THz Beam Scanning Using True Time Delay for Real-Time Sensing
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Solution Overview
Problem
High path loss and narrow beams at THz frequencies in radar systems lead to slow scanning and missed detection of rapidly-changing activities, while fully digital beamforming is costly, and analog beamforming is limited in advanced cellular systems.
Innovation Solution
Implementing a hybrid beamforming technique using true time delay (TTD) elements and phase shifters for coarse and fine-grained sensing, combined with time division multiplexing (TDM) and multiple thread processing to enhance scanning speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If analog beamforming is used at THz frequencies, then device complexity is reduced, but scanning speed decreases and detection accuracy is limited
Solution Approach 1:
The patent combines analog beamforming (using phase shifters) with digital beamforming (using TTD elements and baseband processing) to create a hybrid beamforming architecture. This merging allows the system to achieve both low complexity and high scanning speed by distributing beamforming functions across analog and digital domains, enabling parallel beam processing while maintaining hardware efficiency.
Solution Approach 2:
The beamforming function is segmented into multiple independent components: analog phase shifters for spatial beam shaping, digital TTD elements for time delay control, and baseband processing for signal refinement. This segmentation allows each component to operate independently at optimal speeds, with digital segments processing multiple beams simultaneously to accelerate scanning without increasing overall system complexity.
2Speed
If fully digital beamforming is implemented, then scanning speed and detection accuracy improve, but system cost increases significantly
Solution Approach 1:
Instead of implementing full digital beamforming across all antenna elements, the patent applies digital processing selectively to a subset of receive chains while using analog beamforming for the majority of spatial beam control. This partial digitalization achieves sufficient scanning speed and detection accuracy for the application while dramatically reducing the number of expensive digital-to-analog converters and processing channels required.
Solution Approach 2:
The patent introduces TTD (true time delay) elements as an intermediary component between the analog RF front-end and the digital baseband processing. These TTD elements provide precise time delay control in the analog domain, enabling accurate beamforming without requiring full digitalization of the signal path, thus reducing system cost while maintaining scanning performance.
3Measurement precision
If narrow beams are used at THz frequencies, then angular resolution improves, but scanning coverage decreases and detection of rapidly-changing activities is missed
Solution Approach 1:
The patent implements continuous scanning by rapidly switching between multiple narrow beams in a systematic sequence, ensuring that the entire field-of-view is covered without gaps. The beam switching is synchronized with signal processing to maintain continuous target detection, allowing the system to achieve both high angular resolution from narrow beams and comprehensive scanning coverage through uninterrupted beam traversal.
Solution Approach 2:
The patent employs periodic beam sweeping patterns where narrow beams systematically traverse the field-of-view in repeated cycles. This periodic action ensures that rapidly-changing activities are captured within the scanning period, while the narrow beam width maintains high angular resolution. The periodic nature allows for predictable timing and synchronization with data processing operations.
Data Source
AI summary
A method for real-time THz sensing using true time delay (TTD) is implemented by a base station and includes transmitting, by a transceiver that includes TDD elements and phase shifters configured in the transceiver, simultaneous frequency dependent (SFD) beams to scan an environment at a first granularity to detect a spatial cluster target. Each of the SFD beams corresponds to a different phase angle and different frequency. The method includes determining, among the SFD beams, a subset of beams that detected the spatial cluster target. The method includes beam switching, by the transceiver, using time division multiplexing (TDM) and a TDM bandwidth to scan a portion of the environment at phase angles corresponding to the subset of beams and at a second granularity finer than the first granularity. The method includes combining data received from the SFD beams, by multiple threads that concurrently process data received from the SFD beams.