Redes de conformación de Haz (Fase I)

Abstract

This document presents the design of two types of beamforming networks used as constrained feed networks: Butler matrix and a 4-way power divider with broadband phase shifters. The methodology is developed around the need to obtain differential phases in a specific bandwidth with central fixed frequency of 2.45 GHz, reminding that the total bandwidth has both, power and phase performances; phase shifters and hybrids are presented as circuits with transmission lines to express an analytical model, deducing convenient design strategies. Any network similar to the beamforming networks studied in this project can be divided into stages, allowing to define a phase diagram; this is considered a design and diagnostic tool in the generation of phase and power bandwidths. The analytical models and the phase diagram let the proposed design methodology to be efficient and the network to generate total bandwidths. Modified geometries for the different devices are proposed, with the exception of the Wilkinson divider. In general, branches, open stubs or short stubs are used. Thus, the resonances are increased improving the performance in power; it also happens that the phase is modified in such a way that it is possible to maintain differential phases in a range of frequencies. A variation in the number of stubs is used; it is also presented geometries of multiple branches for quadrature hybrids and crossover circuits, in order to obtain power bandwidths similar to those of phase. After achieving total bandwidths greater than 25%, a butler matrix of order two and another of order three is designed, as well as the 4-way divider network with phase shifters. In the case of the butler matrix of order three, a geometry is chosen avoiding the crossover circuits. In all cases, prototypes are made and characterized. The study of phase shifters and directional couplers based on analytical models allows the use of geometries formed by stubs and branches as a strategy that in addition with a phase diagram let design beamforming networks with total bandwidths greater than 24%.