А.V. Kozar - Professor, Department of photonics and microwave physics, M.V. Lomonosov Moscow State University. E-mail: avk@phys.msu.ru А.V. Trofimov - Post-graduate Student, Department of photonics and microwave physics, M.V. Lomonosov Moscow State University. E-mail: av.trofimov@physics.msu.ru

Quite often in modern sub microwave technology the problem of highly reflective loads matching appears. To solve this problem mul-tilayer interference absorbers are widely used. In this case, making a multilayer mirror with a reflection coefficient equal to the modulus of the reflection coefficient of the load, and with the phases that differ by, and than installing this mirror in front of the load is sufficient for the total energy absorption in the load. However, this solution has obvious disadvantages. Firstly, since the load is highly reflective, the first mirror must have a very high reflectance, i.e. must contain a relatively large number of layers. This leads to significant undesirable absorption in the mirror and to the large geometrical dimensions of the mirror, that makes such a method of solving the problem of matching inappropriate in many cases. For example, the cryogenic devises require the minimum possible heat capacity of the matching structure. The method that uses the dispersion properties of the waveguide line is free of these disadvantages. Such method can provide full absorption of the electromagnetic wave energy in the highly reflective materials (metals) using a single quarter-wave layer. This work consider a new type of matching structures for highly reflective materials in the microwave frequency range. Matching structures of this type have several advantages: compactness, simplicity of construction, and in addition there is no significant restric-tions to the choice of the dielectric for making matching layer. The matching structure consists of a dielectric layer mounted close to the load made of highly reflective material. Both highly reflective load and matching layer are set in a rectangular waveguide. Waveguide dispersion plays a key role in the matching the loads. In this study, the method of impedance characteristics is used to analyze the interaction of electromagnetic waves with the matching structure. Experimental studies were carried out in frequency range 9-10 GHz. The experimental results obtained in this study agree with theoretical predictions. The conducted research has shown the possibility of providing the complete wave energy absorption in the highly reflective material using the interference phenomena in the layered structure and the dispersion characteristic of the waveguide line. The obtained results allow making multilayer structure matching with specified characteristics for the specific applications in microwave radio physics and also in the optical and infrared ranges.

 

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