Compact and wideband nanoacoustic pass-band filters for future 5G and 6G cellular radios

Abstract

The last half a century has seen an enormous growth in mobile communication, reflecting into an increasingly interconnected world. Nevertheless, the incessant demand for faster data-rates requires a shift to higher carrier frequencies, which translates to the need for more ubiquitous hardware due to the increased wave propagation losses. The 7-20 GHz range, located between the sub-6 GHz (5G FR-1) and the mm-wave (5G FR-2) spectrum, provides an excellent trade-off between network capacity and coverage. Such spectrum portion constitutes a yet-to-explore third frequency range (FR-3) for future 5G applications, and is foreseen to become the 6G mid-band, devoted to crowded urban area coverage. This work proposes a technological platform able to deliver CMOS-compatible, on-chip multi-frequency low-loss, wideband, and compact passband filters for cellular radios operating at mid-band frequencies, exploiting the micro-to-nano scaling of acoustic electromechanical resonators and filters. The presented results showcase the first-ever demonstrated low insertion loss bank of 7 nanoacoustic passive passband filters in the X-band, spanning more than 3 GHz of operation, all fabricated on the same substrate with state-of-the-art and low-complexity micro-machining process. Most of the filters showcase fractional bandwidths above 3% and sub-dB loss per stage, all in an extremely compact form factor, enabling the manufacturing of X-band filters and duplexers that can be integrated in mobile handsets at each antenna element. The novelty of the current results stems from the adoption of a high-crystallinity piezoelectric Sc-doped AlN thin film, together with an optimized resonator topology in terms of design and fabrication.

Filter cable design with defected conductor transmission structures

“…According to the basic framework of any electromagnetic compatibility (EMC) design 3 , electrical cables not only conduct electromagnetic interference (EMI), leading to symptoms of conducted emissions (CE) and conducted susceptibility (CS) 4,5 , but also radiate electromagnetic energy 6 , causing issues with radiated emissions (RE) and radiated susceptibility (RS) 7,8 . Moreover, with the rapid advancements in technology, including the smart grid, next-generation communication technologies 9 , the Internet of Things (IoT) 10 , unmanned systems, and artificial intelligence, the development and application of critical infrastructure and advanced intelligent equipment and systems have become pivotal factors in achieving reliable and secure operations. In this regard, ensuring reliability in a complex electromagnetic environment is a critical consideration for the effective functioning of various intelligent equipment systems 11 .…”

Recent progress on structural coloration

“…We want to emphasize that the research on structural colors is essentially developing powerful processors for spectral information with extremely high spatial resolution and spectral accuracy. Although developed originally for visible light, the spectral processing capabilities of structural coloration are transferrable to all parts of the spectrum, including the terahertz waves that are expected to be the range for 6G wireless communications [318,319] . The ability to modulate the spectral information with high spatial resolution can become a game-changing technique for enabling high-throughput information processing for both free-space and fiber-optics systems.…”

Experimental realisation of a universal inverse-design magnonic device

“…The fields of electronics and telecommunications ongoing research greatly revolves around frameworks like the Internet of Things (IoT), 5G and 6G technologies [1]. These frameworks require RF devices that support high-speed and high-capacity wireless communication, which are vastly used in our mobile phones, autonomous vehicles, smart cities, and advanced healthcare monitoring systems [2]. Therefore there is a continuous need to design, test, and optimise new advanced quickly-reconfigurable RF components that operate in a wide range of frequencies and bandwidths with low energy consumption.…”