Frequency-Selective RF Directional Coupler for Low-Loss Duplex Bands
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Solution Overview
Problem
Practical RF directional couplers face challenges in achieving optimal coupling and minimal main line loss across the operational frequency band, particularly in Full Duplex DOCSIS systems, leading to increased power consumption and reduced signal-to-noise ratio.
Innovation Solution
A frequency selective RF directional coupler design that varies coupling at different frequency bands, using RF filters to enhance coupling where needed and minimize loss where possible, with compensation mechanisms in the communication device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform coupling is applied across the entire operational frequency band, then coupling consistency is improved, but main line loss increases in frequency bands where high coupling is not required
Solution Approach 1:
The patent applies different coupling values at different frequency bands within the operational band. Specifically, it uses a first coupling value for a first frequency band and a second coupling value for a second frequency band, where the coupling values differ. This allows optimization of coupling for each band's specific requirements, reducing main line loss in bands where high coupling is unnecessary while maintaining reliable coupling in bands where it is needed.
Solution Approach 2:
The patent changes the coupling parameter across different frequency bands. By varying the coupling value based on frequency, the system achieves optimal performance for each band without the uniform coupling penalty. This parameter change enables the coupler to adapt to different signal requirements at different frequencies, resolving the contradiction between consistency and loss.
2Power
If high coupling is applied across the entire operational frequency band, then signal power directed to coupled port is improved, but power consumption increases
Solution Approach 1:
The patent applies high coupling only in frequency bands where it is necessary for adequate signal power at the coupled port, while using lower coupling in bands where high coupling is not required. This localized application of high coupling reduces overall power consumption while maintaining necessary signal power levels where needed.
Solution Approach 2:
Instead of applying high coupling uniformly across all frequency bands (excessive action), the patent applies high coupling only partially in specific bands where it is necessary. This partial action achieves the required signal power at the coupled port without the excessive power consumption that would result from uniform high coupling.
3Power
If high coupling is applied across the entire operational frequency band, then signal power directed to coupled port is improved, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent optimizes coupling for each frequency band's specific requirements, applying high coupling only where necessary for adequate signal power while maintaining lower coupling in bands where high coupling would degrade signal-to-noise ratio. This localized optimization preserves signal-to-noise ratio while achieving necessary signal power levels.
4Loss of energy
If low coupling is applied across the entire operational frequency band, then main line loss is reduced, but coupling consistency deteriorates
Solution Approach 1:
The patent applies low coupling in frequency bands where it is sufficient for the application, reducing main line loss in those bands. Simultaneously, it applies higher coupling in bands where adequate signal power is critical, maintaining coupling consistency where needed. This spatially varying coupling approach resolves the contradiction between loss reduction and consistency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces power consumption and improves signal-to-noise ratio by optimizing coupling and loss in specific frequency bands, addressing the conflicting requirements of Full Duplex DOCSIS systems.
Implementation Method 1
a defined portion of the RF signal power which is diverted to the coupled port
Implementation Method 2
a signal applied to the output port will be transferred by the theoretical RF directional coupler to the input port, but not to the coupled port
Data Source
AI summary
A directional coupler having coupling variability at separate portions of an operational frequency band. The coupler may be comprised within a Full Duplex (FDX) amplifier and itself may comprise input and output ports, a coupled port, a termination port, a first RF filter coupled to the coupled port, and a second RF filter coupled to the termination port. The first and second RF filters yield a first coupling value at one portion of the operational frequency band of the coupler and a second coupling value at a second portion of the operational frequency band. The first portion of the band corresponds to a range of frequencies at which higher coupling for the coupler is desired and greater loss in the signal is tolerable. The second portion of the band corresponds to a range of frequencies at which lower coupling for the coupler is tolerable and lower signal loss is desirable.