Design of broad-band lumped-element baluns with inherent impedance transformation
Journal article, 2004

This paper reports on a novel lumped balun topology, the second-order lattice balun, with broad-band performance. The design is based on synthetic transmission lines operating as impedance transformers. The characteristic impedance of the synthetic transmission lines may be chosen to obtain inherent impedance transformation. An analytical investigation results in closed formulas for optimum performance over a given bandwidth. It is shown that it is possible to design for equal ripple in amplitude balance and input reflection coefficient. The phase balance is theoretically perfect over the entire bandwidth. The concept is experimentally validated by a 1-GHz prototype fabricated with surface mounted chip components. It exhibits an amplitude balance better than 0.5 dB and a phase balance better than +or-8 degrees over an octave bandwidth. The effective area of the prototype is 7 * 9 mm/sup 2/

network synthesis

network topology

transmission line theory

MMIC

baluns

impedance convertors

lumped parameter networks

Author

Dan Kuylenstierna

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Peter Linner

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

IEEE Transactions on Microwave Theory and Techniques

0018-9480 (ISSN)

Vol. 52 12 2739-45

Subject Categories

Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1109/TMTT.2004.838305

More information

Created

10/6/2017