The structural and dielectric properties of $Pb_{1-x}Sr_x(Yb_{\frac{1}{2}}Nb_{\frac{1}{2}})O_3$ (PSYN) system have been investigated by x-ray diffraction(XRD), transmission electron microscopy(TEM) and dielectric property measurement. It is observed that the curie point($T_c$) of pure $Pb(Yb_{\frac{1}{2}}Nb_{\frac{1}{2}})O_3(PYN)$ has not shown a notable change on increasing Sr doping concentration. It is also shown that the maximum dielectric constant became smaller with the increasing doping concentration. In addition to this phenomena, we observed that the x-ray diffraction intensity due to the antiparallel dipole ordering decreased with the increasing Sr content. From the above strudies of the superlattice reflections, it is deduced that $Sr^{2+}$ ions hinder the antiparallel displacement of Pb ions but doesn't affect the B-site ordered PYN superstructure. The dielectric properties at room temperature in PSYN system give rise to a good candidate as a resonator material at the microwave frequency range.
