New Model Of Microstrip Non-symmetrical Double Step Discontinuties

The continuous increase in working frequency and the widespread diffusion of monolithic microwave integrated circuits requires the development of models based on a wide-band approach and not just on a quasi-static approximation that limits their validity at a much lower frequency range. In recent papers [1,2], an equivalent circuit has been presented for the double-step microstrip discontinuity for the symmetric case; on the other hand, during MMIC design process, layout constraints often force to consider the asymmetric discontinuity. In this paper the non-symmetric case is considered, and a more general equivalent circuit is derived. A planar electromagnetic approach, which intrinsically insures broadband validity, has been utilized, obtaining a circuit whose lumped elements are frequency independent . A comparison with experimental data confirms the effectiveness of the proposed model.