A novel compact balun structure for multilayer MMICs

Abstract

A novel compact MMIC balun and its design methodology has been developed, and turns out to combine the good balance of a MARCHAND-type balun with the compactness of a MMIC transmission line transformer. Analysis using accurate quasi-static as well as parallel independent full-wave simulation shows good performance. Application of this component is seen for example in microwave and RF frequency conversion and power amplifiers.

Improved compaction of multilayer MMIC/MCM baluns using lumped element compensation

“…Very recently, however, compact balun structures have been demonstrated together with a suitable design procedure [3] which are essentially wound-up transmission line transformers (TILTS) using a second wound-up TL-structure for compensation, thus resulting in excellent broadband balance [4]. This latter approach, for example, allows to design cost-saving balun structures in MCM technology on thick silicon [5] even for wireless communication applications in the low-end --GHz region [6].…”

“…The space consumption of such a 1.9 GHz balun with 1:4 impedance transformation is about 2.5mm2, for example. This paper starts from the fact that many wireless communication subsystems do not need the full potential of broad bandwidth and excellent balance to halving the space requirements leads to poor electrical performance, particularly to poor balance of the output signal [4]. The idea is, therefore, to replace the TLtype compensation structure by a lumped and much more compact impedance representation Z(f) as indicated in Fig.…”

“…In order to look into the details of the impedance representation required, the same field-theory based quasi-TEM multilayer simulation tool already applied in [3], [4], with an earlier version described in [7], [8] has been used. This tool has been verified repeatedly in the past by comparisons with measurements performed on similar components and with 2.5D EM results generated by another commercial simulator [7] , [8].…”