We present the design and optimization of a wide-angle and broadband operational polarization beam splitter by simultaneously satisfying a high reflection of the transverse magnetic (TM) wave and high transmission of the transverse electric (TE) wave using coupled plasmonic waveguides. The finite-difference time-domain (FDTD) method is used in the optimization process where various structural parameters are scanned, and design maps applicable to most III-V material systems are established. Wide-angle operation of over 0° to 70° and ultrabroadband operation over $500\mathrm{nm}$ with insertion loss less than $-1.0\mathrm{dB}$ are predicted. The extinction ratio is better than $-17\mathrm{dB}$ , and it is realizable on a chip as small as $0.1\times 2\mu {\mathrm{m}}^2$ .