Abstract-This paper presents a polarization switchable antenna
for UHF RFID Reader. The UHF-RFID has the bandwidth from
920 MHz to 925 MHz, and the center frequency is 922.5 MHz.
The antenna is composed of main radiation part and the corner
which is separated by a slot. The antenna can switch between
circular and linear polarization by shorted or open between the
main patch and the corner. The antenna structure is simple
because of using the single probe to feed the microstrip antenna.
For circular polarization, the pattern is unidirectional beam with
the directivity of 8.69 dBic at the center frequency. For linear
polarization, the pattern is unidirectional beam with the
directivity of 8.67 dBi at the center frequency. The obtained
bandwidth is 45 MHz for circular polarization and 27 MHz for
linear polarization.