Beam Switching Antenna Based on a Reconfigurable Cascaded Feeding Network

In this paper, a beam switching antenna (BSA) based on a reconfigurable cascaded feeding network (RCFN) is presented. The RCFN is engineered by cascading several varactor-loaded quasi-lumped couplers (QLCs). As the output port of the RCFN, the coupled port of every QLC is connected to an endfire radiator. BSAs based on two types of RCFN, the open-loop RCFN and closed-loop RCFN, are designed, simulated, and measured. The open-loop design features flexible beam switching strategies with the dynamic control of operation modes allocating the input power to the intended radiator(s), and single-/multibeam switching is achieved. In the case of the closed-loop RCFN, a power-recycling circuit is introduced to improve the efficiency of the single-beam switching mode of the BSA. Measured results show that the BSA operating in single-beam mode is able to radiate six switched beams each with a 3 dB beamwidth of 60°, covering 360° in the azimuth plane. The return losses and gain fluctuation of both prototypes are better than 15 dB and less than 1 dB, respectively. The corresponding experiments agree well with both the theoretical analysis and the simulation results.