Symmetric baluns and isolation techniques

摘要

Wideband balun having good performance characteristics for use in feeding differential antenna elements in array antennas, balanced amplifier circuits and other applications is described. Also described is a common mode isolation circuit suitable for integration with the balun.

主权项

1. A balun comprises:
first and second substrates, each of the first and second substrates having a first surface having a ground plane disposed thereon and having a plurality of conductive transmission lines disposed on a second surface thereof; and a center dielectric layer having a conductor provided along a center thereof so as to form a double offset stripline with at least some of the plurality of conductive transmission lines disposed on the second surface of the first and second substrates, said center dielectric layer disposed between the second surfaces of said first and second substrates such that said center dielectric layer dielectrically spaces the plurality of conductive transmission lines disposed on the respective second surfaces of said first and second substrates by an amount which is substantially symmetric about the conductor provided in said center dielectric layer and wherein, when disposed proximate each other, the plurality of conductive transmission lines disposed on the respective second surfaces of said first and second substrates substrate conductors form a symmetric, stripline Marchand balun.