In this paper, we present a new planar fluxgate magnetometer structure. The sensor has the orthogonal fluxgate configuration which makes the detection part independent of the excitation mechanism. The sensor consists of a ferromagnetic cylindrical core covering an excitation rod, and planar coils for signal detection. The fabricated sensor has a linear range of ± a sensitivity of 4.3 mV/mT, and a perming below 400 nT for 200 mA peak sinusoidal excitation current at 100 kHz. The effect of demagnetization on the sensitivity, linear range, and perming for this structure is demonstrated by varying the length of the ferromagnetic core.