A suspended capacitively coupled feed broadband circularly polarized microstrip antenna

A capacitance-coupled circularly polarized microstrip antenna is designed to solve the problem of bandwidth widening and off-center pattern when the feed is off-center. The antenna radiation patch realizes circular polarization through a pair of slots and truncating patch corners. A metal post is introduced in the centre of the patch to connect with the floor to broaden the bandwidth of the antenna and correct the deviation of the direction pattern. The simulation results show that the antenna |S11| < -10dB bandwidth of 1.85-2.48 GHz (31%), 3dB Axial Ratio bandwidth of 2.25-2.45 GHz, gain up to 8.6 dBi. The antenna is made of aluminium, which is simple and low cost.