Radio frequency teaching training system

Abstract

The utility model discloses a radio frequency teaching training system. The system comprises two voltage-controlled oscillators, one frequency mixer, one circulator, one directional coupler, one power divider, one hybrid ring device, one PIN switch, one PIN modulator, four filters, one bias line, one 3dB bridge, two radio frequency amplifiers, two attenuators, one coaxial detector, two microstrip antennas, one measuring line and five calibration parts. According to the utility model, all the modules adopt the microstrip circuit design, and the upper cover plate adopts the transparent organic glass, so that the structures of all the microstrip circuits can be observed clearly, and students can be better helped to understand and master the basic composition and working principle of a related radio frequency system.

Description

Technical Field

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

[0002] For the most important fields such as RF communications, sensing, and signal processing, the frequency domain contains a lot of important information that is inconvenient to represent or difficult to measure in the time domain. Therefore, using a spectrum analyzer with high sensitivity and wide dynamic range, we can easily measure low-level amplitude-modulated, frequency-modulated, and pulse-modulated RF signals. We can also measure carrier frequency, modulation frequency, modulation level, and modulation distortion. At the same time, we can also easily detect the frequency conversion loss, isolation, and distortion characteristics of frequency conversion devices.

[0003] To help students understand RF knowledge, many universities have incorporated related experimental projects into their accompanying lab courses. However, despite the long-recognized advantages of spectrum 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 make it difficult for students to understand and grasp the basic structure and operating principles of RF systems simply by observing the structure of the entire circuit. There is also a lack of experimental equipment that can enable students to systematically, concisely, portable, and comprehensively understand the vast knowledge in the RF field. Summary of the Invention

[0004] In order to solve the above problems, the utility model proposes a radio frequency teaching and training system, including 2 voltage-controlled oscillators, 1 mixer, 1 circulator, 1 directional coupler, 1 power divider, 1 hybrid circulator, 1 PIN switch, 1 PIN modulator, 1 low-pass filter, 1 high-pass filter, 1 band-pass filter, 1 band-stop filter, 1 bias line, 1 circular resonator, 1 branch coupler, 2 radio frequency amplifiers, 2 attenuators, 1 coaxial detector, 2 microstrip antennas, 1 measuring line, and 5 calibration pieces, which are used to realize 20 experiments, including voltage-controlled oscillator experiments, mixer experiments, circulator experiments, directional coupler experiments, Experiments, attenuator experiments, power divider experiments, hybrid circulator experiments, PIN switch experiments, PIN modulator experiments, coaxial detector experiments, filter experiments, circular resonator experiments, branch coupler experiments, RF amplifier experiments, measurement line experiments, microstrip antenna experiments, RF front-end transmitter / receiver experiments; voltage-controlled oscillator, mixer, circulator, directional coupler, power divider, hybrid circulator, PIN switch, PIN modulator, low-pass filter, high-pass filter, band-pass filter, band-stop filter, bias line, circular resonator, bias line, branch coupler, RF amplifier, measurement line, microstrip antenna are all designed with microstrip circuits and packaged in the box.

[0005] Specifically, the circuit of the mixer experiment is as follows: the Out interface of the mixer module is connected to the RFIN interface of the spectrum analyzer, the RF interface of the mixer module is connected to the Fou interface of the first voltage-controlled oscillator through an attenuator, the L0 interface of the RF interface of the mixer module is connected to the Fout interface of the second voltage-controlled oscillator, and the first voltage-controlled oscillator and the second voltage-controlled oscillator are powered by a DC regulated power supply.

[0006] Specifically, the circuit of the circulator experiment is as follows: the circulator is connected to the spectrum analyzer and the load respectively, the TG interface and RF IN interface of the spectrum analyzer are connected to the P1 interface and P2 interface of the circulator respectively, and the P3 interface of the circulator is connected to the load.

[0007] Specifically, the circuit of the directional coupler experiment is as follows: the circulator is connected to the spectrum analyzer and the load respectively, the TG interface and RF IN interface of the spectrum analyzer are connected to the P1 interface and P2 interface of the circulator respectively, and the P3 interface of the circulator is connected to the load.

[0008] Specifically, the circuit of the power divider experiment is as follows: the P1 interface and the P2 interface of the power divider are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the P3 interface of the power divider is connected to the load.

