Ultra-compact quasi-true time delay for boosting wireless channel capacity

• 成果类型: Article
• 署名作者: Govind, Bala; Tapen, Thomas; Apsel, Alyssa
• 署名单位: Cornell University
• 刊物名称: Nature
• ISSN/ISSBN: 0028-3741
• DOI: 10.1038/s41586-024-07075-y
• 发表日期: 2024-03-07
• 关键词: infrared spectrograph nirspec; supermassive black-holes; star-formation; luminosity function; interstellar-medium; emission; galaxies; jwst; ultraviolet; performance

摘要

Massive-data connectivity has driven the need for efficient, directed communications through beamforming arrays1-10. Delay elements are critical in any beamforming signal chain. However, these elements impose fundamental limits on size, channel capacity, power efficiency and effective isotropic radiated power11. Although passive phase shifters do not consume DC power, they suffer from narrow bandwidth, poor phase resolution and low power-handling capacity. They introduce a beam squint, in which different frequency components experience different time delays, blurring signals so that they cannot be resolved. This severely limits the data rate of the wireless link, that is, its channel capacity. Although true time delay (TTD) elements12 solve this problem and service a broad bandwidth, they comprise wavelength-scale transmission lines, making them prohibitively area-inefficient for modern semiconductor processes. Here we address this long-standing problem by introducing a quasi-true time delay (Q-TTD) that miniaturizes TTD elements and breaks fundamental channel-capacity limits of these wireless links. We demonstrate this mechanism for a microwave device implemented in a complementary metal-oxide-semiconductor (CMOS) technology. Key to shrinking the footprint is a reflective-type phase-shifting structure with 3D variable TTD reflectors within a sub-wavelength footprint. This achieves ultra-broadband phase tuning by using them to vary the length of the waveguide's path to ground. They produce a delay-to-area ratio that yields a substantially higher on-chip channel capacity compared with existing state-of-the-art methods. This component, when integrated in arrays, enables high-resolution imaging and low-squint beamforming for wideband communication, on-chip radar and other applications. A quasi-true time delay is demonstrated for a microwave device implemented in a CMOS technology to miniaturize true-time-delay components of beam-steering systems, addressing the fundamental channel-capacity limitations and increasing data transmission in wireless communications.