Optical Modulator FPC Attenuation for RF Signal Reflection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical modulators with flexible printed circuits (FPCs) face impedance mismatching issues due to manufacturing variations, leading to radio frequency signal reflection and unstable operation in optical transmission systems.
Innovation Solution
Incorporating radio frequency attenuation portions in the FPCs, formed with materials like carbon and/or ferrite, which attenuate the signal power by bending the propagation direction of the radio frequency signal by at least 90 degrees, thereby reducing signal reflection and stabilizing the operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If lead pins and FPC are used instead of coaxial connectors to reduce package size, then the package case size is reduced, but impedance mismatching occurs due to manufacturing variations causing signal reflection
Solution Approach 1:
The patent introduces radio frequency attenuation portions that deliberately attenuate the radio frequency signal to convert the harmful effect of impedance mismatching and signal reflection into a beneficial outcome. By placing attenuation portions at specific locations in the FPC wire patterns, the reflected signals are attenuated before returning to the circuit substrate, thereby stabilizing the optical modulator operation while maintaining the compact package design.
Solution Approach 2:
The radio frequency attenuation portions act as intermediary elements between the signal source and the impedance mismatch point. These attenuation portions, formed by loading carbon and/or ferrite materials onto the FPC wire patterns, serve as a mediator that reduces the impact of impedance variations caused by manufacturing tolerances, thereby improving signal transmission stability without requiring larger package dimensions.
2Reliability
If radio frequency attenuation portions are added to FPC wire patterns, then signal reflection is reduced and operation is stabilized, but device complexity increases
Solution Approach 1:
The patent applies radio frequency attenuation portions only at specific local positions within the FPC wire patterns rather than uniformly across the entire FPC. The attenuation portions are strategically placed at locations where impedance mismatching is most likely to occur, such as near connection points or at transitions between different trace geometries. This localized approach provides the necessary signal stabilization while minimizing the overall complexity and material usage.
Solution Approach 2:
The patent employs composite material structures by loading carbon and/or ferrite materials onto the FPC wire patterns to create radio frequency attenuation portions. These composite structures combine the conductive properties of the FPC trace with the electromagnetic loss characteristics of carbon and/or ferrite, achieving effective signal attenuation and reflection reduction. The composite material approach allows for controlled impedance management without requiring complete redesign of the FPC architecture.
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 attenuation of radio frequency signals in the FPCs effectively reduces signal reflection, maintaining high light transmission quality and preventing unstable phenomena in optical modulators.
Implementation Method 1
the wire pattern includes at least one radio frequency attenuation portion for attenuating power of the radio frequency signal by a predetermined amount
Data Source
AI summary
In an optical modulator including an FPC for performing electrical connection with an external circuit substrate, to maintain high light transmission quality by appropriately driving the optical modulator even when the reflection of a radio frequency signal occurs in a connection portion between the FPC and the main body of the optical modulator. Provided is an optical modulator including a flexible printed circuit for performing electrical connection with a circuit substrate, in which the flexible printed circuit includes at least one wire pattern for propagating a radio frequency signal, and the wire pattern includes at least one radio frequency attenuation portion for attenuating power of the radio frequency signal by a predetermined amount.