Integrated Directional Coupler and Low Pass Filter
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Solution Overview
Problem
RF systems require multiple components for impedance transformation and directional coupling, leading to increased cost and size due to separate circuitry for low pass filters and directional couplers.
Innovation Solution
A directional coupler that integrates a low pass filter with detector circuitry, using a filter inductor and capacitor to provide impedance transformation and directional coupling with a common set of components, eliminating the need for separate devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If separate low pass filter and directional coupler components are used, then impedance transformation and directional coupling functions are provided, but the number of components increases leading to increased cost and size
Solution Approach 1:
The patent combines the low pass filter and directional coupler into a single integrated device where the filter inductor and capacitor serve dual purposes: providing impedance transformation and enabling directional coupling through magnetic coupling to detector circuitry. This merging eliminates separate components while maintaining both functions.
Solution Approach 2:
The filter inductor and capacitor are designed to perform multiple functions simultaneously: they provide low pass filtering, impedance transformation, and serve as part of the directional coupler structure through magnetic coupling to the detector. This multi-functionality reduces the overall component count.
2Area of stationary object
If multiple separate components are used for impedance transformation and directional coupling, then adequate functionality is provided, but the size and cost of the RF system increases
Solution Approach 1:
The directional coupler and low pass filter are merged into a single compact structure where the filter inductor is magnetically coupled to the detector inductor, and the filter capacitor is connected to the output port and ground. This integration significantly reduces the space occupied by components.
Solution Approach 2:
The same filter inductor and capacitor that provide low pass filtering and impedance transformation also serve as part of the directional coupling mechanism through their magnetic coupling to the detector circuitry, eliminating the need for separate directional coupler components.
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
This integration reduces the number of components in RF amplification devices, resulting in a more compact and cost-effective RF system design while maintaining high directivity and impedance transformation efficiency.
Implementation Method 1
The filter inductor is magnetically coupled to the detector inductor in the detector circuitry such that current passing through the filter inductor generates a detector current through the detector inductor
Implementation Method 2
the low pass filter and the detector circuitry cooperate to transform a first impedance presented at the output port to a second impedance presented at the input port
Data Source
AI summary
A directional coupler that provides directional coupling and an impedance transformation is disclosed. In one embodiment, the directional coupler includes a low pass filter having a filter inductor that is coupled between an input port and an output port and a filter capacitor coupled between the output port and ground. The directional coupler also includes detector circuitry wherein the filter inductor is magnetically coupled to a detector inductor in the detector circuitry such that current passing through the filter inductor generates a detector current through the detector inductor. Furthermore, the low pass filter and the detector circuitry cooperate to transform a first impedance presented at the output port to a second impedance presented at the input port. Accordingly, the filter inductor is used in the low pass filter to provide an impedance transformation so as to operate with the detector circuitry to provide a detector current for directional coupling.