Printed-Probe E-plane coupler design and simulation using the TLM (Transmission Line Modeling) method

This work presents an implementation procedure for the E-plane printed-probe coupler. This coupler can be obtained with an array of printed capacitive elements, mounted on the E plane of a waveguide. The design of a multiprobe directional coupler starts by the performance analysis or a single probe, with variable depth and width. Using the tridimensional TLM (Transmission Line Matrix Method), a database of results with probes of fixed width and variable depth and fixed depth and variable width is generated. Using these results and a simple design procedure a multi-element array was designed, where the coupling coefficient of each element is proportional to the coefficients of the Chebyshev polynomial. Using these results, a simulation of the 5-element Chebyshev array was performed using the three-dimensional TLM. The simulation difficulties are discussed and the results are shown.