 101, a tenth flange 102, and a tenth load 103.

[0086] Two ends of the tenth rectangular waveguide 101 are connected to a tenth flange 102 and a tenth load 103 respectively.

[0087] The main technical parameters of the matching load: 1. Frequency range: f = 8.2-12.4GHz; 2. Input standing wave ratio of the port ≤ 1.08; 3. Withstand power P max =5mW.

[0088] 13. Coaxial waveguide converter AT8392

[0089] The structure of the coaxial waveguide converter is as follows Figure 11 As shown in the figure: an eleventh rectangular waveguide 111, an eleventh flange 112, and an N-type coaxial connector 113.

[0090] An N-type coaxial connector 113 is provided on the side of the eleventh rectangular waveguide 111, extending into its E-wall. The end of the inner conductor of the N-type coaxial connector 113 is elliptical to increase the passband and power capacity. One end of the eleventh rectangular waveguide 111 is a short-circuit board, and the other end is provided with an eleventh flange 112. The distance d between the short-circuit board and the inner conductor of the N-type coaxial connector 113 is d, where d = λ0 / 4, where λ0 is the center frequency waveguide wavelength.

[0091] The main technical parameters of the coaxial waveguide converter are: 1. Frequency range: f = 8.2-12.4GHz; 2. The input standing wave ratio of the port is ≤1.5.

[0092] 14. Short circuit board AT8381

[0093] Short circuit board structure Figure 12 Shown: It is an FJB-100 standard waveguide flange plate.

[0094] The main technical parameters of the short-circuit board: standing wave ratio>10.

[0095] 15. Reflector: Figure 13 As shown, the reflector is a polyester fiberglass plate with foil on both sides.

[0096] 16. Straight waveguide AT8321:

[0097] Straight waveguide: It consists of an FJB-100 standard waveguide and two FJB-100 standard flanges.

[0098] The main technical parameters of the straight waveguide: the input standing wave ratio of the port is ≤1.08, and the insertion loss is ≤0.5dB.

[0099] 17. Frequency selective amplifier AT3892;

[0100] (1) Operating frequency: 1000Hz, adjustable range not less than 40Hz. (2) Passband: Continuously adjustable from 16Hz to 40Hz. (3) Sensitivity: Not less than 0.5μV when the impedance is 200kΩ, the meter is at full scale deflection and the "bandwidth selection" is set to 16Hz passband. (4) Meter scale: Voltage value 0-1000mV, decibel value 0-10dB, standing wave ratio 1-4, 3-10, nonlinear error less than ±5% of full scale. (5) Amplifier range: "Amplification selection" switch 0-60dB, step 10dB±0.5dB, "Gain" knob 0-5dB±0.2dB continuously adjustable. (6) Input impedance: 200kΩ (7) Power supply: ~220V, 50Hz, 20W (8) External dimensions: width × height × depth = 250mm × 110mm × 250mm (9) Weight: 3kg

[0101] 18. Frequency extender: AT-F9: Local oscillator frequency F0: 8500MHz ~ 9100MHz, input frequency: 7500MHz ~ 12400MHz, input power: <20dBm, output frequency: 0MHz ~ 3000MHz

[0102] 19. Special instrument box, used to place the above devices, with one hole for each device.

[0103] The above rectangular waveguides are all standard three-centimeter rectangular waveguides.

[0104] The above-mentioned devices of this embodiment can be assembled and combined to conduct more than ten different experiments, including the following experiments.

[0105] Waveguide detector measurement experiments, such as Figure 14 As shown, the signal generator, coaxial waveguide converter, fixed attenuator, detector, and frequency selective amplifier are connected in sequence.

[0106] Measurement experiments of frequency, waveguide wavelength λg and free space wavelength λ, such as Figure 15 As shown, a signal generator, a variable attenuator, a frequency meter, a measuring line, and a straight waveguide are connected in sequence, and the measuring line is also connected to a frequency-selective amplifier.

[0107] Waveguide cavity Q value measurement experiment, such as Figure 16 As shown, a signal generator, a variable attenuator, a frequency meter, a coaxial waveguide converter, and a microwatt power meter are connected in sequence.

[0108] Power measurement experiment, the experimental connection diagram is the same as Figure 16 .

[0109] Standing wave measurement experiments, such as Figure 17 As shown, a signal generator, a coaxial waveguide converter, a variable attenuator, a measuring line, a sliding screw adapter, and a matching load are connected in sequence, and a frequency selective amplifier is connected to the measuring line.

[0110] Impedance measurement experiments, such as Figure 18 As shown, a signal generator, a variable attenuator, a wavelength meter, a measuring line, a sliding screw adapter, and a matching load are connected in sequence, and a frequency selective amplifier is connected to the measuring line.

[0111] Directional coupler measurement experiments, such as Figure 19 As shown, a signal generator, a variable attenuator, a directional coupler, and a matching load are connected in sequence, and the directional coupler is also connected to a frequency selector through a detector.

