Directional Couplers with Integrated DC Insulated Ports
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Solution Overview
Problem
Conventional directional couplers for mobile 5G applications require separate components for DC blocking, leading to size and cost inefficiencies due to the need for discrete components and minimum gap requirements during mounting.
Innovation Solution
A directional coupler design incorporating three coupled sections and a delay section with integrated DC insulation, allowing for DC isolation between input and output ports, thereby combining the functions of a conventional coupler and a DC blocking capacitor into a single component, reducing size and cost while maintaining RF performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC blocking capacitor is placed at the output of the directional coupler, then DC isolation is achieved, but the device size and complexity increase due to additional discrete components
Solution Approach 1:
The patent combines the DC blocking capacitor function with the directional coupler structure by integrating a capacitive element into the transmission line configuration. The capacitive coupling between conductors provides both the directional coupling function and the DC blocking function simultaneously, eliminating the need for a separate discrete DC blocking capacitor.
Solution Approach 2:
The transmission line structure is designed to perform multiple functions: it provides directional coupling for RF signal sampling while simultaneously blocking DC current through its capacitive coupling mechanism. This multi-functional design allows a single component to replace what would traditionally require multiple discrete components.
2Reliability
If separate DC blocking components are used, then DC isolation is ensured, but manufacturing cost and assembly complexity increase due to minimum gap requirements
Solution Approach 1:
The DC blocking function is merged into the coupler's transmission line structure through capacitive coupling between conductors. This integration eliminates the need for separate DC blocking components and their associated assembly requirements, allowing the entire assembly to be manufactured as a single integrated unit with fewer manufacturing constraints.
3Reliability
If conventional directional coupler design is used with separate DC blocking, then DC isolation is achieved, but the overall size increases due to additional components
Solution Approach 1:
The patent merges the DC blocking capacitor function into the directional coupler's transmission line structure by using capacitive coupling between conductors. This integration eliminates the need for separate discrete components, thereby reducing the overall device footprint while maintaining the required DC isolation functionality.
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
The integrated DC blocking directional coupler achieves size reduction, cost savings, and maintains RF performance similar to conventional couplers, with improved directivity and return loss, making it suitable for compact mobile 5G applications.
Implementation Method 1
a first coupled section comprising a first and a second coupled transmission lines, the first coupled transmission line having a first end coupled to an input port
Implementation Method 2
A DC blocking capacitor is often placed at the output of the directional coupler and prevents the DC bias of the power amplifier from flowing down to the next stage
Data Source
AI summary
A directional coupler may include a first coupled section comprising a first and a second coupled transmission lines, the first coupled transmission line having a first end coupled to an input port. The directional coupler may also include a second coupled section comprising a first and a second coupled transmission lines. The directional coupler may also include a third coupled section comprising a first and a second coupled transmission lines. The first coupled transmission line of the third coupled section has a first end coupled to a second end of the second coupled transmission line of the second coupled section and a second end coupled to an output port. The directional coupler may further include a delay section. A total electrical length of the first coupled section, the second coupled section, the third coupled section, and the delay section is about 90 degrees.