The design and development of low cost variable frequency ultrasonic phased array is presented. The research outlines the working principles of a traditional piezo-electric ultrasonic range sensor and elaborates on the improvements in propagation and reception that can be achieved using a phased array approach. The phased array approach is extended to work with aircapacitive ultrasonic transducer, the design and development of which is outlined in the work detailed in the thesis A simulation study of the excitation modal frequencies comparing the analytical and the numerical air-damped approach are presented. A circuit design to generate the phased array algorithm is designed and developed. Using time of arrival approach the position of the target is determined. The TOA technique for an air-capacitive transducer produces themaximum range allows the sensor with a range of 55 cm with an angular resolution of 15 degrees.