Composite Materials with Other Kind of Matrix

**129**

**Chapter 8**

Systems

**Abstract**

**1. Introduction**

Investigation of Shielding

Effectiveness of M-Type Ba-Co-Ti

Hexagonal Ferrite and Composite

*Charanjeet Singh, S. Bindra Narang and Ihab A. Abdel-Latif*

Ferrites are a wide class of materials that are still a very rich field of scientific interest and under the scope of recent research. The polycrystalline Co2+-Ti4+ substituted Ba hexagonal ferrite has been synthesized by the standard ceramic method. The vector network analyzer has been incorporated to measure different microwave parameters at X-band (8.2–12.4 GHz) frequencies. The microwave shielding effectiveness is evaluated by S-parameters for near field and AC conductivity as well as skin depth for far field. The doping of Co2+ and Ti4+ ions causes absorption in composite x = 0.5 to exhibit good shielding effectiveness and it exhibits large 20-dB bandwidth of 4.70 GHz in the near field and 3.60 GHz for far field respectively. The AC conductivity increases with frequency in composites x = 0.1, 0.3, and 0.5 and skin depth decreases with frequency in all composites. The shielding effectiveness,

AC conductivity, and skin depth are correlated to each other.

**Keywords:** ferrites, hexaferrite, microwave shielding, AC conductivity

Ferrites are a wide class of materials containing iron. These materials are formed in different crystalline symmetries. A simple form of ferrites is the spinel AB2O4 of cubic structure [1–9]. The orthoferrites ABO3 are another important form with an orthorhombic perovskite crystal system [10–19]. The third class of ferrites are garnets of form A3B5O12 [20–29]. The fourth class, termed as hexaferrites, may be divided into five main groups: M-type (AB12O19), W-type (AMe2B16O27), X-type A2Me2B28O46, Y-type A2Me2B12O22, and Z-type or A3Me2B24O41 [30–49]. The preparation of these materials and their characterization are very rich topics because of the wide range of applications and the cheap materials obtained. Ferrites are a very interesting class of materials whose wide range of applications are related to electromagnetic interference suppression as well as their use in radar absorbing material (RAM) coatings [50]. From this point of view, great scientific interests are devoted to use these materials as RAM devices [51–54]. In this work the intensive highlights is devoted to the microwave applications and which class is the best candidate for this application.

Materials in Microwave X-Band

#### **Chapter 8**
