A Pattern Reconfigurable Multi-Mode Antenna Based on Circular Disk and Ring-Shaped Resonators

In this study, a miniaturized, pattern reconfigurable microstrip patch antenna based on the excitation of different modes of multiple resonators is designed, fabricated, and measured. The antenna composes of a concentric circular patch and a ring-shaped resonator. To miniaturize the antenna, the ring-shaped patch is loaded by capacitors. To obtain different patterns, radiator sizes are adjusted to yield different TM modes. The ring part is excited by two probes, whereas the circular patch is parasitically excited. The beam is rotated continuously by varying phase differences between these two ports. Measurements support that the beam can be steered from -40
⁰
to 40
⁰
.