[0112] Attenuator measurement experiments, such as Figure 20 As shown, the signal generator, variable attenuator, detector, and frequency selective amplifier are connected in sequence.

[0113] Magic T measurement experiment, such as Figure 21 As shown, the signal generator, fixed attenuator (6dB), variable attenuator, magic T, and detector are connected in sequence. The magic T is also connected to a microwatt power meter through a coaxial / waveguide converter, and the magic T is also connected to a matching terminal.

[0114] This example includes a microwave signal source (8.0-12.4 GHz), a JB-100 three-centimeter waveguide, a waveguide cavity frequency meter, a waveguide variable attenuator, a waveguide measurement line, a tuner, a load, a pair of horn antennas, a coaxial waveguide converter, a waveguide detector, and other components. By measuring various waveguide components and building a microwave transmitting and receiving system, and through hands-on experiments, students can gain a deeper understanding of waveguide components and master the characteristics and measurement methods of signal frequency, power, wavelength, standing wave ratio, impedance, attenuation, and other aspects in waveguide transmission.

[0115] The waveguide training system of this embodiment is equipped with a dedicated instrument box (one module, one hole position) for easy storage and transportation.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A waveguide training system, characterized in that: The system includes: a microwave signal generator, a frequency meter, a microwatt power meter, a frequency selective amplifier, a variable attenuator, a fixed attenuator, a waveguide directional coupler, a magic T, a horn antenna, a measuring line, a sliding screw tuner, a crystal detector, a matching load, a coaxial waveguide converter, a short-circuit plate, a reflector, a straight waveguide, and a frequency extender, and is used to implement waveguide detector measurement, frequency, waveguide wavelength and free space wavelength measurement, waveguide cavity Q value measurement, standing wave measurement, impedance measurement, directional coupler measurement, attenuator measurement, and magic T measurement experiments; The connection method for the waveguide detector measurement experiment is: signal generator, coaxial waveguide converter, fixed attenuator, detector, and frequency-selective amplifier are connected in sequence; the connection method for the frequency, waveguide wavelength, and free space wavelength measurement experiment is: signal generator, variable attenuator, frequency meter, measurement line, and straight waveguide are connected in sequence, and the measurement line is also connected to the frequency-selective amplifier; the connection method for the waveguide cavity Q value measurement experiment is: signal generator, variable attenuator, frequency meter, coaxial waveguide converter, and microwatt power meter are connected in sequence; the connection method for the standing wave measurement experiment is: signal generator, coaxial waveguide converter, variable attenuator, measurement line, sliding screw adapter, and matching load are connected in sequence, and the frequency-selective amplifier is connected to the measurement line; impedance The connection method of the measurement experiment is: the signal generator, variable attenuator, wavelength meter, measurement line, sliding screw adapter, and matching load are connected in sequence, and the frequency-selective amplifier is connected to the measurement line; the connection method of the directional coupler measurement experiment is: the signal generator, variable attenuator, directional coupler, and matching load are connected in sequence, and the directional coupler is also connected to the frequency-selective device through a detector; the connection method of the attenuator measurement experiment is: the signal generator, variable attenuator, detector, and frequency-selective amplifier are connected in sequence; the connection method of the magic T measurement experiment is: the signal generator, fixed attenuator, variable attenuator, magic T, and detector are connected in sequence, and the magic T is also connected to the microwatt power meter through a coaxial waveguide converter, and the magic T is also connected to the matching terminal.

2. The waveguide training system according to claim 1, characterized in that: The frequency meter comprises a first rectangular waveguide (011), a first flange (012), a cylindrical resonant cavity (013), a tuning mechanism (014) and a frequency reading (015). The first flanges (012) are provided at both ends of the first rectangular waveguide (011). One end of the cylindrical resonant cavity (013) is mounted on the H-surface of the first rectangular waveguide (011). A kidney-shaped small hole is provided between the first rectangular waveguide (011) and the cylindrical resonant cavity (013). The other end of the cylindrical resonant cavity (013) is mounted with a tuning mechanism (014). When the wavelength of the input signal is equal to the wavelength of the cylindrical resonant cavity (013), the cylindrical resonant cavity (013) absorbs the maximum energy of the input signal, and the energy of the output end signal of the waveguide is the minimum. When the frequency of the input signal is unknown, the tuning mechanism (014) is adjusted to minimize the energy of the output end signal. At this time, the frequency reading (015) displayed on the frequency meter is the input signal frequency.

3. The waveguide training system according to claim 1, characterized in that: The variable attenuator comprises: a second rectangular waveguide (021), a second flange (022), an adjustment mechanism (023) and a second attenuation plate; the second flanges (022) are provided at both ends of the second rectangular waveguide (021); the second attenuation plate is installed on the E surface of the second rectangular waveguide (021); two connecting rods are installed on the second attenuation plate; the connecting rods are connected to the adjustment mechanism (023) through two small holes opened on the H surface inside the second rectangular waveguide (021); the adjustment mechanism (023) moves the second attenuation plate on the E surface inside the second rectangular waveguide (021) to change the attenuation amount; the disc of the adjustment mechanism (023) is engraved with the attenuation amount corresponding to the second attenuation plate in the second rectangular waveguide (021).

