研究期間：10108~10207;In the project, a novel design for dual-band circular polarized cavity-backed slot antenna will be proposed. The proposed antenna is consisted of a feeding slot, a cavity and a radiating slot. The antenna is fed by microstrip coupled feed. The dual-band response of the antenna is using a dual-band feeding network and radiated by the radiating slot through the cavity. In order to generate two orthogonal electrical fields, two radiating slots with L-shaped arrangement will be applied.The inductance or capacitance load across the radiating slots are applied to produce the 90 degree phase difference between two radiating slots for circular-polarization. The proposed antenna design will be validated by realizing the antenna at GPS (1.575 GHz) and WLAN (2.4-2.485 GHz) frequencies. The fractional bandwidths of GPS and WLAN are 24 MHz and 85 MHz, respectively. Moreover, the two operation frequencies are not harmonic frequencies of the antenna, and the fractional bandwidths of GPS and WLAN are greatly difference.