Compact microstrip antenna with triple-band triple-mode characteristics

One novel microstrip antenna with triple-band triple-mode (TBTM) is proposed in this paper. In the lower frequency band, the antenna operates in the dipole mode with omnidirectional radiation pattern along the YOZ plane. In the middle frequency band, the antenna operates in the dipole mode with omnidirectional radiation pattern along the XOY plane. While in the upper frequency band, the antenna works in the patch mode with directional radiation patterns along the Z-axis direction. Due to the mutual-coupling periodical circular patches and inductance metal pins connecting the upper and lower patches, the three modes can be excited in three different bands. The surface current distribution is introduced to analyze the antenna working principle. This single-feed single-layer patch antenna has potential application value in wireless communications for its compact structure, multi-band function and diversified radiation patterns.