Low-Noise High-Linearity Blocker-Tolerant Receivers: The Next Mile Toward FR3 6G

FR3 covering 7–24GHz is emerging as a strong candidate for 6G wireless communications. Commonly referred to as the Golden Band, FR3 can provide a precious balance between the wide coverage of FR1 and the high data-rate of FR2. Therefore, receivers with low noise, high linearity, and resilience to blockers are essential for next-generation mobile communications. Mixer-first receivers, widely recognized as a leading blocker-tolerant architecture, have attracted extensive interest recently, but mostly have been implemented in sub-6GHz bands. Only a limited number of mm-wave mixer-first receivers have been presented, but with modest performance and limited experimental validation. In this presentation, we review state-of-the-art circuit techniques and architectures for mixer-first receivers and evaluate their potentials and challenges for operation in the FR3 band. The presentation starts with a brief yet in-depth overview of the mixer-first receiver fundamentals and their operation in the presence of blockers. We then discuss techniques for linearity improvement, noise cancellation, and harmonic rejection. This is followed by recent advances in capacitor stacking to provide passive voltage gain, an input transformer to perform impedance transformation and voltage amplification, and selectivity enhancement. Finally, we address the multi-phase clock generation for mixer-first receivers, a challenge that was trivial at sub-6GHz but becomes increasingly critical for FR3.