Research On Broadband Multi-Beam And Multi-Polarization Feeding Network

The feeding networks of antenna array are key components, which could achieve functions of multi-beam, multi-polarization, frequency agility, single pulse and beam scanning. It is widely used in mobile communication system, radar system, satellite communication system and electronic countermeasure system, especially for massive multiple-input multiple-output mobile communication system. For the application of the systems above, it is urgent to research the multi-beam and multi-polarization feeding network of antenna array. This dissertation is organized as follow:1. A dualband Butler multi-beam feeding network working on 2.4/3.5GHz is built, using dualband directional couplers and 45°phase shifters with microstrip structure. The multi-layer structure avoids the cross-junction in traditional Butler network, leading to lower loss and smaller areas of Butler network.2. A broadband Butler multi-beam feeding network working on 2GHz to 4GHz are designed, applying broadband directional couplers and 45°phase shifters with microstrip broadside coupling. It realizes the miniaturization design of multi-beam feeding network.3. Based on broadside coupling, a broadband coplanar waveguide three holes coupling directional coupler is designed, which works in ultra-wide band. Then, a broadband multi-polarization feeding network is designed using the broadband directional coupler, a multi-stage cascade Wilkinson power divider and a SP4T switch. The multi-polarization feeding network could offer four polarizations, namely, vertical polarization,45°linear polarization, left-hand circular polarization and right-hand circular polarization, using a dual-polarized antenna cell.