Compact Symmetric Quarter Mode Substrate Integrated Waveguide (QMSIW) Antenna

A compact symmetrical Quarter Mode Substrate Integrated Waveguide (QMSIW) based antenna with improved performance in terms of impedance matching, radiation efficiency, gain and the reduced cross-polarization level for C-band application is proposed in this paper. In this design, two circular ring slots are inserted to achieve circular polarization (CP) and four open circuit stubs in used at four corners to improve the impedance matching. The proposed antenna generates TE
₂₀₂
mode and is designed for circular polarization. The measured results show that the impedance bandwidth (|S
₁₁
| <; -10 dB) of 6.245-6.635 GHz is 6.07% and the 3-dB axial ratio bandwidth of 6.457-6.575 GHz for the CP. The measured maximum gain of the proposed antenna is 6.93 dBi. The antenna has achieved a radiation efficiency of 90.01% with respect to the resonate frequency at 6.425 GHz. The measured results are quite in agreement with the simulation results. The performance of the antenna is found to be much better than the similar kind of antenna reported in literature.