Evaluation of narrowband coupling techniques against frequency variation

This article presents the design of two couplers using a simple stub, one in series and one in parallel, and a coupler design using a quarter lambda section. The aim is to compare the behavior of the frequency variation for a passing bandwidth through the transmission line, considering their respective variation in the lengths in which the couplers are located and the distances of the stubs. In such a way, that each design can be compared and analyzed to determine which of all three is the best coupler in terms of low impacts due to a passing bandwidth. For this, each design is made with the help of the software Amanogawa (Amanogawa.com, s. f.) and by means of the Smith chart. Similarly, the simulation of each one is carried out and through a physical experiment, stub in parallel, the results obtained are corroborated. Observing that the parallel stub method proves to be the most optimal, in terms of implementation and acceptance of a higher bandwidth pass-through variation.