Ultra-wide spectrum electromagnetic shielding effectiveness measurement device and method

Abstract

The present invention discloses an ultra-wide spectrum electromagnetic shielding effectiveness measurement device and method, which relate to the technical field of electromagnetic shielding effectiveness measurement. The device comprises a shielding body to be measured, wherein an ultra-wide spectrum transmitting module is arranged on the outside of the shielding body to be measured, and the ultra-wide spectrum transmitting module is used to transmit ultra-wide spectrum electromagnetic waves; an ultra-wide spectrum receiving module is arranged on the inside of the shielding body to be measured, and the ultra-wide spectrum receiving module is used to receive ultra-wide spectrum electromagnetic waves, collect and process data, and display data. The ultra-wide spectrum transmitting module comprises an ultra-wide spectrum signal source, a cable, and a transmitting antenna, and the ultra-wide spectrum signal source is electrically connected to the transmitting antenna via the cable. In the present invention, through the design of the shielding body to be measured, the ultra-wide spectrum transmitting module, and the ultra-wide spectrum receiving module, the ultra-wide spectrum electromagnetic shielding effectiveness measurement device is small in size, the ultra-wide spectrum receiving module is placed in the shielding body to be measured, the production cost is low, and the device can be widely used.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding effectiveness measurement, and in particular to an ultra-wide spectrum electromagnetic shielding effectiveness measurement device and method. Background Art

[0002] Ultra-wideband high-power electromagnetic signals have a very wide frequency range, with energy distribution from 100MHz to 1GHz. They are highly penetrating and destructive. To combat high-power, ultra-wideband electromagnetic energy, an effective method is to shield electronic equipment. When conducting relevant analysis and design, it is important to understand the shielding effectiveness of the electromagnetic shielding system under consideration against ultra-wideband signals. The ultra-wideband electromagnetic shielding effectiveness of a shield can be measured by referring to the electromagnetic shielding effectiveness measurement methods in GB / T12190 and GJB5792.

[0003] Ultra-wideband signals are pulsed time-domain signals and cannot be measured using spectrum analyzers or continuous wave signal detection methods. Instead, they are typically measured using digital oscilloscopes with very wide analog bandwidths and very high digital sampling frequencies. Wide-bandwidth digital oscilloscopes are very expensive, and some smaller shields cannot accommodate oscilloscopes. Without the ability to create holes in small shields, measuring their ultra-wideband electromagnetic shielding effectiveness is difficult. Therefore, we propose an ultra-wideband electromagnetic shielding effectiveness measurement device and method. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an ultra-wide spectrum electromagnetic shielding effectiveness measurement device and method.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An ultra-wide spectrum electromagnetic shielding effectiveness measuring device comprises a shielding body to be measured, an ultra-wide spectrum transmitting module is arranged outside the shielding body to be measured, and the ultra-wide spectrum transmitting module is used to transmit ultra-wide spectrum electromagnetic waves;

[0007] An ultra-wide spectrum receiving module is provided inside the shielding body to be tested, and the ultra-wide spectrum receiving module is used for receiving ultra-wide spectrum electromagnetic waves, collecting and processing data, and displaying data.

[0008] Preferably, the ultra-wide spectrum transmission module includes an ultra-wide spectrum signal source, a cable and a transmission antenna, and the ultra-wide spectrum signal source is electrically connected to the transmission antenna via the cable.

[0009] Preferably, the ultra-wide spectrum receiving module includes a receiving antenna, an impedance converter, a programmable attenuator, a signal amplifier, a peak detector, a comparator, a single-chip computer system and a display, wherein the receiving antenna and the programmable attenuator are electrically connected to the impedance converter, the programmable attenuator and the peak detector are electrically connected to the signal amplifier, the peak detector is electrically connected to the single-chip computer system, the display is electrically connected to the single-chip computer system via a serial communication port, the programmable attenuator is electrically connected to the single-chip computer system via another serial communication port, and the signal amplifier is electrically connected to the single-chip computer system via the comparator;

[0010] The receiving antenna is an integrated receiving antenna.

[0011] Preferably, the ultra-wide spectrum receiving module further comprises a metal shielding box, and the impedance converter, programmable attenuator, signal amplifier, peak detector, comparator, single chip microcomputer system and display are all packaged in the metal shielding box.

[0012] Preferably, an opening is formed on the outer wall of the metal shielding box, and a light-transmitting shielding film is installed at the opening of the metal shielding box, and the light-transmitting shielding film is used to see through the content displayed on the display.