[0009] Specifically, the circuit of the hybrid circulator experiment is as follows: the P1 interface and the P2 interface of the hybrid circulator are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the P3 and P4 interfaces of the hybrid circulator are each connected to a load.

[0010] Specifically, the circuit of the PIN switch experiment is as follows: the P1 and P2 interfaces of the PIN switch are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, the P3 interface of the PIN switch is connected to the load, and the P4 and P5 interfaces of the PIN switch are connected to the DC regulated power supply.

[0011] Specifically, the circuit of the PIN modulator experiment is as follows: the P1 interface of the PIN modulator is connected to the digital oscilloscope through a coaxial detector, the P2 interface of the PIN modulator is connected to the RF interface of the first voltage-controlled oscillator, and the P3 interface of the PIN modulator is connected to the signal generator.

[0012] Specifically, the circuit of the filter experiment is as follows: the P1 interface and the P2 interface of the filter are connected to the TG and RF IN interfaces of the spectrum analyzer respectively.

[0013] Specifically, the circuit of the branch coupler experiment is as follows: the P1 interface and the P2 interface of the branch coupler are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the P3 and P4 interfaces of the branch coupler are connected to a load respectively.

[0014] Specifically, the circuit of the RF amplifier experiment is as follows: the Input interface and Output interface of the RF amplifier are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the VCC interface of the RF amplifier is connected to a DC regulated power supply.

[0015] Specifically, the circuit of the microstrip antenna experiment is as follows: the microstrip antenna includes a transmitting antenna and a receiving antenna, the transmitting end is: the transmitting antenna is connected to a voltage-controlled oscillator, and the voltage-controlled oscillator is also connected to a DC regulated power supply; the receiving end is: the receiving antenna is connected to a spectrum analyzer.

[0016] Specifically, the circuit of the RF front-end transmitter / receiver is as follows: the RF front-end transmitter / receiver includes a RF front-end transmitter and a RF front-end receiver, the transmitting end is: the P1 interface of the PIN modulator is connected to the P1 interface of the directional coupler, the P2 interface of the PIN modulator is connected to the RF interface of the first voltage-controlled oscillator, the Vbias interface of the PIN modulator is connected to the square wave interface of the function signal generator, the P2 interface of the directional coupler is connected to the low-pass filter, the P3 interface of the directional coupler is connected to the spectrum analyzer, and the P4 interface of the directional coupler is connected to the load; the receiving end is: the OUT interface of the amplifier is connected to the RF interface of the mixer, the OUT interface of the mixer is connected to the IN interface of the detector, the OUT interface of the detector is connected to the digital oscilloscope, and the LO interface of the mixer is connected to the second voltage-controlled oscillator.

[0017] Specifically, the output microstrip line of the voltage-controlled oscillator has a width of 3.8mm and a length of 32mm; the microstrip width of the mixer is 3.8mm; the microstrip width of the circulator is 3.8mm; the microstrip coupling line scale of the directional coupler is 3.8mm and the length is 33.5mm; the microstrip main line is 88mm long, 3.8mm wide, and has a coupling degree of 10dB; the microstrip width of the measurement line is 3.8mm and the length is 220mm.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) The system has a sophisticated structure and can implement up to 20 basic RF experiments with as few RF components as possible, greatly meeting the teaching and learning needs of teachers and students.

[0020] (2) The system is powerful. The RF components in the system are packaged into modules of uniform form. All modules are designed with microstrip circuits. The structure of all microstrip circuits can be observed at a glance. Through practical training, students can gain more knowledge about the working principles, simulation analysis, test instruments and measurement skills of RF systems in the 3GHz frequency band.

[0021] (3) The modular design of the system enables the entire system to be accommodated in a dedicated instrument box (one module, one hole), with a compact structure and easy storage and transportation.

[0022] (4) The system is mainly used in school education, experimental courses in RF-related majors such as electronics and radio. The relevant knowledge can be applied to wireless communication systems, radar systems, navigation systems, sensors, electronic warfare systems, medical systems, space research, wireless power transmission and other fields. It has a wide range of applications and strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1( a ) is a diagram showing an experimental connection of a voltage-controlled oscillator according to an embodiment of the present invention.

