A center-fed BeiDou antenna with zero phase center

A center-fed circularly polarized (CP) antenna with zero phase center is proposed in this paper. The proposed antenna can work in the BeiDou satellite navigation system (CNSS) B1-band (1561.098 ± 2.046MHz), and it has been fabricated and tested. The center-fed antenna uses a square microstrip patch with four slots, and an annular slot is embedded into the patch to achieve the CP radiation. The structure is symmetric and it has a good zero-phase center. The measured -10dB impedance bandwidth is 116.5MHz, 7.46%, and the simulated 3dB axial ratio bandwidth is 26.05MHz, 1.67%. The peak radiation gain is 4.32dB at the B1-band, and it has a good upward radiation pattern. The measured results agree well with the simulation ones, that verifies the correctness of the theoretical analysis.