Compact monolithic integrated resistive mixers with low distortion for HIPERLAN

Abstract

Three ultra-compact low-cost mixers, using either a single enhancement, depletion, or deep-depletion FET are presented and compared. They are designed for HIPERLAN and 802.11a receivers with radio and intermediate frequencies around 5.2 and 0.95 GHz, respectively. An improved MESFET large-signal model has been used to allow efficient optimizations of the circuits. The fully integrated mixers have been fabricated using a commercial 0.6-/spl mu/m GaAs MESFET process and require a total chip area of only 0.5 mm/sup 2/. With an ultra-low local-oscillator (LO) power of -10 dBm, the enhancement FET mixer achieves a -4.7 dBm 1-dB input compression point, a 12.6-dB conversion loss, and a 13-dB noise figure. At a low LO power of -2.5 dBm, excellent dynamic properties are obtained for the depletion FET mixer with 2.6-dBm 1-dB input compression point, 8.3-dB conversion loss, and 8.8-dB noise figure. State-of the-art performances with 16-dBm 1-dB input compression point, 5.5-dB conversion loss, and 6.5-dB noise figure are reached for the deep depletion FET mixer at 10-dBm LO power.