Lumped element balun with inherent complex impedance transformation
Paper in proceedings, 2017

A novel lumped design approach for complex impedance transforming baluns is presented in this paper. It is shown that a relaxation of symmetry in the T-networks of the out-of-phase-compensated-power-splitter enables complex impedance transformation. Design equations are analytically derived for a total of 4 component values, of which 2 values depend upon the 2 other, which are free variables. The two free component values are used independently for adjustment of input reflection loss, further keeping the balance parameter maximally flat and independent of the load impedance. For Q-values of source and load, not being excessively high, the balun can be realized with only 8 components. A demonstrator is fabricated, transforming 26.9 + j11.1 Ω to 73.8 + j38.6 Ω. An amplitude balance of ±0.7 dB and phase balance better than ±5° is achieved over a 20 % bandwidth. The return loss is higher than 20 dB.

Author

Markus Frank

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Mattias Thorsell

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Peter Enoksson

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

IEEE MTT-S International Microwave Symposium Digest

0149645X (ISSN)

1285-1288 8058843

Areas of Advance

Information and Communication Technology

Subject Categories

Telecommunications

DOI

10.1109/MWSYM.2017.8058843

ISBN

978-1-5090-6360-4

More information

Latest update

9/21/2018