[0013] A method for measuring the effectiveness of ultra-wide spectrum electromagnetic shielding is provided. The method is implemented based on an ultra-wide spectrum electromagnetic shielding effectiveness measuring device and comprises the following steps:

[0014] S1. Adjust the relative distance, direction and antenna polarization between the ultra-wide spectrum transmitting module and the ultra-wide spectrum receiving module;

[0015] S2. Start the ultra-wide spectrum receiving module and let it wait for a while, and then seal the shielded body under test.

[0016] S3, enabling the ultra-wide spectrum transmitting module to transmit ultra-wide spectrum electromagnetic waves of a certain period;

[0017] S4. The ultra-wide spectrum receiving module controls the attenuation value of its programmable attenuator to be set from large to small, and respectively receives the ultra-wide spectrum electromagnetic waves attenuated by the shielding body under test until the ultra-wide spectrum signal can be stably received. The ultra-wide spectrum receiving module collects the peak value and period of the ultra-wide spectrum signal;

[0018] If the sampled period is the same as that of the transmitted ultra-wide spectrum signal, the measurement data is considered normal. The peak value collected is multiplied by the attenuation factor set by the programmable attenuator to obtain the shielding peak value of the ultra-wide spectrum signal after shielding and attenuation by the measured shielding body. The shielding peak value and period of the ultra-wide spectrum signal are displayed on the display.

[0019] If the programmable attenuator has reached its minimum value, that is, the attenuation value is 0dB, and the ultra-wide spectrum signal cannot be stably received or the measured period is significantly different from the period of the transmitted ultra-wide spectrum signal, it is considered that the ultra-wide spectrum signal is less than the detection limit of the ultra-wide spectrum receiving module after being attenuated by the measured shield, and the display shows that it is below the detection limit;

[0020] S5. Stop the ultra-wide spectrum electromagnetic wave transmission of the ultra-wide spectrum transmitting module, and the ultra-wide spectrum receiving module automatically stops data collection and keeps the previous display content;

[0021] S6. Remove the shielding body to be tested and read the peak value and period on the display in the ultra-wide spectrum receiving module;

[0022] Keeping the relative distance, direction and polarization between the ultra-wide spectrum transmitting module and the ultra-wide spectrum receiving module unchanged, and the transmitting power of the ultra-wide spectrum transmitting module unchanged, repeat the above process, measure the peak value of the ultra-wide spectrum signal without shielding attenuation by the measured shielding body, and obtain the reference peak value of the ultra-wide spectrum signal;

[0023] S7, stopping the ultra-wide spectrum electromagnetic wave emission of the ultra-wide spectrum transmitting module, dividing the ultra-wide spectrum reference peak value by the shielding peak value after the ultra-wide spectrum signal is shielded and attenuated by the shield under test, to obtain the ultra-wide spectrum shielding effectiveness of the shield under test, and taking the logarithm to obtain the decibel number of the ultra-wide spectrum shielding effectiveness;

[0024] If the shielding peak is less than the detection limit, the ultra-wideband shielding effectiveness is greater than or equal to the reference peak divided by the detection limit.

[0025] The beneficial effects of the present invention are:

[0026] 1. In the present invention, through the design of the shielding body to be measured, the ultra-wide spectrum transmitting module, and the ultra-wide spectrum receiving module, the ultra-wide spectrum electromagnetic shielding effectiveness measuring device is small in size, and the ultra-wide spectrum receiving module is placed in the shielding body to be measured. The production cost is low and it can be widely used.

[0027] 2. The present invention replaces the high-performance digital oscilloscope with a peak detection method to measure ultra-wide signals; the period of the ultra-wide spectrum signal is used to confirm the measurement data, thereby improving the reliability of the measurement data.

[0028] 3. The present invention utilizes a single chip computer system intelligent program-controlled attenuator to expand the dynamic measurement range and improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural block diagram of an ultra-wide spectrum electromagnetic shielding effectiveness measurement device of the present invention.

[0030] Figure 2 This is a structural block diagram of an ultra-wide spectrum transmission module of an ultra-wide spectrum electromagnetic shielding effectiveness measurement device of the present invention.

[0031] Figure 3 The present invention provides a circuit diagram of an ultra-wide spectrum signal source for an ultra-wide spectrum electromagnetic shielding effectiveness measuring device.

[0032] Figure 4 This is a structural block diagram of an ultra-wide spectrum receiving module of an ultra-wide spectrum electromagnetic shielding effectiveness measurement device of the present invention.

[0033] Figure 5 This is a circuit diagram of an impedance converter for an ultra-wide spectrum electromagnetic shielding effectiveness measuring device of the present invention.

