## 1 Introduction  
The reduction of electromagnetic radiation (EMR) impact is very important for the protection of people frequently using electrical and electronic devices which can emit electromagnetic waves with frequencies that are potential hazards to health. The International Agency for Research on Cancer (IARC) based on literature reports classifies radio frequency electromagnetic fields as group 2B, which includes factors probably carcinogenic to human [1]. The most utilized range is the microwave range, which can be defined as 1 -40 GHz, as most of the modern point to point, wireless, and satellite communications occupy this range. Electrically conductive woven or knitted fabrics with particular EMR shielding properties not only offer an opportunity to counter these threats, but also can be applicable to develop radar absorbing materials (RAM), for use in the field of stealth technology to disguise a vehicle or soldier from radar detection [2]. EMR shielding within the given frequency range can be provided by corresponding EMR reflection or absorption, and in the best case by reflection and absorption at the same time. In order to absorb or reflect EMR, materials must interact with either the electric or magnetic field of the radiation. Textile materials with incorporated conductive additives or coated with special conductive formulations are electrically conductive and therefore interact with the electric component of EMR [3]. The desired property of EMR shielding textile materials is low transmission that means high shielding effectiveness--SE (dB). According to the requirements of EMR shielding textiles on general use [4], conductive textiles can be classified in five grades from a fair grade to an excellent one: fair--7 dB \(\geq\) SE \(>\) 5 dB; moderate--10 dB \(\geq\) SE \(>\) 7 dB; good--20 dB \(\geq\) SE \(>\) 10 dB; very good--30 dB \(\geq\) SE \(>\) 20 dB; excellent--SE \(>\) 30 dB. For EMR shielding applications, typically SE of at least 20 dB (indicates that 99% of the electromagnetic energy is reflected or absorbed by the material) is needed. SE of 30 dB indicates that 99.9% of the EM energy is reflected or absorbed by the material, with only 0.1% exiting the shielding material [5]. However, among EMR shielding textile materials only materials with substantial contribution to shielding from absorption have the potential to be used as radar absorbing materials (RAM). It is stated [6] that, depending on their practical use, such materials should be characterised by a high EMR absorption coefficient, even twice as high as their reflection coefficient within as wide a frequency band as possible. During the investigation of EMR shielding characteristics of the textile fabrics with different deposit of conductive additives [7] it was found that absorption dominated when the total EMR SE was below 20 dB and that reflectance dominated when EMR SE was above 20 dB. Hence, in order to be effective for a radar signature reduction application, SE must be not too high since such a textile material would be too reflective, resulting in the poor radar protection properties [8; 9]. There are various techniques to provide the textiles with electrical conductivity and provide them with electromagnetic properties: introduction of electrically conductive yarns (carbon fibres, metal fibre); metallization of fabrics or yarns (voltaic, vacuum vaporisation); lamination or coating of conductive layers onto the fabric surface with metal particles, transparent organic metal oxides, carbon or inherently conducting polymers (ICPs). Variable electrical conductivity, electromagnetic shielding, electrostatic properties, and in comparison, the low cost of ICPs, have led to the investigation of potential applications of these materials not only as corrosion protectors, sensors, polymer actuators, but also as electromagnetic shields and radar absorbers. In contrast to some commonly used metallic shielding materials, conducting polymers not only reflect but also absorb EMR in the microwave frequency range [10; 11].