A wideband aperture-coupled microstrip array for an automotive radar sensor

Abstract

The development of automotive radar sensors is a hotly contested area of research that has tremendous sales volume potential for the manufacturers able to meet the low pricing guidelines set for these products. Traditional PTFE laminate materials have excellent electrical properties of low dielectric loss tangents, but the material and fabricating costs for these circuits are relatively expensive, and were not deemed acceptable for a viable automotive radar program. The recent introduction of inexpensive, commercial grade laminates is extremely attractive for these applications. In this thesis the design of a commercial grade laminate, aperture fed microstrip patch antenna, with coplanar parasitic elements, is pursued. This antenna element will then be used in the design and development of an experimental prototype microstrip array for use in an automotive back-up-aid radar sensor. The numerical analysis tools required for quick, efficient, and moderately accurate design of this microstrip antenna configuration were not available at the time and it was the intention of this research to create such a tool. During this research, a number of commercial analysis tools became available which were more than adequate for the current research. Two commercial method-of-moment analysis software packages were acquired. Using the knowledge gained from the theoretical and numerical analysis of this antenna element, a prototype antenna was designed, fabricated, tested, and analyzed with respect to relevant performance criteria. A 16-element array using this new antenna element is then developed from concept to a complete analysis of the performance obtained from a fabricated antenna array. In this thesis it is demonstrated that with the proper design, of microstrip circuits produced on commercial grade laminates, satisfactory performance at microwave frequencies is achievable. The results obtained here are expected to lead to the design of other products on these inexpensive laminates.