Unified Design of Dual-Band and Triband Dual-Sense Circularly Polarized Patch Antennas Under Quad-Mode Operation

A quad-mode unified design approach for dual-band and triband dual-sense circularly polarized (CP) antennas is proposed. The four boresight radiating modes are obtained by loading an open-ended stub and a series resonator on the patch. The characteristic mode analysis is employed to reveal the operational principles of the patch. The implementation of dual-band and triband dual-sense CP radiation is achieved using the same four modes. The unified antenna structure, which allows switching between dual-band and triband dual-sense CP radiation states within the same configuration, is realized by manipulating the modes. This is accomplished by simply adjusting the position of the shorting pin. The measurement results have confirmed the effectiveness of this method, with the multiband dual-sense CP antennas achieving a 3 dB axial ratio bandwidth of 1.14% –2.31%.