This work investigates electromagnetic properties of half-dense ceramics with compositions Ni 0.5 Zn 0.3 Co 0.2 Fe y O 4-d where y = 1.98 (Iron deficient, noted ID) or y = 2.3 (Iron in excess, noted IE). IE and ID materials are obtained by chemical coprecipitation route. The obtained nano-sized powders are pressed and annealed at two temperatures (800 °C, 900 °C), so has to obtain half-massive ceramics. Ferrous and ferric ions coexist in the crystalline structures, but the former in a less extend for ID ferrite. The concomitant influences of Fe 2+ and Fe 3+ on the dielectric and magnetic losses (e 00 /e 0 and m 00 /m 0 , respectively) are considered at frequency up to 6 GHz. The permeability dispersion changes from relaxation-like to resonance-like with the decrease in ferrous ions. In reason of the relaxing-like behavior of Fe 2+ , and because of a relatively high amount in Fe 2+ , IE sample shows lower total losses (magnetic and dielectric) than ID sample. These conclusions applied for T A = 900 °C. At frequencies above 700 MHz, the total loss values (IE and ID samples) are prohibitive for antenna downsizing whatever is the firing temperature value (800 °C and 900 °C). Whereas at frequencies below 700 MHz Ni 0.5 Zn 0.3 Co 0.2 Fe 2.3 O 4+d may leads to better antenna performances than Ni 0.5 Zn 0.3 Co 0.2 Fe 1.98 O 4-d .