Design of compact highly matched broadband balanced low‐noise amplifier at X‐band using CRLH transmission lines

Abstract

This article presents broadband balanced low‐noise amplifier (LNA) operating at X‐band, which uses composite right/left‐handed (CRLH) transmission lines as input–output matching networks. Proposed LNA eliminates lumped DC‐blocking capacitors and is combined with a hybrid coupler to achieve better stability and matching. Presented CRLH matching technique enhances the matching quality, reduces the overall size and considerably improves the bandwidth and noise performance. The matrix analysis of the CRLH structure is provided to determine the exact dimension of microstrip lines for the highest stable gain and the lowest noise figure (NF). The LNA structure uses a HJFET technology as an active device, which is simulated using an ADS momentum and small‐signal scattering parameters provided by the manufacturer. This LNA offers an improved impedance matching and measured the 20 dB S11 band‐width of 16% (8.3–9.7GHz), which is in good agreement with simulation. Total area occupied by the fabricated LNA is only 1.7λ0×0.9λ0@ 8.3GHz. The LNA also provides <1.8 dB NF based on the IEEE standard temperature (16.85 Celsius), and 1 dB gain flatness throughout the entire band along with a 1 dB compression point of −1 dBm and an output third point intercept point of 19.5 dBm. The proposed CRLH‐based LNA can be a good candidate for compact receivers and sensors.