Design of low-profile microstrip antenna with enhanced bandwidth and reduced size

An effective technique is presented to enhance the bandwidth and reduce the size of an ultralow-profile microstrip antenna. By loading multicouple staggered slots on the patch and using inset feed structure, two TM₁₀ modes can be excited at two close frequencies and matched well simultaneously. Designs based on the structures with four-, five-, and six-couple staggered slots have been made to demonstrate the effective technique. To the best designed results, the presented ultralow-profile microstrip antenna obtains a bandwidth enhancement of about two times and a size reduction of about 60% compared with the ordinary one. The technique is suitable for radio-frequency front-end antenna integration and package in microwave and millimeter-wave bands