[0034] Figure 6 The present invention provides a circuit diagram of a peak detector of an ultra-wide spectrum electromagnetic shielding effectiveness measuring device.

[0035] Figure 7 The present invention provides a circuit diagram of a comparator for measuring the effectiveness of ultra-wide spectrum electromagnetic shielding.

[0036] Figure 8 The present invention provides a circuit diagram of a single-chip computer system for an ultra-wide spectrum electromagnetic shielding effectiveness measuring device. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0038] Example 1, as attached Figure 1 As shown, an ultra-wide spectrum electromagnetic shielding effectiveness measuring device includes a shielding body to be measured, an ultra-wide spectrum transmitting module is arranged outside the shielding body to be measured, and the ultra-wide spectrum transmitting module is used to transmit ultra-wide spectrum electromagnetic waves;

[0039] An ultra-wide spectrum receiving module is arranged inside the shielding body to be tested, and the ultra-wide spectrum receiving module is used for receiving ultra-wide spectrum electromagnetic waves, data acquisition and processing, and data display.

[0040] As attached Figure 2 As shown, the ultra-wide spectrum transmission module includes an ultra-wide spectrum signal source, a cable and a transmission antenna, and the ultra-wide spectrum signal source is electrically connected to the transmission antenna through the cable.

[0041] In the above technical solution, as shown in the attached Figure 3 As shown, the ultra-wide spectrum signal source uses an avalanche transistor as a high-speed electronic switch to charge the energy storage capacitor in parallel and discharge it in series to generate a high-voltage ultra-wide spectrum electromagnetic energy signal. After the energy storage capacitor of the ultra-wide spectrum signal source is charged, it is triggered by a steep square wave with a peak value of 15V. The avalanche transistor is quickly turned on, causing the energy storage capacitor to discharge in series and output an ultra-wide spectrum signal.

[0042] It is worth mentioning that the transmitting antenna of ultra-wide spectrum electromagnetic waves adopts an electromagnetic-magnetic combination vibrator, and the radiation system is compact and has high radiation efficiency.

[0043] As attached Figure 4 As shown, the ultra-wide spectrum receiving module includes a receiving antenna, an impedance converter, a programmable attenuator, a signal amplifier, a peak detector, a comparator, a single-chip computer system and a display. The receiving antenna and the programmable attenuator are electrically connected to the impedance converter, the programmable attenuator and the peak detector are electrically connected to the signal amplifier, the peak detector is electrically connected to the single-chip computer system, the display is electrically connected to the single-chip computer system through the COM1 serial port (a serial communication port), the programmable attenuator is electrically connected to the single-chip computer system through the COM2 serial port (another serial communication port), and the signal amplifier is electrically connected to the single-chip computer system through the comparator.

[0044] The receiving antenna is an integrated receiving antenna.

[0045] It is worth mentioning that, as Figure 4 To the attached Figure 5 As shown, the impedance converter is realized by a MOS tube with high input impedance, which is matched with the monopole antenna. The monopole antenna that receives the ultra-wide spectrum electromagnetic signal is coupled to the gate of the MOS tube through capacitance. The ultra-wide spectrum signal is output from the source with low impedance to the programmable attenuator.

[0046] It is worth mentioning that, as Figure 4 As shown, the programmable attenuator is intelligently controlled by the single-chip microcomputer system, and measures from the maximum attenuation value to the minimum attenuation value, and is subsequently connected to the signal amplifier and then to the peak detector; the peak value of the ultra-wide spectrum signal output by the peak detector is collected by the single-chip microcomputer system;

[0047] The signal amplifier also outputs a signal to the comparator to generate a synchronization pulse for the microcontroller system to perform synchronous data acquisition and signal cycle time measurement.

[0048] It is worth mentioning that, as Figure 4 To the attached Figure 8 As shown, the single-chip microcomputer used is STM32F103C8T6; the single-chip microcomputer system controls the attenuation value of the programmable attenuator through the COM2 serial port (PA2 and PA3 ports). After the PA11 port receives the synchronous acquisition signal of the comparator, the PA1 port starts to acquire the peak value output by the peak detector. After the acquisition is completed, the PA0 port controls the internal holding capacitor of the peak detector to be cleared, and uses two adjacent synchronous pulses to trigger the timer to calculate the period of the ultra-wide spectrum signal. Finally, the acquired data and the period of the ultra-wide spectrum signal are displayed on the monitor through the COM1 serial port (PA9 and PA10 ports).

[0049] As attached Figure 4As shown, the ultra-wide spectrum receiving module also includes a metal shielding box, and the impedance converter, programmable attenuator, signal amplifier, peak detector, comparator, single-chip microcomputer system and display are all encapsulated in the metal shielding box to prevent the ultra-wide spectrum receiving module itself from being interfered by ultra-wide spectrum electromagnetic energy.

