Design And Study Of Wideband Transition Between Coplanar Waveguide And Broadside Coupled Stripline

Wideband transition between coplanar waveguide (CPW) and broadside coupled strip line(BCS) with its related theory and technology is proposed and studied. Compared with otherstudies in this field, this transition in this thesis is compact, has wide bandwidth and simplestructure and many other advantages.In the beginning part, the thesis proposes an equivalent circuit model for a very simpletransition. In order to verify the correctness of the equivalent circuit model, the transmissionparameters which come out from the full-wave analysis and from the equivalent circuit modelwere compared in this paper and which can be very helpful to build theories and theoreticalfoundation for designing high-performance transition between coplanar waveguide andbroadside coupled strip line.Then, the thesis find a way to improve the bandwidth, reduce the insertion loss and optimizethe structure of the transition. Analysis is given step-by-step to verify the correctness of theoptimization method through software simulations and experiment measurements.One kind transition with good performance is proposed and studied. The center conductor ofthe CPW is designed to linearly transit to one arm of the BCS, and the ground plane is coupledand then transited to another arm of the BCS via a Y-shaped stub. By introducing such a simplestructure, the E-field of CPW is gradually changed to that of BCS within a wide bandwidth.Parametric study of the transition is carried out first. Then, four different back-to-back transitionsare simulated, fabricated and measured. It is shown that maximum operation bandwidth from1.16GHz to12.02GHz for return loss larger than10dB and insertion loss lower than2.4dB canbe obtained.