A SiGe BiCMOS Bypass Low-Noise Amplifier for X-Band Phased Array RADARs

Abstract

This paper presents a bypass low noise amplifier (LNA) for X-band phased array applications in $\pmb{0.25\mu \text{m SiGe}}$ BiCMOS technology. The trade-off between gain and bypass modes is considered to achieve high gain as well as low noise figure for gain mode while maintaining reasonable insertion loss with high power handling capability in bypass mode. In gain mode, the LNA achieves a measured gain of 17-14.2 dB and a noise figure of 1.75-1.95 dB over the 8–12 GHz band while consuming 27.4mW of DC-power. The measured input-referred I-dB compression point $\pmb{(\text{IP}_{1\text{dB}})}$ is -3.9 $\mathbf{dBm}$ at 10 GHz. When operating in bypass mode, the measured insertion loss is 6.5-5.95 dB over the entire X-band with the measured $\mathbf{IP}_{1\mathbf{dB}}$ of 15.1 dBm at 10 GHz, and it dissipates only $1\mu \mathbf{W}$ power. Thanks to the bypassing technique, an increase of about 19 dB is achieved for $\mathbf{IP}_{1\mathbf{dB}}$ in bypass mode compare to the gain mode. The measured return losses are better than 10 dB for both operating modes over whole X-band. The effective chip area excluding the pads is 0.3 mnr’.