Design and analysis of hybrid couplers using lumped elements and microstrip topology

In this paper, two dual hybrid couplers using artificial transmission lines are designed and analyzed. The artificial transmission lines are implemented in microstrip technology and using lumped elements to obtain the left-handed behavior. A detailed analysis of the real-life implementation of the couplers considering both the effects of microstrip lines and lumped elements is described, comparing the results of the two proposed couplers. The influence of the standardized values of the lumped elements and their finite quality factor is investigated when implementing the two dual hybrid couplers. Also, the phase difference introduced by the access microstrip transmission lines is investigated and ways of compensating it are discussed in correlation to the overall frequency response of the couplers.