Q-based design method for T network impedance matching

Impedance matching using passive network is very important in the design of RF and microwave circuits to achieve maximum power transfer, minimum reflection, and adequate harmonic rejection. This paper investigates the T network impedance matching analytically. A practical guide is provided for systematic network design based on the desired harmonic rejection specification. Expressions of the frequency response and harmonic rejection in term of the loaded Q are established. The limits of the network are analytically demonstrated. It is shown that the third harmonic rejection is about 12 dB higher than second harmonic rejection provided that the loaded Q is larger than twice the minimum Q.