A co-design study of low noise amplifier and band-pass filter

Abstract

In this paper, the traditional 50Ω interface between the LNA (low-noise amplifier) and the BPF (band-pass filter) is removed, and a co-designed LNA-BPF is presented. The BPF is used to suppress the harmonics and acts as the matching network of LNA. The measured results show, at 2.5GHz, the co-designed LNA-filter achieves a voltage gain of 15.04 dB, a noise figure of 3.9 dB, 3rd harmonic suppression of 66.17dB and PI1dB of -13dBm. Compared with traditional versions with 50Ω interfaces, the co-designed version obtains a large voltage gain, better PI1dB and 3rd harmonic suppression and is more compact. Good agreement between the measured and simulated results is achieved.