Planar four-port quadri-polarization slot antenna for millimeter wave application

This paper presents a planar, vialess printed slot dipole antenna with polarization switchable characteristic. The proposed design comprises four input ports, and each input ports corresponds to different polarizations such as horizontal polarization, vertical polarization, right-handed circular polarization, and left-handed circular polarization. Because lumped diodes are not available in millimeter wave frequency band, polarization diversity antenna designs using diodes are not applicable. The proposed design does not require PIN diodes and DC biasing circuits, which makes it suitable to be used at higher frequency band. It can be easily printed on a circuit board and integrated with RF circuits using flip chip. The low cost and easy implement characteristic enables polarization agile antenna design for millimeter wave frequency band.