[0024] FIG1( b ) is a PCB design diagram of a voltage-controlled oscillator according to an embodiment of the present invention.

[0025] FIG2( a ) is a diagram showing the experimental connection of a mixer according to an embodiment of the present invention.

[0026] FIG2( b ) is a PCB design diagram of a mixer according to an embodiment of the present invention.

[0027] FIG3( a ) is a diagram of a circulator experiment of an embodiment of the present invention.

[0028] FIG3( b ) is a PCB design diagram of a circulator according to an embodiment of the present invention.

[0029] FIG4( a ) is a connection diagram of a directional coupler experiment according to an embodiment of the present invention.

[0030] FIG4( b ) is a PCB design diagram of a directional coupler according to an embodiment of the present invention.

[0031] Figure 5 This is a diagram of an attenuator experiment (standard parts) of an embodiment of the present utility model.

[0032] FIG6 (a) is an experimental connection diagram of a power divider according to an embodiment of the present invention.

[0033] FIG6( b ) is a PCB design diagram of a power divider according to an embodiment of the present invention.

[0034] FIG7( a ) is a diagram of the experimental connection of the hybrid circulator according to an embodiment of the present invention.

[0035] FIG7( b ) is a PCB design diagram of a hybrid circulator according to an embodiment of the present invention.

[0036] FIG8( a ) is a PIN switch experimental connection diagram of an embodiment of the present utility model.

[0037] FIG8( b ) is a PCB design diagram of a PIN switch according to an embodiment of the present invention.

[0038] FIG9( a ) is a diagram showing an experimental connection of a PIN modulator according to an embodiment of the present invention.

[0039] FIG9( b ) is a PCB design diagram of a PIN modulator according to an embodiment of the present invention.

[0040] Figure 10 This is a connection diagram of a coaxial detector (standard component) experiment according to an embodiment of the present utility model.

[0041] FIG11( a ) is a filter experimental connection diagram of an embodiment of the present invention.

[0042] FIG11( b ) is a PCB design diagram of a high-pass filter according to an embodiment of the present invention.

[0043] FIG11( c ) is a PCB design diagram of a low-pass filter according to an embodiment of the present invention.

[0044] FIG11( d ) is a PCB design diagram of a bandpass filter according to an embodiment of the present invention.

[0045] FIG11( e ) is a PCB design diagram of a band-stop filter according to an embodiment of the present invention.

[0046] FIG12( a ) is a diagram showing the experimental connection of a circular resonator according to an embodiment of the present invention.

[0047] FIG12( b ) is a PCB design diagram of a circular resonator according to an embodiment of the present invention.

[0048] FIG13( a ) is a bias line experimental connection diagram of an embodiment of the present invention.

[0049] FIG13( b ) is a PCB design diagram of a bias line according to an embodiment of the present invention.

[0050] FIG14( a ) is an experimental connection diagram of a branch coupler according to an embodiment of the present invention.

[0051] FIG14( b ) is a PCB design diagram of a branch coupler according to an embodiment of the present invention.

[0052] FIG15( a ) is a diagram showing an experimental connection of a radio frequency amplifier according to an embodiment of the present invention.

[0053] FIG15( b ) is a PCB design diagram of the radio frequency amplifier according to an embodiment of the present invention.

[0054] FIG16( a ) is a diagram showing the experimental connection of a measuring line according to an embodiment of the present invention.

[0055] FIG16( b ) is a PCB design diagram of a measurement line according to an embodiment of the present invention.

[0056] FIG17( a ) is a diagram showing the experimental connection of a microstrip antenna according to an embodiment of the present invention.

[0057] FIG17( b ) is a PCB design diagram of a microstrip antenna according to an embodiment of the present invention.

[0058] Figure 18 This is an experimental diagram of the radio frequency front-end transmitter / receiver of an embodiment of the present utility model.

[0059] Figure 19 It is a box structure design drawing of the packaging module of an embodiment of the present utility model. DETAILED DESCRIPTION

[0060] 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.

[0061] The RF teaching and training system provided in this embodiment is specifically the AT-RF3030 RF teaching and training system, which is a dedicated device for RF teaching and training. It is designed to enable students to gain more rational and perceptual knowledge about the basic structure, working principle, simulation analysis, test instruments and measurement skills of RF systems through experiments, truly master basic concepts such as time domain and frequency domain, transmission lines, radio wave propagation, antennas, waveguides, RF modules, and RF communications, and learn to use important RF test instruments.

