Multimode Resonator Technique in Antennas: A Review

During the past several decades, the multimode resonator (MMR) technique has been extensively investigated and widely used, with successful exploration of a variety of high-performance patch antennas, slot antennas, dielectric resonant antennas, dipole antennas, and so on. In this review paper, we summarize the research milestones for these MMR antennas worldwide as one of the most contributive research teams in this field. First, the basic working principles of the MMR technique are clearly illustrated and studied, including mode excitation, mode suppression, impedance performance improvement, and radiation performance improvement. Next, the research topics regarding impedance performance enhancement, i.e., wide-bandwidth operation, multibandwidth operation, and mutual coupling reduction, based on the MMR method are intensively described. After that, the relevant works on radiation performance enhancement, i.e., high-gain, wide-beamwidth, multibeam, multipolarization, low-cross-polarization, filtering-response, and leaky-wave antennas, based on the MMR method are extensively illustrated. By using this technique, several ideas about operating frequency reallocation, electric-field null control, radiation pattern reshaping, and efficiency null generation of the antennas are proposed and demonstrated by our team for the first time. In addition, the application of the MMR technique for wireless communication systems is introduced and presented, such as implant communication, wireless power transfer, and multiple-input multiple-output communication. With these arrangements, exploration and reporting of more interesting and useful MMR design methods can be anticipated in the future.