A Broadband Proximity-Coupled Stacked Microstrip Antenna With Cavity-Backed Configuration

A broadband cavity-backed proximity-coupled stacked microstrip antenna is presented. Due to the interaction of the two stacked patches, two associated resonances are produced. Unlike conventional proximity-coupled or cavity-backed microstrip antennas, the lower patch and the cavity of this antenna produce the coupled resonances. These devised methods make the antenna act as multiple resonances, conducing to a broadband impedance matching. The simulated and the measured results demonstrate a bandwidth over one octave (VSWR < 2). In the meantime, stable radiation patterns are obtained across the entire impedance band. The key parameters of the antenna are studied, and a prototype antenna that has a three-dimensional interconnection structure is provided.