Broadband chokes for Bias Tee applications: how to successfully apply a DC bias onto an RF line

The demand for increased bandwidth in data communication is continually increasing, RF signal integrity has become a major design concern. In broadband bias applications, most inductors do not cover enough impedance bandwidth. By putting three or four inductors in series, bandwidth can be increased, but DC losses and filter complexity increase. A broadband bias choke can provide wide bandwidth in a single inductor package. This paper discusses the proper use of broadband chokes in bias tees and critical design considerations including frequency range, DC resistance, current requirements, products size and cost.