Broadening of Operating Frequency Band of Magnetic-Type Radio Absorbers by FSS Incorporation

Abstract

Abstract-Problems of the theory of radio absorbers (RAs) involving frequency selective surfaces (FSSs) are considered. A design procedure for these RAs is described that takes into account the multiparameter character of the problem and allows one to determine the optimal characteristics of an FSS that provide the maximal operating bandwidth. RAs for a range of 1-17 GHz are obtained on the basis of polymer composites filled with carbonyl iron and Co2Z ferrite, into which an FSS in the form of a biperi-odic array of thin metal rings is embedded. It is shown that the application of such an FSS allows one to increase the operating frequency bandwidth of a magnetic-type RA by a factor of more than 1.5 virtually almost without increasing the thickness of the absorber. Substantially, several types of FSSbased layered magne-todielectric RAs have been produced by compressing molding technique, including a 3-mm-thick RA with an operating bandwidth of 1.5-2.7 GHz, a 2-mm-thick RA with an operating bandwidth of 1.7-4.4 GHz, and a 1.6-mm-thick RA with an operating bandwidth of 6.7-16.1 GHz. Index Terms-Electromagnetic

Optimized Frequency Selective Surface for the Design of Magnetic Type Thin Broadband Radio Absorbers

“…The calculation of the frequency dependence of reflection coefficient from the surface of RAs was performed via transmission line theory [2,6] using experimentally measured complex permeability (Fig. 3) and permittivity spectra (Fig.…”

“…One of the means to address these concerns is the use of radio absorbers (RAs). For the optimal design of RAs the reduction of weight and thickness as well as broadening of operating frequency range of absorber must be considered simultaneously [1,2]. The reflection coefficient (R) is a parameter that characterizes the absorbing ability of RA in decibels (dB).…”

“…Any RA operates in a limited operating frequency range. One of the methods for expanding the bandwidth of RA without increasing its thickness is the incorporation of frequency selective surface (FSS) into the structure of RA [2][3][4]. FSS consists of a dielectric plate which usually comprises periodically spaced planar conductive elements.…”

Radar-cross-section reduction of wind turbines. part 1.

“…Circuit-analog absorbers are actually a variant of Jaumann absorbers. Whereas Jaumann absorbers contain uniform resistive sheets, circuit analog absorbers insert sheets consisting of periodic patterned circuits, also known as frequency selective surfaces (FSS), containing both conductive and resistive materials [3,10,11,12,13,14,15,16,17,18,19,20]. Figure 3 illustrates some common CAA circuit patterns.…”

CaCu3Ti4O12 particles and MWCNT-filled microwave absorber with improved microwave absorption by FSS incorporation

“…As mentioned above, compared with the single absorber (MWCNTs or CCTO particles)-filled composites and MWCNT-, and CCTO particle-filled epoxy composites are good candidates for fabricating microwave absorbers with high absorption, due to the significant potential to obtain suitable complex permittivity and dielectric loss. In addition, it has also been indicated that the design of microwave absorbers with frequency-selective surface (FSS) can be used to improve their microwave absorption [17][18][19][20][21][22][23][24]. Using a FSS and RAMs design, microwave absorption can be enhanced by optimizing the impedance matching and attenuation characteristic of the absorber, adjusting the pattern, square resistance of the FSS.…”