The 76-81GHz frequency modulated FMCW radar product (also known as millimeter wave radar) has important applications in remote target detection, strong smoke and dust environments, remote imaging, multispectral imaging, and other areas due to its use of millimeter wave bands with higher frequencies than Ku band radar. It can detect smaller targets than microwave radar and achieve more accurate positioning, with higher resolution and stronger confidentiality.The general principle of FM continuous wave radar level meter is that the radar emits electromagnetic waves at the top of the tank, which are reflected by the medium and received by the radar. The frequency difference between the received signal and the transmitted signal δ F is proportional to the distance R from the surface of the medium: R=C (velocity)* δ F (frequency difference)/2/K (frequency modulation slope). Because the speed of light C and the frequency modulation slope K are known, the frequency difference is estimated δ f. The distance R of the radar installation position material surface can be obtained, and then the height of the material level can be obtained by subtracting the spatial distance from the radar to the material surface (referred to as the empty height) from the known total height of the tank body.
What is millimeter wave electromagnetic wave: Usually, electromagnetic waves in the frequency domain of 30-300GHz (with wavelengths ranging from 1 to 10 millimeters) are called millimeter waves, which are located in the wavelength range where microwave and far-infrared waves overlap, thus possessing the characteristics of both wave spectra. The 76-81GHz band of this product is currently the least understood and developed area for application, with the following characteristics.
1. Very good transient performance: the pulse width of the electromagnetic pulse in this band can be narrow at the sub picosecond (ps) level, so it can be used for time resolution research on various materials and measurement of molecular structure; By using sampling measurement technology, the interference of far-red background noise can be effectively suppressed.
2. There is a wide bandwidth: the pulse source in this band usually requires only a few periods of electromagnetic wave oscillation, which is close to the band of vibration and rotation energy levels of many biological macromolecules, dielectric, semiconductor, superconductor, and molecular vibrations energy levels of film materials. Therefore, this band spectrum can be an effective means of detecting material information in the millimeter wave band, which is very suitable for measuring material absorption spectrum and can be used for qualitative identification applications.
3. Coherence: dipole oscillation driven by coherent current or nonlinear frequency difference effect of coherent laser pulse;
4. Low energy: Millimeter wave photons have only a few millielectron volts of energy and do not undergo X-ray ionization or damage to the substance to be tested, making it difficult to damage the substance to be tested.
5. Strong penetrability: For non-polar materials, they have strong penetrability, and many non-metallic non-polar materials have less absorption of radiation in this band. Therefore, they can be used to detect the internal structure of materials. For example, ceramics/cardboard/plastic products/foam are transparent to electromagnetic radiation in this band, and can also be used for airport/station safety monitoring, such as detecting machinery/explosives and drugs, or for circuit board welding detection.
6. Easy to be absorbed by polar molecules: This band has less scattering in non-uniform substances and can detect and measure water vapor content. Material composition can also be studied or quality control can be carried out by analyzing their characteristic spectra.
As a 78GHz band radar used in the field of industrial measurement, high-precision, non-contact level and liquid level measurement has unparalleled advantages compared to other ordinary microwave pulse radars and guided wave radars. Its extremely narrow beam and penetration ability make it more suitable for ultra complex working conditions without compromising measurement performance.
application area
1. The electromagnetic wave emission angle of the product is less than 3 °, suitable for measurement in narrow spaces or guided wave pipelines
2. The product can reach a measurement range of 120M, suitable for measuring large storage tanks
3. The blind spot for product measurement is within the range of 7-8CM, suitable for measuring small storage tanks
4. The product has extremely high measurement accuracy and is suitable for high-precision metrological level measurement
5. The product has rich echo processing algorithms and empirical data of various working conditions and environments; For extremely harsh working conditions such as strong dust and steam, or for storage tanks with special processes such as stirring and heating rods, it has unique advantages that other similar products do not have
Product Features
1. 76GHz-81GHz FM Wave Radar
2. 5GHz ultra large FM scanning frequency width, with a wide range of applications
3. Supports standard HART, RS485/MODBUS bus protocols
4. Support for upper computer settings software, tank side tables, and other operating methods
5. 24VDC power supply
6. Simple installation structure, suitable for various installation forms on site
1、Basic parameters
Transmission frequency | 77GHz~81GHz, frequency modulation scanning frequency width 5GHz |
measuring range | 120m |
measurement accuracy | ±1mm |
Beam angle | 3°、8° |
Using the range of dielectric constant | >=2 |
Power supply range | 18~28.0VDC,220VAC 4-wire/2-wire system |
Communication method | MODBUS bus/HART |
signal output | 4-20mA or RS-485 |
Fault output | 3.8mA, 4mA, 20mA, 21mA, hold |
Field operation/programming | one hundred and twenty-eight × 64 dot matrix display screen/4 buttons Configurable upper computer setting software |
Industrial temperature/humidity | -40~85℃/≤95%RH |
Shell material | Aluminum casting, stainless steel |
Antenna type | Lens antenna, can be equipped with lens antenna cover/anti-corrosion antenna/antenna heat dissipation paste/quartz isolation flange plate |
Process pressure | -0.1~2MPa |
Product size | Ø100*270mm |
Cable entry | M20*1.5 |
Recommended cables | AWG18 or 0.75mm² |
Protection level | IP67 |
Explosion proof level | ExdIICT6 |
Installation method | Thread or flange |