Multiband High-Linearity Front-end Receivers for Wireless Applications

In this paper, a modified front-end receiver configuration, which consists of an LNA and mixer suitable for zero-IF or low-IF receivers, is presented. The idea is to achieve a better linearity for receivers by combining circuit and system level solutions. Three circuit topologies, two in bipolar and one in CMOS technology, are presented in this paper with their simulation results. One of the bipolar topologies has been implemented and measurement results are presented. An IIP₃ of up to +0.6 dBm of a combined bipolar LNA and mixer is achieved, depending on frequency of interest and with an acceptable noise figure performance at a current consumption of less than 13 mA from 5 V supply voltage in one circuit and 3 V supply voltage in the other one. An IIP₃ up to +5 dBm is achieved for the CMOS topology at a lower overall gain and acceptable noise figure (14.4 mA and 3 V). All circuits presented in this paper are wideband circuits, suitable for area-efficient multiband receivers.     

A wide-band RF front-end for multiband multistandard high-linearity low-IF wireless receivers

A wide-band radio-frequency (RF) front-end is designed with a balanced combined low-noise amplifier and a switching mixer (a low-noise converter) in an RF Si-bipolar process with an f/sub T/ of 25 GHz. The circuit achieves 20-dB conversion gain, higher than -4.5-dBm RF-to-IF IIP/sub 3/ (+15.5-dBm OIP/sub 3/) and less than 3.8-dB double-side-band noise figure in 900-MHz (e.g., GSM) and 1.9-GHz (e.g., WCDMA) frequency bands. The -1-dB compression point is -20 dBm at 13-mA DC current consumption from a single 5-V supply. The local-oscillator leakage to the input is less than -56 dBm in the 900-MHz band and less than -63 dBm in the 1.9-GHz band. The -3-dB bandwidth of the amplifier is larger than 3 GHz and a wide-band matching at the input with -10 to -41-dB S/sub 11/ is achieved in the frequency bands of interest by applying a dual-loop wide-band active feedback. The die area is 0.69 /spl times/ 0.9 mm/sup 2/. The circuit is suitable for area-efficient multiband multistandard low-IF receivers.