Compact Dual-Polarized Antenna With Enlarged Effective-to-Physical Aperture Ratio for Wireless Power Transfer and RFID

A composite approach is proposed to design a miniaturized dual-polarized antenna with high gain for wireless power transfer and radio frequency identification. The compact antenna has a small ground plane and a low profile. It consists of a patterned driven patch, an air substrate, a slotted ground, and feeding and parasitic patches. The current distribution on it is elaborately tailored to fulfill miniaturization and gain enhancement simultaneously. The multipolar analysis method is applied to guide and clarify the design process. The overall antenna size can be reduced to 0.3 λ
₀
×0.3 λ
₀
×0.015 λ
₀
, whereas the gain still reaches 5.6 dBi, implying an effective-to-physical aperture ratio of 3. Moreover, the input matching, port isolation, and cross-polarization suppression are also discussed. The proximity coupling approach and structural symmetry are utilized for performance improvement.