A method to achieve a photonic crystal fiber (PCF) with high birefringence for polarization maintenance in short range THz communication systems is introduced in this paper. Rectangular air slots are etched in the core region of the fiber; they make the X-polarized (XP) and Y-polarized (YP) propagation modes have different propagation constants, thus leading to the higher birefringence. In contrast to the widely-used fully-slotted (FS) configuration in which the fiber core is almost fully occupied by air slots, the proposed PCF has a partially-slotted (PS) core. The air slot in the core center is absent; only the dielectric background is present. Comparisons are made between the fully-slotted and partially-slotted PCFs to illustrate that the PS PCF overperforms the FS PCF. After optimization, the PS PCF attains a high birefringence value of 0.069 and a total loss of 0.071 cm-1 at 1.0 THz. Over a broad 0.4 THz working band, from 0.53 to 0.93 THz, the dispersion is within 0.06 ps/THz/cm.