Assembled dual-band broadband quadrifilar helix antennas with compact power divider networks for CNSS application

Assembled dual-band quadrifilar helix antennas (QHAs) are proposed for applications in Compass Navigation Satellite System (CNSS) of China. The assembled CNSS antennas proposed are designed specifically to meet the requirements of the system: Duplex communication service on two frequency bands (1.615 GHz and 2.492 GHz); Broad beamwitdh on radiation pattern and broad bandwidth for circularly polarization (CP) applications. In this paper, the structure of assembled CNSS QHAs is demonstrated first, which comprises of emitting and receiving QHAs with novel compact power divider networks. Then the method to control the radiation pattern of QHAs is analyzed. Moreover, the design principle of the compact power divider network to achieve broadband application is presented. In the end, the antenna was fabricated and measured. Experimental results show that the proposed assembled CNSS dual-band QHAs exhibit duplex operation, broad 3 dB beamwidth (> 180°), and broad 10 dB return loss bandwidth (emitting antenna 39%; receiving antenna 28%). In addition, the axial ratio is less than 1.5 on two frequency bands of the system (Uplink: 1615.68±7 MHz; Downlink: 2491.75±15 MHz).