Coupling-Feed Circularly Polarized RFID Tag Antenna Mountable on Metallic Surface

Circularly Polarized Dodecagonal Patch Antenna With Polygonal Slot for Rfid Applications

“…In the even mode (oriented about the Y axis), the surface current is forced to traverse more length around the slot and hence the resonant frequency ω e is reduced. If a second orthogonal cut is made at the center [3], it will enhance the electrical path of the odd mode and the corresponding resonant frequency will be reduced. In the proposed structure, instead of making an orthogonal cut, the central width of the hexagonal slot is made larger than the top and bottom width.…”

“…A wide variety of perturbation methods have been adopted in literature for designing a single feed circularly polarized microstrip antenna. One 'V' shaped slot embedded into a cross shaped rectangular patch antenna [2], square patch embedded with a cross slot and an L-shaped open-end microstrip line linked to a tag chip, terminated by a shorting pin on the other end and capacitively coupled to the patch [3], an arrowhead-shaped slot is embedded in the first quadrant along the diagonal axes of a square patch [4], a circular patch antenna with central elliptical slot [5], two stacked patches fed with an S-shaped impedance-matching network [6] are some of the distinct techniques employed to excite circularly polarized radiation.…”

Hexagonal Circularly Polarized Patch Antenna for RFID Applications

“…In the even mode (oriented about the Y axis), the surface current is forced to traverse more length around the elliptical and circular slots and hence the resonant frequency ω_e is reduced. If a second orthogonal cut is made at the center [13], it will enhance the electrical path of the odd mode and the corresponding resonant frequency will be reduced. Here in this proposed structure, the effect of more electrical length is achieved by the two circular slots and the appropriate dimension of secondary radius for the elliptical slot.…”

“…Various perturbation methods have been adopted in literature for designing a single feed circularly polarized microstrip antenna. Truncating the corners of the hexagonal patch and inserting slits [1], One "V" shaped slot embedded into a cross shaped rectangular patch antenna [2], asymmetric-circular shaped slotted microstrip patch antennas with slits [3], two crossed PIFA [4], a cross-strip embedded along the Xshaped slot for a proximity-fed technique [5], antenna using a set of slits and slots [6], a cross slot embedded on the radiating patch [7], truncating corners of a square patch and inserting slits of different lengths at the edges of a square patch [8,9], two slits inserted at the annular-ring patch [10], embedding a circular central elliptical slot on a circular patch [11], truncating the corners of a polygonal patch are some of the techniques employed to radiate circularly polarized waves. In this structure, a hexagonal microstrip patch antenna with the perturbation technique of embedding a central elliptical slot and two circular slots is proposed.…”

Novel circular polarization antenna for UHF RFID application

“…Therefore, the polarization mismatch between them would result in that only half of the transmission power is received by tags. However, if the tag antenna is also circularly polarized, the power received by the CP tag antenna can be improved by 3 dB, and the maximum reading range can thus be increased by 41%, theoretically [2].…”