Q-Band LNA-Antenna Co-Design: Exploiting Antenna Matching for System Noise Figure Optimization

This paper presents a novel approach to low noise amplifier (LNA)-antenna co-design in the Q-band frequency range, leveraging the antenna as an integral part of the LNA matching network to achieve broadband noise figure improvement.Unlike conventional designs, the proposed LNA does not include a 50Ω input matching network, allowing direct access to the complex frequency-dependent impedance (Γopt) associated with the LNA’s minimal noise figure (NFmin). The antenna input impedance is optimized to match the LNA for minimal noise contribution, effectively enhancing system performance. Noise figure measurements of the active antenna prototype confirm the achievement of NFmin, ranging from 1.9 to 1.4 dB within the 35 to 40 GHz frequency band. Additionally, the receiver system demonstrates a gain of 14.5 dB and a noise figure below 3.6 dB across the operating frequency range. These results validate the effectiveness of the proposed co-design approach in reducing noise while maintaining high gain, making it a promising solution for next-generation millimeter-wave communication and sensing applications.