[0062] The AT-RF3030 RF teaching and training system provided in this embodiment includes 29 components, including two voltage-controlled oscillators, one mixer, one circulator, one directional coupler, one power divider, one hybrid circulator, one PIN switch, one PIN modulator, filters (one low-pass filter, one high-pass filter, one band-pass filter, and one band-stop filter), one bias line, one circular resonator, one branch coupler, two RF amplifiers, two attenuators, one coaxial detector, two microstrip antennas (one transmitting antenna and one receiving antenna), one measurement cable, and five calibration components. The system also includes accessories such as adapters, connectors, power cables, and RF cables, enabling 20 experiments. The relevant technical parameters are shown in Table 1.

[0063] Among them, voltage-controlled oscillators, mixers, circulators, directional couplers, power dividers, hybrid circulators, PIN switches, PIN modulators, low-pass filters, high-pass filters, band-pass filters, band-stop filters, bias lines, circular resonators, bias lines, branch couplers, RF amplifiers, measurement lines, and microstrip antennas are packaged in the box, and the modules packaged in the box all adopt microstrip circuit design. The main structure of the box is as follows: Figure 19The box is a rectangular parallelepiped structure that runs vertically through the box. Two sets of clips are located on the front and rear walls, one at a corresponding location on each side. The clips have U-shaped openings, each facing each other, and are used to secure the modules placed within the box. The box includes an upper cover made of transparent plexiglass.

[0064] Table 1 System module composition and related technical parameters

[0065] Serial number Module model and name Main indicators quantity 1 AT-RF3030-1 VCO Voltage Controlled Oscillator Frequency range F = 1300 ~ 2350MHz; adjustable voltage 1 ~ 20V; Po ≥ 5dBm; second harmonic: ≤ -10dB; spurious (far side): > 25dB, connector SMA-female 2 2 AT-RF3030-2 mixer RF / LO: Frequency range F = 200 ~ 3000MHz; Intermediate frequency IF = 50 ~ 1000MHz; Input amplitude RF ≤ -27dBm, Lo local oscillator ≥ 5dBm, Mixing loss L ≤ 12dB, Leakage (LO-IF) ≤ 20dB; Connector SMA-female 1 3 AT-RF3030-3 Circulator Frequency range F=1800~2200MHz; Transmission insertion loss L≤3dB; Port isolation I≥13dB; Connector SMA-female. 1 4 AT-RF3030-4 Directional Coupler Frequency range F = 1600MHz ~ 2400MHz; Transmission loss I ≤ 1.2dB; Coupling degree C = (10 ± 2)dB; Isolation I ≥ 20dB; Connector SMA-female. 1 5 AT-RF3030-8 Power Divider Frequency range F=1000~2000MHz; Transmission loss I≤-4.0dB; Isolation ≥10dB; Connector SMA-female. 1 6 AT-RF3030-9 Mixing Ring Frequency range F=1750~2350MHz; Transmission loss I≤5.0dB; Isolation I≥15dB; Connector SMA-female. 1 7 AT-RF3030-10 PIN switch Frequency range F=750~2500MHz; conduction loss L≤5dB; off-state attenuation I≥12dB; connector SMA-female. 1 8 AT-RF3030-11 PIN modulator The modulation waveform is stable and clear. Connector: SMA-female. 1 9 AT-RF3030-12 low-pass filter Cut-off frequency F = 2.1 GHz (typical); insertion loss L ≤ 2 dB; connector SMA- female. 1 10 AT-RF3030-13 Bandpass Filter Frequency range F = 1.8GHz ~ 2GHz (typical); In-band insertion loss L ≤ 4dB; Connector SMA-female. 1 11 AT-RF3030-14 Band-Rejection Filter Frequency range F = 1.5GHz ~ 2.2GHz (typical); stopband loss L ≥ 30dB; connector SMA-female. 1 12 AT-RF3030-15 High-Pass Filter Starting frequency F = 1.8 GHz (typical); in-band loss L ≤ 2 dB; connector SMA-female. 1 13 AT-RF3030-16 Circular Resonant Cavity Center frequency f0 = 2 GHz (typical), Q value greater than 30; connector SMA-female. 1 14 AT-RF3030-19 bias line Bias line 3 (dish 410 MHz, bias line 2: square 389 MHz, bias line 1: sector 556 MHz) frequencies are typical values; connector: SMA- female. 1 15 AT-RF3030-20 Branch Coupler Frequency range Fo = 1900 ~ 2300 MHz; Transmission loss L ≤ 3dB; Port coupling C ≤ 6dB; Isolation I ≥ 12dB; Connector SMA-female. 1 16 AT-RF3030-21 RF Amplifier Frequency range F=50~2600MHz; Gain range ≥10dB; Maximum output: 10dBm; Connector SMA-female. 2 17 AT-RF3030-22 Antenna Frequency range F = 1300-2400MHz. Transmit and receive experimental signals are clear and stable. Connector: SMA-female. 2 18 AT-RF3030-23 measuring cable Moving distance ≥170mm, residual standing wave ratio ≤1.05; connector SMA-female. 1 19 AT-RF3030-24 Coaxial Detector Frequency range F=0.5~3GHz, connector SMA-JK, sensitivity ≥100mV / mW (RF power 1 milliwatt); waveform output is stable and clear; connector SMA-female. 1

