Flat Group Delay RF Front End for Precise Time Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radio-frequency signal reception systems face challenges in achieving accurate time synchronization and ranging due to frequency-dependent group delays introduced by transceivers, which limit the accuracy of propagation delay and time bias calculations in multiband two-way ranging protocols.
Innovation Solution
The RF system employs a self-complementary antenna with a resistive matching network and passive coupling device to maintain a flat group delay across the operational frequency band, allowing for precise timestamping and reduced calibration time by reflecting transmitted signals to generate local reference signals, thereby minimizing frequency-dependent variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional transceivers are used for RF signal reception, then signal reception functionality is achieved, but frequency-dependent group delays are introduced that reduce time synchronization and ranging accuracy
Solution Approach 1:
The patent changes the electrical length parameters of transmission lines and resonator configurations to achieve a flat group delay response across the operating bandwidth. By carefully selecting the lengths of transmission lines (e.g., λ/4, λ/2 at specific frequencies) and configuring resonator circuits, the system compensates for frequency-dependent delays inherent in conventional transceivers, achieving sub-100ps group delay variation across 700MHz-2.5GHz bandwidth.
2Productivity
If multiband two-way ranging protocols are implemented with conventional transceivers, then ranging functionality is achieved, but calibration time is extended and accuracy is reduced due to frequency-dependent variability
Solution Approach 1:
The patent implements preliminary group delay equalization through the antenna circuit design before signal processing. By pre-compensating for frequency-dependent delays in the RF front-end through carefully designed transmission line lengths and resonator configurations, the system eliminates the need for extensive per-band calibration procedures, reducing calibration time while maintaining sub-100ps ranging accuracy across all bands.
3Adaptability or versatility
If wide operational bandwidth is covered, then multiband communication capability is achieved, but group delay variability increases across the frequency band
Solution Approach 1:
The patent introduces resonator circuits as intermediary elements between the antenna and transceiver. These resonators are configured to provide frequency-dependent phase compensation that counteracts the group delay variations introduced by the wideband antenna and transceiver chain. The resonators act as mediators that equalize the group delay across the 700MHz-2.5GHz bandwidth, enabling consistent time synchronization performance across all operating bands.
Data Source
AI summary
A radio-frequency system including: a self-complementary antenna characterized by an input impedance substantially independent of signal frequency across an operational frequency band; a passive coupling device characterized by a characteristic impedance and configured to couple the self-complementary antenna to a signal generator and a set of signal processors; a resistive matching network electrically connected between the self-complementary antenna and the passive coupling device configured to match the characteristic impedance of the passive coupling device to the input impedance of the self-complementary antenna; and a back-coupling line characterized by a substantially constant group delay across the operational frequency band configured to electromagnetically couple the signal generator to the set of signal processors.