A 3–5 GHz Frequency-Tunable Receiver Frontend for Multiband Applications

In this letter, a fully integrated receiver frontend which is composed of a low-noise amplifier and a down-conversion mixer is presented for multiband applications. Different from conventional concurrent or switched-type architectures, the proposed circuit uses varactors for the frequency tuning. In addition, broadband techniques are also employed to maximize the operating frequency range and to enhance the circuit performance. Using a standard 0.18 mum CMOS technology, a 3-5 GHz receiver frontend is implemented for demonstration. With a LO power of 3 dBm and an IF frequency of 10 MHz, the circuit exhibits a conversion gain of 22.2 plusmn2.4 dB while the IIP3 and noise figure are better than -6 dBm and 17 dB, respectively, within the entire frequency range. Operated at a supply voltage of 2 V, the receiver consumes a dc power of 16 mW.