[0066] Experiment 1 Voltage Controlled Oscillator (VCO)

[0067] Figures 1(a) and 1(b) show the experimental diagrams and PCB design of the voltage-controlled oscillator (VCO) provided in this embodiment. The VCO is connected to a spectrum analyzer and a DC regulated power supply, respectively. The VCO microstrip PCB layout shows the VCO: V585ME66-LF, with an output microstrip line width of 3.8 mm and a length of 32 mm.

[0068] Experiment 2 Mixer

[0069] As shown in Figures 2(a) and 2(b), the experimental diagrams and PCB design of the voltage-controlled oscillator provided in this embodiment show that the Out port of the mixer module is connected to the RF IN port of the spectrum analyzer. The RF port of the mixer module is connected to the Fou port of the first voltage-controlled oscillator via an attenuator. The L0 port of the RF port of the mixer module is connected to the Fout port of the second voltage-controlled oscillator. The first and second voltage-controlled oscillators are powered by a DC regulated power supply. In the mixer PCB diagram, C1, C2, and C3 are (1206CG)204-K-500-NT, with a microstrip width of 3.8 mm.

[0070] Experiment 3 Circulator

[0071] Figures 3(a) and 3(b) show the experimental diagrams and PCB design of the circulator provided in this embodiment. The circulator is connected to a spectrum analyzer and a load. The TG and RF IN interfaces of the spectrum analyzer (spectrum analyzer) are connected to the circulator's P1 and P2 interfaces, respectively. The circulator's P3 interface is connected to the load. The circulator PCB diagram shows a microstrip width of 3.8 mm, a U rating of 1.8-2.2 GHz, and a DH102FC.

[0072] Experiment 4 Directional Coupler

[0073] Figures 4(a) and 4(b) show the experimental diagrams and PCB design for the circulator provided in this embodiment. The circulator is connected to a spectrum analyzer and a load, respectively. The spectrum analyzer's TG and RF IN interfaces are connected to the circulator's P1 and P2 interfaces, respectively. The circulator's P3 interface is connected to the load. The directional coupler PCB diagram shows a microstrip coupling line with a 3.8mm scale and a length of 33.5mm. The microstrip main line is 88mm long and 3.8mm wide, with a coupling factor of 10dB.

[0074] Experiment 5 Attenuator

[0075] like Figure 5 As shown in FIG. 1 , it is an experimental diagram of the attenuator provided in this embodiment, where both ends of the attenuator are connected to the OUT and IN interfaces of the spectrum analyzer respectively.

[0076] Experiment 6 Power Divider

[0077] As shown in Figure 6 (a) and (b), which are the experimental diagrams and PCB design diagrams of the power divider provided in this embodiment, the P1 interface and P2 interface of the power divider are respectively connected to the TG and RF IN interfaces of the spectrum analyzer, and the P3 interface of the power divider is connected to the load.

