Balun comprising stepped transitions between balance and unbalance connections, where the stepped transitions include ground rings of differing lengths connected by caged vias

Abstract

An example balun includes a center conductor that passes through a printed wiring board having multiple dielectric layers and cage vias arranged relative to the center conductor. The cage vias include a first set of cage vias that extend between an unbalanced connection to the balun and a balanced connection to the balun. The first set of cage vias are part of a first circular arc and are connected to electrical ground through a first ground ring. The cage vias include a second set of cage vias that extend from the unbalanced connection part-way through the printed wiring board. The second set of cage vias are part of a second circular arc and are connected to the electrical ground through a second ground ring. The second circular arc is longer than the first circular arc.