An electrically small three-band multi-polarization cross spiral antenna

A novel electrically small multi-polarization antenna is suggested. The antenna is the planar structure, which is made of a single sided printed circuit board, and radiates circular polarization (CP) of a GPS band simultaneously with linear polarization (LP) of a RFID band and a mobile phone band. Its multi-polarization is achieved by using a dipole-fed cross spiral antenna (DF-CSA), which is the novel antenna invented by one of the authors, as a basic structure. At the same time, its electrically small structure is realized by adding fork-shape elements to the DF-CSA. This paper shows that the presented antenna have achieved making electrically small size and succeeded in radiating good CP simultaneously with LP. The suggested design is 35 square millimeters and radiates omnidirectional CP with 0 dBi or more gain and 62% or more efficiency within 28 MHz band-width.