[0078] Experiment 7: Hybrid Circulator

[0079] As shown in Figure 7 (a) and (b), the experimental diagram and PCB design diagram of the hybrid circulator provided in this embodiment are shown. The P1 and P2 interfaces of the hybrid circulator are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the P3 and P4 interfaces of the hybrid circulator are connected to a 50 load.

[0080] Experiment 8 PIN Switch

[0081] Figures 8(a) and 8(b) show the experimental diagrams and PCB design for the PINRF switch provided in this embodiment. The P1 and P2 interfaces of the PIN switch (module) are connected to the TG and RF IN interfaces of the spectrum analyzer, respectively. The P3 interface of the PIN switch (module) is connected to the load, and the P4 and P5 interfaces of the PIN switch (module) are connected to a DC regulated power supply. The PIN switch PCB layout includes: R1 / R2: 470Ω ±5% resistors, C1-C6: 204-K-500-NT capacitors, and a HSMP-3814 common cathode diode.

[0082] Experiment 9 PIN Modulator

[0083] Figures 9(a) and 9(b) show the experimental diagrams and PCB design for the PIN modulator of this embodiment. The P1 interface of the PIN modulator is connected to a digital oscilloscope via a coaxial detector, the P2 interface of the PIN modulator is connected to the RF interface of the first voltage-controlled oscillator, and the P3 interface of the PIN modulator is connected to a signal generator. The PIN modulator PCB layout includes resistor R (390Ω±5%), C1 / C2 (101-J-500-NT), and common cathode diode U (HSMP-3814).

[0084] Experiment 10 Coaxial Detector

[0085] like Figure 10 The following is a coaxial detector experimental diagram and PCB design diagram provided in this embodiment. It is the same as Figure 9 (a), except that the VCC voltage of the voltage-controlled oscillator is 12V and the Vt voltage is 9.8V.

[0086] Experiment 11 Filters (Low-pass filter LPF, High-pass filter HPF, Band-pass filter BPF, Band-stop filter BSF)

[0087] As shown in Figure 11 (a), (b), (c), (d), and (e), the filter experiment diagram and the corresponding PCB design diagram provided in this embodiment are shown. The two interfaces (the modules are symmetrically designed and can be connected arbitrarily) of the filter (containing four modules for four experiments) are connected to the TG and RF IN interfaces of the spectrum analyzer.

[0088] Experiment 12 Circular Resonator

[0089] Figures 12(a) and 12(b) show the experimental diagrams and PCB design of the circular resonator provided in this embodiment. The P1 and P2 interfaces of the circular resonator are connected to the TG and RF IN interfaces of the spectrum analyzer, respectively.

[0090] Experiment 13 Bias Line (Fan-Shaped)

[0091] Figures 13(a) and 13(b) show the bias line experimental diagram and PCB design diagram provided in this embodiment. The two interfaces of the bias line are connected to the TG and RF IN interfaces of the spectrum analyzer.

[0092] Experiment 14 Branch Coupler

[0093] As shown in Figure 14 (a) and (b), which are the experimental diagrams and PCB design diagrams of the branch coupler provided in this embodiment, the P1 interface and P2 interface of the branch coupler are respectively connected to the TG and RF IN interfaces of the spectrum analyzer, and the P3 and P4 interfaces of the branch coupler are each connected to a load.

[0094] Experiment 15 RF Amplifier

[0095] Figures 15(a) and 15(b) show the experimental diagrams and PCB design for the RF amplifier of this embodiment. The RF amplifier's Input and Output interfaces are connected to the spectrum analyzer's TG and RF IN interfaces, respectively. The RF amplifier's VCC interface is connected to a DC regulated power supply. The RF amplifier's microstrip PCB layout includes capacitor C1 (102J-500-NT), capacitors C2 / C3 (204-K-500-NT), amplifier U (ERA-3SM+), inductor L (100nH), and resistor R (499Ω ±1%).

[0096] Experiment 16 Measuring Lines

[0097] As shown in FIG16 (a) and (b), which are the measurement line experimental diagram and PCB design diagram provided in this embodiment, the voltage-controlled oscillator and the load are connected through the measurement line, and the measurement line is also connected to the spectrum analyzer.

[0098] The connection diagrams for the two experiments, Experiment 17 with matched load and Experiment 18 with mismatched load, are the same as those in Figure 16(a).

