Ahmad Yarahmadi - Dept. electrical and computer engineering Tarbiat Modares University Tehran, Iran
Abumoslem Jannesari - Dept. electrical and computer engineering Tarbiat Modares University Tehran, Iran

This paper presents a low noise amplifier (LNA) in TSMC 0.18μm CMOS technology for X band applications. The amplifier has two CMOS inverter cells, cascaded together to achieve a flat and high enough gain. Furthermore, the first inverter cell should provide wideband input impedance matching. For this purpose, resistive shunt feedback is applied to the both inverters. By using this technique, the LNA will be self-biased and it does not need any additional bias circuit. A gate peaking technique is also applied to the both inverters to compensate the parasitic capacitance of MOS transistors at high frequencies. The proposed LNA delivers a maximum power gain of 13dB with a gain flatness of 1.35dB within the interested band. The circuit exhibits good noise performance and the noise figure (NF) is 2.06< NF <3.28. The LNA consumes 8.2mW from a 1.8V supply while providing IIP3 of about -10dBm.

CMOS inverter cell; resistive feedback technique; gate peaking technique; self-biased circuit; X band applications