# 6.7. Core Loss¶

## 6.7.1. Spheroidal Core¶

The core loss may be computed if the loss tangent of the core material is known or is available from published data. The loss tangent is defined in terms of a complex effective relative permeability, $$\mu_r=\mu_r^\prime-j\mu_r^{\prime\prime}$$, as $$\tan{\delta=\mu_r^{\prime\prime}/}\mu_r^\prime$$ [Simpson and Zhu, 2007].

Fig. 6.15 : ex15.

## 6.7.2. Cylindrical Core¶

Devore and Bohley gave the core loss formulation which is dependent complex permeability of core below [Devore and Bohley, 1977].

Fig. 6.16 : ex16.

Another core loss formulation for ferrite loaded FM receiver antennas was given [Lindberg and Kaikkonen, 2007]

$R_f=2\pi f\mu_0\mu_{cer}\frac{\mu\prime\prime}{\mu\prime}n^2\frac{A}{l}$

## 6.7.3. Core Data¶

Example catalog data of complex permeability as a function of frequency is shown below [Data Handbook of Soft Ferrites and Accessories, 2004].

Fig. 6.17 : core-data.

Another catalog data of Siemens EC52 ferrite core is given below [Kazimierczuk et. al., 1999].

Fig. 6.18 : core-data-siemens.