MEMS technologist Nanusens is putting its RF digitally tunable capacitors (DTCs) to new use in RF front ends to help 5G and 6G take off. UK-based Nanusens recently announced a novel MEMS-within-CMOS solution for RF front-end design to address many of the challenges of 6G.
As the global 5G rollout continues, researchers and engineers are already grappling with the next generation of wireless communication. 6G is looming around the corner, promising unprecedented data rates, ultra-low latency, and the ability to support a massive number of connected devices. However, these advancements have significant technical hurdles, particularly in RF front-end design.
The higher frequency bands required for 6G necessitate novel approaches to antenna design and signal processing—and Nanusens aims to deliver such an approach with its new solution.
Nanusens' MEMS-Within-CMOS Technology
Central to Nanusens' new solution is RF digitally tunable capacitors (DTCs), which were developed using nanoscale MEMS structures integrated within standard CMOS layers. These DTCs offer significant advantages over existing solutions, including superior linearity for minimal distortion, increased power efficiency, and a consistently high Q factor that maintains performance even in upper-frequency bands.
DTC Q-factor versus frequency.
By replacing conventional tunable capacitors with DTCs, Nanusens addresses a key hurdle in 6G development: the need for multiple, smaller antennas to handle more frequency bands. The DTCs help overcome efficiency challenges associated with smaller antenna sizes by improving antenna tuning and reconfiguration. Importantly, this solution avoids reliability issues common in current RF MEMS designs by eliminating dielectric materials prone to charging and breakdown.
According to Nanusens, 6G's higher frequency bands can help unlock a myriad of new applications and pave the way for the promised data rates of up to 1,000 gigabits per second. The company's new solution may help to meet the escalating demands of data-intensive applications such as AI, virtual reality, augmented reality, and IoT.
Solid State vs. MEMS for RF
Solid-state switches in RF systems face significant challenges primarily due to their inherent material and structural limitations.
These switches typically rely on semiconductor materials like silicon. While excellent for many electronic applications, silicon struggles to meet certain demands of RF systems. For example, solid-state switches often struggle with high insertion loss, leading to signal degradation and poor isolation, which can cause signal leakage and interference. Additionally, their linearity issues can cause signal distortion, further complicating their integration into advanced RF systems.
Cross section of a MEMS-within-CMOS device. This technology combines MEMS's mechanical properties with CMOS's electronic capabilities on a single chip using the same fabrication process.
Integrating these devices reduces parasitic capacitance, which in turn enhances the performance of MEMS devices by increasing their sensitivity and reducing power consumption. By minimizing the parasitic effects, MEMS-within-CMOS technology also achieves better linearity and reliability than traditional solid-state switches.
Furthermore, MEMS-within-CMOS technology enables combo chips, which integrate multiple sensors or switches on a single die. This reduces the final product's size and cost. It also enhances its performance by eliminating the need for wire bonding and other interconnection methods that can introduce parasitic elements and signal degradation.
A Step Toward 6G Adoption?
As the industry continues to push the boundaries of what's possible in mobile connectivity, innovations like Nanusens' MEMS-within-CMOS technology could be instrumental in supporting 6G. While primarily aimed at smartphone and mobile applications, the new technology could also impact other markets, including industrial and automotive applications.