[0050] It is worth mentioning that the receiving antenna is directly installed on the outside of the metal shielding box. A small hole is opened on the outer wall of the metal shielding box. The cable of the receiving antenna is electrically connected to the impedance converter inside the metal shielding box through the small hole on the metal shielding box to complete the reception of ultra-wide spectrum electromagnetic signals.

[0051] As attached Figure 4 As shown, an opening is provided on the outer wall of the metal shielding box, and a light-transmitting shielding film is installed at the opening of the metal shielding box. The light-transmitting shielding film is used to see through the contents displayed on the display.

[0052] In the above technical solution, the metal shielding box that encapsulates the ultra-wide spectrum receiving module has an opening on the display side and is sealed with a light-transmitting shielding film to form a complete shielding body that can protect the ultra-wide spectrum receiving module. A battery is used inside the metal shielding box to power the internal devices.

[0053] Example 2, a method for measuring ultra-wide spectrum electromagnetic shielding effectiveness, which is based on the ultra-wide spectrum electromagnetic shielding effectiveness measuring device in Example 1, comprises the following steps:

[0054] S1. Adjust the relative distance, direction and antenna polarization between the ultra-wide spectrum transmitting module and the ultra-wide spectrum receiving module;

[0055] S2. Start the ultra-wide spectrum receiving module and let it wait for a while, and then seal the shielded body under test.

[0056] S3, enabling the ultra-wide spectrum transmitting module to transmit ultra-wide spectrum electromagnetic waves of a certain period;

[0057] S4. The ultra-wide spectrum receiving module controls the attenuation value of its programmable attenuator to be set from large to small, and respectively receives the ultra-wide spectrum electromagnetic waves attenuated by the shielding body under test until the ultra-wide spectrum signal can be stably received. The ultra-wide spectrum receiving module collects the peak value and period of the ultra-wide spectrum signal;

[0058] If the sampled period is the same as that of the transmitted ultra-wide spectrum signal, the measurement data is considered normal. The peak value collected is multiplied by the attenuation factor set by the programmable attenuator to obtain the shielding peak value of the ultra-wide spectrum signal after shielding and attenuation by the measured shielding body. The shielding peak value and period of the ultra-wide spectrum signal are displayed on the display.

[0059] If the programmable attenuator has reached its minimum value, that is, the attenuation value is 0dB, and the ultra-wide spectrum signal cannot be stably received or the measured period is significantly different from the period of the transmitted ultra-wide spectrum signal, it is considered that the ultra-wide spectrum signal is less than the detection limit of the ultra-wide spectrum receiving module after being shielded and attenuated by the measured shield, and the display shows that it is below the detection limit;

[0060] S5. Stop the ultra-wide spectrum electromagnetic wave transmission of the ultra-wide spectrum transmitting module, and the ultra-wide spectrum receiving module automatically stops data collection and keeps the previous display content;

[0061] S6. Remove the shielding body to be tested and read the peak value and period on the display in the ultra-wide spectrum receiving module;

[0062] Keeping the relative distance, direction and polarization between the ultra-wide spectrum transmitting module and the ultra-wide spectrum receiving module unchanged, and the transmitting power of the ultra-wide spectrum transmitting module unchanged, repeat the above process, measure the peak value of the ultra-wide spectrum signal without shielding and attenuation by the measured shield (multiplying the sampling peak value by the attenuation value of the programmable attenuator), and obtain the reference peak value of the ultra-wide spectrum signal;

[0063] S7, stopping the ultra-wide spectrum electromagnetic wave emission of the ultra-wide spectrum transmitting module, dividing the reference peak value of the ultra-wide spectrum signal by the shielding peak value of the ultra-wide spectrum signal after shielding and attenuation by the shield under test, to obtain the ultra-wide spectrum shielding effectiveness of the shield under test, and taking the logarithm to obtain the decibel number of the ultra-wide spectrum shielding effectiveness;

[0064] If the shielding peak is less than the detection limit, the ultra-wideband shielding effectiveness is greater than or equal to the reference peak divided by the detection limit.

[0065] Please refer to the above structure and process Figure 1-8 .

