In this paper, a CPW-fed reconfigurable clover-shaped antenna with switchable circular polarization is proposed. This antenna consists of a clover-shaped patch, four p-i-n diodes, and two pairs of quarter-circular-rings. By electrically controlling the four p-i-n diodes to form two orthogonal bow-tie shaped current paths, the proposed antenna can be operated in two modes: the left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) modes. Two pairs of quarter rings are used to improve the bandwidth and AR performance of the antenna. The measured 10-dB reflection coefficient and 3-dB axial-ratio (AR) bandwidth of the prototype antenna is approximately 12.3% and 19%, respectively, which is enough for some wireless applications such as WLAN IEEE 802.11 b/g (4%). Gain and radiation pattern are also presented.
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