Projeto de Circuito Beamformer para Antenas com Dupla Polarização Circular

This paper presents the design of a beamformer circuit for dual circularly polarized antennas composed of four sequentially rotated radiators. The beamformer operates over the L band, and its architecture has two 180-deg hybrid couplers, one 90-deg hybrid coupler, and two low-noise amplifiers. Commercial components are selected to build the circuit prototype, and its scattering parameters are measured. The prototype is used to feed a sinuous antenna designed to receive GNSS signals. The antenna measurements show that the broadside axial ratio is below 2.25 dB from 1 to 2 GHz, thus validating the beamformer operation.