[0099] Experiment 19 Microstrip Antenna

[0100] Figures 17(a) and 17(b) show the experimental diagrams and PCB design for the microstrip antenna provided in this embodiment. The microstrip antenna includes a transmitting antenna and a receiving antenna. At the transmitting end, the transmitting antenna is connected to a voltage-controlled oscillator, which is also connected to a DC regulated power supply. At the receiving end, the receiving antenna is connected to a spectrum analyzer. The measurement line microstrip PCB diagram shows a width of 3.8 mm and a length of 220 mm.

[0101] Experiment 20 RF front-end transmitter / receiver.

[0102] like Figure 18 As shown, it is an experimental diagram of the RF front-end transmitter / receiver provided in this embodiment. The RF front-end transmitter / receiver includes an RF front-end transmitter and an RF front-end receiver. The transmitting end is: the P1 interface of the PIN modulator is connected to the P1 interface of the directional coupler, the P2 interface of the PIN modulator is connected to the RF interface of the first voltage-controlled oscillator, the Vbias interface of the PIN modulator is connected to the square wave interface of the function signal generator, the P2 interface of the directional coupler is connected to the low-pass filter, the P3 interface of the directional coupler is connected to the spectrum analyzer, and the P4 interface of the directional coupler is connected to the load; the receiving end is: the OUT interface of the amplifier is connected to the RF interface of the mixer, the OUT interface of the mixer is connected to the IN interface of the detector, the OUT interface of the detector is connected to the digital oscilloscope, and the LO interface of the mixer is connected to the second voltage-controlled oscillator.

[0103] This embodiment targets the most important fields such as RF communication, sensing, and signal processing, which contain a lot of important information that is inconvenient to represent or difficult to measure in the time domain. It uses a spectrum analyzer with high sensitivity and wide dynamic range to measure low-level amplitude-modulated, frequency-modulated, and pulse-modulated RF signals. It can also measure carrier frequency, modulation frequency, modulation level, and modulation distortion. It can also easily detect characteristics such as frequency conversion loss, isolation, and distortion of frequency conversion devices. The RF teaching and training device of this embodiment is designed to enable students to gain more rational and perceptual understanding of the basic structure, operating principles, simulation analysis, test instruments, and measurement skills of RF systems through experiments, truly master basic concepts such as time domain and frequency domain, transmission lines, radio wave propagation, antennas, waveguides, RF modules, and RF communication, and learn to use important RF test instruments.

[0104] The modules in the RF teaching and training device of this embodiment all use a microstrip circuit design (microwave plate, plate thickness 1.6 mm, dielectric constant 2.4). The top cover is made of transparent organic glass, which allows the structure of the entire microstrip circuit to be clearly observed at a glance, better helping students understand and master the basic structure and working principles of the RF system.

[0105] The radio frequency training system of this embodiment is equipped with a dedicated instrument box (one module, one hole position) for easy storage and transportation.

[0106] 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 radio frequency teaching and training system, characterized in that: The system includes: 2 voltage-controlled oscillators, 1 mixer, 1 circulator, 1 directional coupler, 1 power divider, 1 hybrid circulator, 1 PIN switch, 1 PIN modulator, 1 low-pass filter, 1 high-pass filter, 1 band-pass filter, 1 band-stop filter, 1 bias line, 1 circular resonator, 1 branch coupler, 2 radio frequency amplifiers, 2 attenuators, 1 coaxial detector, 2 microstrip antennas, 1 measurement line, and 5 calibration pieces, which are used to realize 20 experiments, including voltage-controlled oscillator experiments, mixer experiments, circulator experiments, directional coupler experiments, attenuator experiments, power divider experiments, Distributor experiment, hybrid circulator experiment, PIN switch experiment, PIN modulator experiment, coaxial detector experiment, filter experiment, circular resonator experiment, branch coupler experiment, RF amplifier experiment, measurement line experiment, microstrip antenna experiment, RF front-end transmitter / receiver experiment; voltage-controlled oscillator, mixer, circulator, directional coupler, power divider, hybrid circulator, PIN switch, PIN modulator, low-pass filter, high-pass filter, band-pass filter, band-stop filter, bias line, circular resonator, bias line, branch coupler, RF amplifier, measurement line, microstrip antenna are all designed with microstrip circuits and packaged in the box; The circuit of the mixer experiment is as follows: the Out interface of the mixer module is connected to the RF IN interface of the spectrum analyzer, the RF interface of the mixer module is connected to the Fout interface of the first voltage-controlled oscillator through an attenuator, the L0 interface of the RF interface of the mixer module is connected to the Fout interface of the second voltage-controlled oscillator, and the first and second voltage-controlled oscillators are powered by a DC regulated power supply.

2. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the circulator experiment is as follows: the circulator is connected to the spectrum analyzer and the load respectively, the TG interface and RF IN interface of the spectrum analyzer are connected to the P1 interface and P2 interface of the circulator respectively, and the P3 interface of the circulator is connected to the load.

3. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the directional coupler experiment is as follows: the circulator is connected to the spectrum analyzer and the load respectively, the TG interface and RF IN interface of the spectrum analyzer are connected to the P1 interface and P2 interface of the circulator respectively, and the P3 interface of the circulator is connected to the load.

4. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the power divider experiment is as follows: the P1 interface and the P2 interface of the power divider are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the P3 interface of the power divider is connected to the load.

5. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the hybrid circulator experiment is as follows: the P1 interface and P2 interface of the hybrid circulator are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the P3 and P4 interfaces of the hybrid circulator are each connected to a load.

6. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the PIN switch experiment is as follows: the P1 and P2 interfaces of the PIN switch are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, the P3 interface of the PIN switch is connected to the load, and the P4 and P5 interfaces of the PIN switch are connected to the DC regulated power supply.

7. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the PIN modulator experiment is as follows: the P1 interface of the PIN modulator is connected to the digital oscilloscope through a coaxial detector, the P2 interface of the PIN modulator is connected to the RF interface of the first voltage-controlled oscillator, and the P3 interface of the PIN modulator is connected to the signal generator.

8. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the filter experiment is as follows: the P1 interface and the P2 interface of the filter are connected to the TG and RF IN interfaces of the spectrum analyzer respectively.

9. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the branch coupler experiment is as follows: the P1 interface and the P2 interface of the branch coupler are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the P3 and P4 interfaces of the branch coupler are connected to a load respectively.

10. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the RF amplifier experiment is as follows: the Input interface and Output interface of the RF amplifier are connected to the TG and RF IN interfaces of the spectrum analyzer respectively, and the VCC interface of the RF amplifier is connected to a DC regulated power supply.

11. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the microstrip antenna experiment is as follows: the microstrip antenna includes a transmitting antenna and a receiving antenna, the transmitting end is: the transmitting antenna is connected to a voltage-controlled oscillator, and the voltage-controlled oscillator is also connected to a DC regulated power supply; the receiving end is: the receiving antenna is connected to a spectrum analyzer.

12. The radio frequency teaching and training system according to claim 1, characterized in that: The circuit of the RF front-end transmitter / receiver is as follows: the RF front-end transmitter / receiver includes a RF front-end transmitter and a RF front-end receiver. At the transmitting end, the P1 interface of the PIN modulator is connected to the P1 interface of the directional coupler, the P2 interface of the PIN modulator is connected to the RF interface of the first voltage-controlled oscillator, the Vbias interface of the PIN modulator is connected to the square wave interface of the function signal generator, the P2 interface of the directional coupler is connected to the low-pass filter, the P3 interface of the directional coupler is connected to the spectrum analyzer, and the P4 interface of the directional coupler is connected to the load; at the receiving end, the OUT interface of the amplifier is connected to the RF interface of the mixer, the OUT interface of the mixer is connected to the IN interface of the detector, the OUT interface of the detector is connected to the digital oscilloscope, and the LO interface of the mixer is connected to the second voltage-controlled oscillator.

13. The radio frequency teaching and training system according to claim 1, characterized in that: The output microstrip line of the voltage-controlled oscillator has a width of 3.8mm and a length of 32mm; the microstrip width of the mixer is 3.8mm; the microstrip width of the circulator is 3.8mm; the microstrip coupling line scale of the directional coupler is 3.8mm and the length is 33.5mm; the microstrip main line is 88mm long, 3.8mm wide, and has a coupling degree of 10dB; the microstrip width of the measurement line is 3.8mm and the length is 220mm.

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