Reconfigurable Circuit Design and Load Modulation Techniques for 5G Coexistence with Weather Radiometry
mm-Wave frequency bands for the next generation 5G systems concern weather forecasters as they are close to bands of interest for passive radiometers. Interference risks can be mitigated by reconfigurable RF hardware provided high performance is maintained despite the necessary tuning mechanisms. Ensuring successful co-existence of such systems requires fast real-time impedance control and reconfiguration. Although some hardware architectures exist in the 1–10GHz range, they do not scale favorably in the mm-wave range due to high losses and poor performance. In this talk we will demonstrate a new class of solutions based on high-quality resonant impedance networks that can simultaneously achieve high-performance, wide tuning range, and fast reconfiguration in the mm-wave range. Critical trade-offs including number of tuning elements, impedance coverage, loss, and reconfiguration speed will be discussed. Both theoretical and experimental results will be presented. Additionally, a new quadrature-coupled load modulation approach will be discussed that can provide intrinsic reconfigurability for multi-band multi-mode operations without relying on extra varactors and/or switches. This will be compared to a traditional Doherty implementation, which has limited bandwidth and dynamic range, and is highly sensitive to antenna mismatch which is inevitable in emerging 5G systems due to the beamforming and steering using large antenna arrays, also known as massive MIMO. Design examples will be presented with unprecedented bandwidth, efficiency, power back-off range, and strong resilience to antenna mismatch, which are highly demanded for 5G-and-beyond communications.