[0066] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. An ultra-wide spectrum electromagnetic shielding effectiveness measuring device, comprising a shielding body to be measured, characterized in that: An ultra-wide spectrum transmitting module is provided on the outside of the shielding body to be tested, and the ultra-wide spectrum transmitting module is used to transmit ultra-wide spectrum electromagnetic waves; An ultra-wide spectrum receiving module is provided inside the shielding body to be tested, and the ultra-wide spectrum receiving module is used to receive ultra-wide spectrum electromagnetic waves, collect and process data, and display data; The ultra-wide spectrum transmission module includes an ultra-wide spectrum signal source, a cable and a transmitting antenna, and the ultra-wide spectrum signal source is electrically connected to the transmitting antenna through the cable; The ultra-wide spectrum receiving module includes a receiving antenna, an impedance converter, a programmable attenuator, a signal amplifier, a peak detector, a comparator, a single-chip computer system and a display. The receiving antenna and the programmable attenuator are electrically connected to the impedance converter, the programmable attenuator and the peak detector are electrically connected to the signal amplifier, the peak detector is electrically connected to the single-chip computer system, the display is electrically connected to the single-chip computer system via a serial communication port, the programmable attenuator is electrically connected to the single-chip computer system via another serial communication port, and the signal amplifier is electrically connected to the single-chip computer system via the comparator. The receiving antenna is an integrated receiving antenna.

2. The ultra-wide spectrum electromagnetic shielding effectiveness measuring device according to claim 1, characterized in that: The ultra-wide spectrum receiving module further comprises a metal shielding box, in which the impedance converter, programmable attenuator, signal amplifier, peak detector, comparator, single chip microcomputer system and display are all packaged.

3. The ultra-wide spectrum electromagnetic shielding effectiveness measuring device according to claim 2, characterized in that: An opening is formed on the outer wall of the metal shielding box. A light-transmitting shielding film is installed at the opening of the metal shielding box. The light-transmitting shielding film is used for viewing the contents displayed on the display.

4. A method for measuring ultra-wide spectrum electromagnetic shielding effectiveness, the method being implemented based on the ultra-wide spectrum electromagnetic shielding effectiveness measuring device according to claim 3, characterized in that: The following steps are involved: S1. Adjust the relative distance, direction and antenna polarization between the ultra-wide spectrum transmitting module and the ultra-wide spectrum receiving module; S2. Start the ultra-wide spectrum receiving module and let it wait for a while, and then seal the shielded body under test. S3, enabling the ultra-wide spectrum transmitting module to transmit ultra-wide spectrum electromagnetic waves of a certain period; S4. The ultra-wide spectrum receiving module controls the attenuation value of its programmable attenuator to be set from large to small, and respectively receives the ultra-wide spectrum electromagnetic waves attenuated by the shielding body under test until the ultra-wide spectrum signal can be stably received. The ultra-wide spectrum receiving module collects the peak value and period of the ultra-wide spectrum signal; If the sampled period is the same as that of the transmitted ultra-wide spectrum signal, the measurement data is considered normal. The peak value collected is multiplied by the attenuation factor set by the programmable attenuator to obtain the shielding peak value of the ultra-wide spectrum signal after shielding and attenuation by the measured shielding body. The shielding peak value and period of the ultra-wide spectrum signal are displayed on the display. If the programmable attenuator has reached its minimum value, that is, the attenuation value is 0dB, and the ultra-wide spectrum signal cannot be stably received or the measured period is significantly different from the period of the transmitted ultra-wide spectrum signal, it is considered that the ultra-wide spectrum signal is less than the detection limit of the ultra-wide spectrum receiving module after being attenuated by the measured shield, and the display shows that it is below the detection limit; S5. Stop the ultra-wide spectrum electromagnetic wave transmission of the ultra-wide spectrum transmitting module, and the ultra-wide spectrum receiving module automatically stops data collection and keeps the previous display content; S6. Remove the shielding body to be tested and read the peak value and period on the display in the ultra-wide spectrum receiving module; Keeping the relative distance, direction and polarization between the ultra-wide spectrum transmitting module and the ultra-wide spectrum receiving module unchanged, and the transmitting power of the ultra-wide spectrum transmitting module unchanged, repeat the above process, measure the peak value of the ultra-wide spectrum signal without shielding attenuation by the measured shielding body, and obtain the reference peak value of the ultra-wide spectrum signal; S7, stopping the ultra-wide spectrum electromagnetic wave emission of the ultra-wide spectrum transmitting module, dividing the ultra-wide spectrum reference peak value by the shielding peak value after the ultra-wide spectrum signal is shielded and attenuated by the shield under test, to obtain the ultra-wide spectrum shielding effectiveness of the shield under test, and taking the logarithm to obtain the decibel number of the ultra-wide spectrum shielding effectiveness; If the shielding peak is less than the detection limit, the ultra-wideband shielding effectiveness is greater than or equal to the reference peak divided by the detection limit.

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