In this research, the M-type strontium hexaferrite nanoparticles, SrFe12−2x(Mn0.5Cd0.5Zr)xO19, (x=0.0−1.6), have been synthesized by the coprecipitation method. X-ray diffraction, a field emission scanning electron microscope, a vector network analyzer and a vibrating sample magnetometer were used to characterize their structures, electromagnetic and microwave absorption properties of samples. The results indicated the formation of hexaferrite structure for all samples. The sample with x=1.4 showed a minimum reflection loss of −52dB at 14.5GHz with reflection loss less than −20dB over the extended frequency range of 13.6–16.5GHz. Finally SrFe9.2(Mn0.5Cd0.5Zr)1.4O19 could be considered as a good candidate for thin microwave absorbers in the gigahertz range.