λ/2 rejection filters are band stop devices usually useful for one frequency only. In this paper the multi frequency aspects of the filter using overlay of Ni.0.7-XCoXZn0.3Fe2O4 thick film is reported. Composition dependent shifts in the resonance notch is obtained. In the Ku band double resonances are obtained with an increase in the rejection. Due to increase in cobalt content the Q of the filter and the effective dielectric constant increases. Tuning of the filter due to composition of the Ni.0.7-XCoXZn0.3Fe2O4 thick film overlay has been obtained in the X and Ku band. From the perturbations the complex permittivity and permeability of the ferrite thick films have been evaluated.