LNA and mixer designs for RF front-ends

In this thesis, possible LNA and mixer circuits suitable for RF front-ends of wireless receivers with direct conversion modulation are proposed. The main objectives in each design were optimized power consumption, small chip area and low supply voltage.;For a flexible LNA design to be accepted in industry, it is desirable to include the ESD diodes, pads, layout and package parasitics. This thesis also examines the impact of these parasitics on the gain and noise figure of a cascode CMOS LNA. A CMOS LNA integrated circuit is developed based on this analysis for GPS applications.;Two mixers were designed and developed for integrated receiver RF front-ends. The first mixer is an ultra-low power active bulk driven mixer. The presented mixer in this work is an excellent candidate for RF front-ends with low supply voltage for Bluetooth applications. Because it occupies a small area of 0.0225 mm2 on chip and has a wide band IF output, this mixer is suitable for many integrated receivers that require IF output in range of 500 kHz- 100 MHz.;This research also presents a novel active double balanced mixer using a combination of active load and current bleeding to achieve high conversion gain of 22 dB and low noise figure of 8.5 dB. The implemented CMOS double balanced mixer is introduced as a RF front-end block for GPS applications.;A single LNA capable of providing a wide band power gain without using extra inductor was proposed in this thesis. The proposed LNA can save area and design effort, compared with LNAs with double tanks or RF front-ends with two cascaded LNAs. The bipolar wide band LNA is introduced as a RF front-end block for IEEE 802.11a standard. This LNA features a power gain of 11.13 dB, a high reverse isolation of -38.47 dB and is suitable for receivers with direct conversion modulation.