Magnetic microbeads have acquired broad scope in immunoassay applications to detect pathogens causing dreadful diseases. In this work, we propose magnetic sensors using non-spiral planar microcoils to sense the presence of the microbeads with better sensitivity and fabrication simplicity. Experiments are performed by measuring the current induced in the sensing coil in the presence of iron oxide microbeads. Meanwhile, simulation studies of the sensors are conducted to verify the experimental results. A comparison of the proposed and the reported works on planar coil sensors are also presented. Improved limit of detection with reduced power consumption is observed to be the significant advantage of the induction-balance and differential sensors compared to the reported works.