The biggest feature of wedge-shaped absorbing materials is that they can split incident electromagnetic waves into two waves with the same frequency but different incident angles along two directions

    Wedge-shaped absorbing materialIt is a new type of absorbing material with a wide operating frequency band and low dielectric loss. It not only has good absorption performance, but also has a certain attenuation ability. Its biggest feature is that it can split the incident electromagnetic wave into two waves with the same frequency but different incident angles along two directions, that is, one is the incident wave obliquely incident, and the other is the incident wave obliquely incident.

This dual reflection characteristic gives it the ability to absorb waves in two directions, thereby achieving the goal of absorbing electromagnetic waves.

At present, wedge-shaped absorbing materials have become the most attractiveAbsorberOne of its application areas is very wide, such as military stealth technology, communication antenna covers, aircraft skins, etc; Used for automotive windshields, aircraft landing gear, and antenna covers in civilian applications.

1、 Research background

In recent years, with the development of radar, satellite and other equipment, higher requirements have been put forward for absorbing materials, such as having a wide frequency band, low dielectric loss, good mechanical properties, high thickness and thinness, as well as excellent high temperature resistance, corrosion resistance, etc. Therefore, we need to develop absorbing materials with advantages such as wide bandwidth, low loss, and thin thickness, and wedge-shaped absorbing materials are a new type of absorbing material with good performance.

2、 Absorption principle

The absorption mechanism of wedge-shaped absorbing materials is related to their geometric shape. When the incident electromagnetic wave is directed vertically downwards towards the wedge-shaped absorbing material, the wave first reflects within the wedge-shaped structure and then propagates around it; When the incident electromagnetic wave is obliquely directed upwards towards the wedge-shaped absorbing material, the wave first reflects within the wedge-shaped structure and then propagates around it, forming multiple reflection interfaces within a certain range. In this way, within the same material, the propagation directions of the incident wave and the reflected wave are opposite, and these two waves cannot meet. When they meet, electromagnetic waves in all directions of propagation are simultaneously absorbed, thus achieving the absorption effect. Therefore, when the thickness of the wedge-shaped absorbing material is small, its reflection coefficients in the X, Y, and Z directions are all very small. Therefore, it can achieve a wide and narrow absorption bandwidth without affecting the material thickness and dielectric constant.

3、 Numerical simulation

When the thickness is 2 mm, its absorption rates in the X and Y directions are 0.87 and 0.85, respectively. Adding 10g weight of aluminum to a 2mm thick sample, and then adding 100g weight of aluminum to a 1mm thick sample, the results showed that the absorption rates of the samples in the X and Y directions were 0.92 and 0.88, respectively.

4、 Experimental verification

Using full wave software toWedge-shaped absorbing materialThe absorption performance was simulated and tested, and the simulation results were basically consistent with the measured results. The test results show that the peak absorption rate of the material is greater than 90% in the range of 3-18 GHz. Its relative bandwidth (RCS) has reached 15% to 35%, meeting the needs of practical applications. When the thickness is 10 mm, its absorption bandwidth reaches 20 GHz (10.74 GHz~20.75 GHz).

The self-made sample was used for experimental testing, and the results showed that the reflection loss of the sample was significantly greater than the incident loss; The sample exhibits good absorption within the frequency range of 3-18 GHz; A minimum value appeared near 3 GHz, corresponding to a bandwidth of 10.74 GHz (2.96 GHz). This sample can be widely used in aviation, aerospace, radar and other fields.

5、 Summary

Wedge shaped absorbing material is a new type of absorbing material, which greatly expands the application range of absorbing materials. Due to its wide frequency range, low loss, and good absorption bandwidth, wedge-shaped absorbing materials have become a promising new type of absorbing material. With the deepening of research work and the continuous emergence of new theories and technologies, wedge-shaped absorbing materials will be more widely used.