Lumped and distributed lattice-type LC-baluns

Abstract

This paper presents two balun circuits derived from the lumped Lattice-type LC-balun. First the lumped LC-balun bridge elements are substituted by microstrip lines. This results in an improved performance at the 2nd and 3rd harmonic frequency for RF power amplifier output baluns. Secondly, the lumped Lattice-type LC-balun is extended to a dual band balun. Independent impedance transformation and balun conversion can be done at two different frequencies. The design equations are derived.