Design and Packaging Analysis of a Ku Band High Gain GaAs MMIC LNA

A Ku band high gain low noise amplifier (LNA) designed using the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.15 \mu ~\mathrm{m}$</tex> GaAs pHEMT process is presented in this paper. Three types of connections between the MMIC (monolithic microwave integrated circuit) LNA chip and the input port are compared in terms of their loss and noise contribution. To achieve a very low noise figure, a gold bonding wire is used as a series matching inductor in the input matching circuit due to its minimal loss. The tolerance of the LNA related to the wire shape variation is also studied. EM-circuit co-simulation analysis of the LNA package is also carried out to detect higher mode resonances before fabrication. This MMIC LNA is designed, fabricated and packaged in a gold-plated chassis. The whole LNA module is measured through a coaxial system from 9 to 18 GHz. The gain ranges from 35 to 39.5 dB and the noise figure is lower than 1.75 dB. By de-embedding the noise contribution of the RF connector, the noise figure of the MMIC chip is lower than <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1.26~ d B}$</tex> from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{9}$</tex> to 18 GHz. Compared with other reported LNAs using a similar GaAs MMIC process in similar frequency bands, the presented LNA chip and module shows superior noise figure at room temperature.