A 24 GHz wafer scale electronically scanned antenna using BST phase shifters for collision avoidance systems

Low cost radar collision warning systems are under development at a number of companies. 24 GHz is typically chosen as the optimum frequency for low cost and good system performance. Antennas for these systems must scan a wide field of view very rapidly while maintaining good gain and low sidelobes. Most importantly, the antennas must be low cost. This paper describes a 24 GHz electronic scanning antenna (ESA) using phase shifters based on BST (barium-strontium titanate) varactors. The entire antenna is fabricated on a 100 mm sapphire wafer using a simple six-mask process. The BST is deposited using a proven thin film CVD process. Phase shifter insertion loss is less than 6 dB. A field of view greater than +/-45 degrees is demonstrated. Estimated production cost for the antenna is in the tens of dollars