Probe-Fed Miniature Circularly Polarized (CP) Patch Antenna Loaded with Mush-Room Meta-Substrate

This paper reports a probe-fed miniature circularly polarized (CP) patch antenna loaded with mush-room meta-substrate. The mush-room structures are designed in a low index host substrate. Compared with that of conventional patch antenna, the resonant frequency of the meta-antenna is reduced, indicating a miniature prototype. The CP mode is realized by cutting off two triangle corners from the square patch exciting two orthogonal linearly polarized modes with phase difference of 90 degree. A proof antenna is simulated to verify the design. Numerical results show that the electrical patch size for the proof antenna is reduced to $0.19\lambda_{0}$ . The impedance bandwidth of the proposed antenna is 3.76%. The simulated antenna gain is 4.7dBi and radiation efficiency is $n=87\%$ . The radiation patterns are also shown that the boresight cross-polar levels are all below - 15dB. The bandwidth for the 3dB CP axial ratio is 0.9%. The miniature CP antenna in this communication is easy to fabricate using the low cost printed board circuit technology and can be used in wireless communication and handset devices in future.