A high performance and cost effective biosensor is designed using a radial contour-mode disk resonator (RCDR). This sensor measures tiny biological mass attached on a disk vibrating at a high frequency, producing high quality of output signal. A series of analysis and simulation models is developed to predict the mass sensitivity, dynamic stability, and motional resistance of the RCDR biosensor with given geometry and signal input. In order to decrease motional resistance while keeping the fabrication cost low, a layer of dielectric material is deposited within the capacitor gap. In designing the RCDR biosensors, we employ Type I, II, and III robust design approach to design a device that is insensitive to various types of uncertainty associated with the fabrication processes and analysis models. A mathematical construct, error margin index, is employed for this robust design. Traditional optimization and robust design approaches are separately formulated, solved, and compared. From the design results, we observe that the RCDR is a promising bio-sensing device compared to the existing ones. [ABSTRACT FROM AUTHOR]