Compact Microstrip Antenna With Triple-Band Triple-Mode and Triple-Polarization Characteristics

This paper presented one novel microstrip antenna with triple-band triple-mode and triple-polarization (TBTMTP) characteristics. In the lower frequency band, the antenna operates in the linearly polarized (LP) dipole mode with omnidirectional radiation pattern along the YOZ plane which is like one horizontally located dipole antenna. In the middle frequency band, the antenna operates in the LP dipole mode with omnidirectional radiation pattern along the XOY plane which is like one vertically located dipole antenna. While in the upper frequency band, the antenna works in the circularly polarized (CP) patch mode with directional radiation patterns along the Z-axis direction. Three modes with different patterns were excited in three different bands because of the mutual-coupling periodical circular patches and inductance metal pins. By etching inverted L shaped slot in the down circular mental patch, CP is realized for the patch mode without affecting the other two modes. The surface current distribution is introduced to analyze the antenna working principle. Due to the compact structure, easy fabrication, radiation pattern selectivity and polarized diversity, this antenna has potential application value in wireless communications in future.