Group delay adjuster using resonance circuit with varactor diode

This paper presents a method to control group delay using resonance circuit. The group delay adjuster (GDA) which can control signal group delay time comprises a variable capacitance and a variable virtual inductor. These are coupled in parallel at a node and also controlled by two bias voltages respectively. A variable virtual inductor has realized a transmission line terminated a variable capacitor. When the proposed GDA is fabricated on cellular base-station transmitting band (869-894MHz), a group delay variation range of the fabricated GDA is about 1ns.