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Microwave mousse chambers are also known as "absorption chambers" and "non-echo chambers", referred to simply as mousse chambers. In the mist room, the room's six walls are affixed with absorbent material, so that most of the electromagnetic energy that is shot into the six walls is absorbed, the reflection is small, and the free space can be better simulated.
In the 1950s, in developed countries, the United States and the former Soviet Union built microwave darkrooms for various radio measurements, such as antenna measurement, RCS measurement, simulation, remote sensing, fuse, etc. After the 1980s, several EMC darkrooms were built for EMI and EMS measurements.
In the past 30 years, with the improvement of the performance of absorbent materials and the need of scientific research and development, the construction of microwave dark houses has been increasing. In order to meet the measurement requirements of radar antenna and other related technologies, microwave dark rooms of different types and sizes have been established in Order to improve measurement accuracy and research quality. In recent years, China has yet to build ANC darkrooms (semi-open darkrooms).
The electrical properties of darkrooms are mainly characterized by the characteristics of static areas, including the size of static areas, the reflection level of static areas, cross-polarization, multi-path loss, field uniformity and operating frequency. Frequency range and other parameters.
The above electrical performance indicators are not only related to the performance of absorbent materials, but also closely related to the structural size of the darkroom (i.e., the ratio of length, width and height), but also to the placement of auxiliary facilities in the darkroom: lighting, sirens, camera base, doors and windows, aisles, etc. A good mousse chamber should be fully planned and designed before civil construction. First, you should coordinate the scale dimensions of length, width, and height. In general, width equals height (which is beneficial for improving cross-polarization). The optimum height, width, length of about 0.6 times to ensure that the material's incoming angle at the maximum test distance does not exceed 50 degrees, and the absorption performance is effectively utilized.
1. Build a microwave oven darkroom and dark box to form a non-reflective chamber to simulate free space:
Microwave m2 chambers are widely and effectively used to measure antenna direction maps, gain, polarization, impedance coupling and other parameters. In the field of defence, it is used to measure the equivalent scattering cross-sections of satellites, missiles and various flying objects. Darkrooms can also be used effectively to measure the sensitivity of the entire machine, system consistency, magnetization rate, effective radiation power, alignment of radar vision in position, beam adjustment of the optical system, etc.
2. Cover a variety of reflected objects to improve the test environment conditions:
In antenna measurement and radar detection technology, objects that reflect larger objects, both indoors and outdoors, such as test rods, racks, turntables, instruments and equipment, buildings on and on the ground, trees and railings, often produce large reflections, but cannot be avoided. Therefore, the absorbent material needs to be covered and shielded to reduce the impact of environmental reflections and improve measurement accuracy, and avoid incorrect targets.
3. Disguise and hide military items to prevent radar radiation and detection:
In modern times, some military reconnaissance aircraft, spy satellites, mines and military equipment are often covered or coated with special coatings of absorbent material or absorption coatings to prevent detection of radar waves and achieve covert purposes.
4. Stop microwave radiation and protect the human body:
Nowadays, with the rapid increase of electromagnetic energy diffusion and pollution, some parts with large radiation can be made into partitions to prevent microwave radiation. It is conceivable that with the development of an absorption coating or an absorbent coating cloth, it can be made into a microwave to protect the human eye, allowing the debris to be absorbed rather than diffused and contaminated again.
5. Make a small probe antenna to sample and test the radiation field:
By opening a small hole in the absorption plate and pasting it on the end face of the wave guide 12, the radiation field can be sampled and received directly for testing. In this way, the small hole receiving probe does not affect the distribution of the space radiation field, but also can achieve a small range of sampling. The sampling signal is then amplified by detection and received for recording. Only small hole probes can move up and down, or even rotate, to detect the distribution of the field.
6. Make a "cold" and "hot" negative cross-section of the micro-Bosnia-Herzegovina body to calibrate the measurement of antenna noise temperature:
Using microwave "absorption", "black bodies" (e.g., room temperature "black bodies" and liquid nitrogen "black bodies") set and wrap the interface of the antenna feeds separately at different physical temperatures to form a standard noise source, i.e. an equivalent negative cross-section, to calibrate the antenna noise temperature. This "black body" calibration is accurate and reliable and is now widely used.
7. Make a rotating absorption bezel for mechanical modulation on the antenna interface:
8. Make an antenna absorption tunnel to reduce the wide-angle radiation of the antenna:
9. Absorption isolation and separation to decouple:
10. Make the negative part of the wave guide absorption terminal to achieve transmission matching:
In short, microwave absorbent materials are becoming more widely used. For different purposes, different types of microwave absorbent materials with different compositions, compositions and process structures need to be selected. And show different physical characteristics, such as high physical strength, low thickness, light weight, greater flexibility, good flexibility, fire resistance, weather resistance, magnetic conductivity, high-performance broadband, high power, high and low temperature and low temperature capacity. Cost.
tage:Absorbing material Magnetic sheet