Switchable dual/triple-band circularly polarised slot antenna by using artificial transmission line

摘要

A single-feed dual and triple-band reconfigurable planar single layer circularly polarised (CP) slot antenna is presented. This novel low-cost slot antenna composed of L-shaped feeding stub with modified open split-ring resonator (MOSRR) and complementary split-ring resonator (CSRR). Multi-frequency operation with CP radiation characteristics is achieved by using artificial exciting stub with combining MOSRRs along microstrip feeding line and defecting CSRRs on it. By inserting two PIN diodes inside the MOSRRs, several wireless frequency bands over 2.4-5.5 GHz with capability of switching are obtained. The simulated and measured results show that the proposed antenna can switch between two states including one dual-band mode (3-3.45/4.5-5.2 GHz) and one triple-band mode (2.3-2.43/3.3-3.43/5.2-5.42 GHz) that covers most of the commercial wireless communication systems, such as WLAN (IEEE 802.11), LTE and WiMAX. Different characteristics of each state such as impedance and 3 dB axial ratio bandwidths, radiation patterns and gains of the proposed antenna will be presented.