Six Layers Stripline RF-Invisible Balun

Victor Taracila¹, Aleksey Zemskov¹, Vijayanand Alagappan¹, Fraser Robb¹

In the well-known preamplifier decoupling technique, a low input impedance preamplifier in series with an inductor attached to the matching capacitor is utilized. One of the problem of this design is the inductors stray field and preamplifiers ground disturbance. When using a balun in front of the preamplifier, the transmission line from which the balun is composed creates the needed inductance. Also, providing high impedance on the outer shield of the balun, amplifier ground is kept unperturbed. In this work we present the RF-invisible balun based on double spiral inductor shape and its PCB implementation.