4. The waveguide training system according to claim 1, characterized in that: The fixed attenuator comprises: a third rectangular waveguide (031), a third flange (032), and a third attenuation plate; the third flanges (032) are provided at both ends of the third rectangular waveguide (031); the third attenuation plate is installed at the center of the E-plane of the third rectangular waveguide (031); and the built-in third attenuation plate is wedge-shaped.

5. The waveguide training system according to claim 1, characterized in that: The waveguide directional coupler comprises a fourth main waveguide (041), a subsidiary waveguide (042), a fourth flange (043), and a terminal load (044). The fourth main waveguide (041) is in the shape of a hollow rectangular parallelepiped pipe, and a subsidiary waveguide (042) is arranged above the fourth main waveguide (041). One end of the subsidiary waveguide (042) is closely attached to the fourth main waveguide (041), and the other end is bent in a direction away from the fourth main waveguide (041). The fourth flange (043) is provided at both ends of the fourth main waveguide (041) and the bent portion of the subsidiary waveguide (042).

6. The waveguide training system according to claim 1, characterized in that: The magic T is composed of a T-shaped waveguide and an HT branch waveguide (053). The T-shaped waveguide is a fifth main waveguide (051) in the horizontal direction and an ET branch waveguide (052) in the vertical direction. The HT branch waveguide (053) is arranged in the middle of the fifth main waveguide (051) and is perpendicular to the fifth main waveguide (051) and the ET branch waveguide (052). Both ends of the fifth main waveguide (051) and the ends of the ET branch waveguide (052) and the HT branch waveguide (053) away from the fifth main waveguide (051) are all provided with a fifth flange (054).

7. The waveguide training system according to claim 1, characterized in that: The horn antenna comprises a sixth rectangular waveguide (061), a sixth flange (062), and a horn mouth (063); one end of the sixth rectangular waveguide (061) is provided with the sixth flange (062), and the other end is provided with the horn mouth (063); the horn antenna linearly expands the E surface and the (H) surface of the sixth rectangular waveguide (061) relative to the central axis.

8. The waveguide training system according to claim 1, characterized in that: The measuring line comprises a seventh rectangular waveguide (071), a seventh flange (072), a seventh slider (073), a crystal detector frame (074), an electronic scale (075), and a bracket (076); the seventh rectangular waveguide (071) is arranged between two parallel quadrilateral brackets (076) and located on the upper part of the quadrilateral brackets (076); two seventh flanges (072) are respectively arranged on the outer sides of the quadrilateral brackets (076); a slide rail is arranged on the front side of the quadrilateral brackets (076); the seventh slider (073) is slidably mounted on the slide rail; the electronic scale (075) is arranged on the seventh slider (073); and the crystal detector frame (074) is arranged on the seventh rectangular waveguide (071).

9. The waveguide training system according to claim 1, characterized in that: The sliding screw dispenser comprises an eighth rectangular waveguide (081), an eighth flange (082), an eighth slider (083), a micrometer regulator (084), and a scale (085). A slot is provided at the center of the E surface of the eighth rectangular waveguide (081). The eighth slider (083) is slidably mounted on the eighth rectangular waveguide (081). Eighth flanges (082) are provided at both ends of the eighth rectangular waveguide (081). The micrometer regulator (084) is mounted on the eighth slider (083) through a slider seat. A metal rod is provided at the top of the micrometer regulator (084). The metal rod sequentially penetrates the micrometer regulator (084), the slider seat, and the eighth slider (083) to reach the slot provided at the center of the E surface of the eighth rectangular waveguide (081).

10. The waveguide training system according to claim 1, characterized in that: The crystal detector comprises: a ninth rectangular waveguide (095), a ninth flange (091), a waveguide detection frame (092), a ninth short-circuit plate (093), and a BNC output connector (094); one end of the ninth rectangular waveguide (095) is connected to the ninth flange (091), and the other end is provided with the ninth short-circuit plate (093); the upper side of the ninth rectangular waveguide (095) is provided with a waveguide detection frame (092), and the waveguide detection frame (092) is provided with a BNC output connector (094); a crystal detection diode is installed in the waveguide detection frame (092), one end of the crystal detection diode is connected to the central inner conductor of the BNC output connector (094), and the other end is connected to the waveguide wall of the ninth rectangular waveguide (095) through an adjusting bolt.

11. The waveguide training system according to claim 1, characterized in that: The matching load comprises: a tenth rectangular waveguide (101), a tenth flange (102), and a tenth load (103); two ends of the tenth rectangular waveguide (101) are respectively connected to the tenth flange (102) and the tenth load (103).

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