A Multistandard RF Front-End Using Varactor Controlled Tunable Interstage Matching Network

A multistandard RF front-end using a tunable interstage matching network is designed in 0.25 μm CMOS technology. It consists of a wideband LNA, interstage matching network, and a Gilbert-cell mixer. Tunability of the interstage matching can be obtained by a MOS varactor. It can change tuning frequency by controlling capacitance of varactor. Gain can be flattened over whole target band by the proposed interstage matching. Designed RF front-end has homogeneous performance from 1.8 to 2.4 GHz. It can be used for 3G wireless communications, mobile internet, and WLAN applications such as IEEE 802.11b/g.