GENERALIZED ANALYTICAL DESIGN OF BROADBAND PLANAR BALUNS BASED ON WIRE-BONDED MULTICONDUCTOR TRANSMISSION LINES

A novel generalized design procedure of broadband planar baluns based on wire-bonded multiconductor transmission lines (MTL) is presented hereby based on analytical equations. The proposed balun consists of two parts. The first one is an in-phase power divider, which equally splits the input power through its two outputs. The later are two MTLs with wire bonding between alternate conductors configured to introduce +90 and -90 degrees phase shift respectively, so that the balanced output signal has a 180 degree phase difference. In that sense, new closed-form design equations in order to calculate the design parameters of both multiconductor elements are obtained. These equations allow the proper dimensions of both MTLs to be computed irrespective of both the number of conductors and the coupling factor, and therefore, to determine the performance of the balun. The design procedure for wire-bonded MTL baluns has been assessed by means of full-wave electromagnetic simulations and by experimental work. In addition, the very good agreement between the theoretical results and measurements makes possible to define a time-saving design methodology.