Bidirectional Coupler Segmented Line Attenuators
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Solution Overview
Problem
Conventional bi-directional couplers face challenges in achieving perfect matching between ports, leading to parasitic reflections and measurement errors due to mismatched impedance, which existing solutions like attenuators only postpone and increase transmission losses.
Innovation Solution
A distributed-line directional coupler design with a second conductive line interrupted in the middle, connected to attenuators, and a directional coupling circuit with resistive power separators, allowing for independent adjustment of attenuators to match the directivity factor, reducing coupler bulk and sensitivity to port matching variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If attenuators are added to the ends of the secondary line to overcome mismatch, then measurement reliability is improved, but coupling must be increased which increases coupler size and transmission losses
Solution Approach 1:
The second conductive line is divided into three segments: a first section from the third port to a first intermediate point, a second section from the first intermediate point to a second intermediate point, and a third section from the second intermediate point to the fourth port. The attenuators are placed only at these intermediate points rather than at both ends, segmenting the attenuation function to reduce overall coupling requirements while maintaining measurement reliability.
Solution Approach 2:
Attenuators are selectively placed only at specific intermediate points along the second conductive line rather than uniformly at both ends. This local placement optimizes the attenuation effect precisely where needed to handle mismatch issues, reducing the overall coupling factor requirement and associated transmission losses while maintaining measurement reliability.
2Reliability
If coupling is increased to compensate for mismatch, then measurement reliability is improved, but coupler size increases
Solution Approach 1:
The second conductive line is divided into three segments with attenuators placed only at intermediate points. This segmentation allows the coupler to maintain adequate coupling factor without excessive increase in physical size, as the attenuators are strategically positioned to provide necessary attenuation without requiring uniform high coupling across the entire line.
Solution Approach 2:
Attenuators are placed locally at intermediate points rather than requiring increased coupling across the entire second conductive line. This localized approach provides the necessary attenuation to maintain measurement reliability without proportionally increasing the overall coupler dimensions.
3Object-generated harmful factors
If perfect matching is required at all ports, then parasitic reflections are eliminated, but manufacturing precision requirements increase
Solution Approach 1:
Attenuators are introduced as intermediary elements at intermediate points on the second conductive line. These attenuators act as mediators that absorb and dampen potential parasitic reflections caused by impedance mismatches, eliminating the need for perfect matching at all ports while still reducing harmful reflections.
Solution Approach 2:
The invention converts the potentially harmful effect of impedance mismatch into a beneficial feature by using the mismatch-induced reflections as an opportunity to place attenuators at strategic intermediate points. These attenuators then utilize the reflected energy to provide additional attenuation, turning what would be a harmful reflection into a useful attenuation mechanism that reduces parasitic reflections overall.
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 design significantly reduces parasitic reflections and measurement errors by decoupling the coupler's operation from port matching issues, maintaining high directivity and reducing transmission losses, while allowing for independent adjustment of attenuators to optimize performance.
Implementation Method 1
the two intermediary ends being connected to attenuators
Implementation Method 2
a directional coupling circuit with resistive power separators
Data Source
AI summary
A distributed-line directional coupler including: a first conductive line between first and second ports intended to convey a signal to be transmitted; and a second conductive line, coupled to the first one, between third and fourth ports, the second line being interrupted approximately at its middle, the two intermediary ends being connected to attenuators.