Cable Tap Using Microstrip and Ferrite Couplers for Low Insertion Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cascaded cable networks experience signal attenuation issues due to the varying power requirements of taps placed in series, leading to inefficiencies in signal transmission, particularly in outdoor installations where traditional taps result in high insertion loss.
Innovation Solution
A cable tap device combining a microstrip directional coupler and a ferrite directional coupler interconnected in series, with capacitive and inductive elements, to create a bi-directional tap unit with low insertion loss and tilted tap loss characteristic, allowing efficient signal transmission across a wide frequency range without the need for filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional ferrite cable taps are used in cascaded networks, then signal transmission is achieved, but insertion loss becomes high
Solution Approach 1:
The directional coupler is divided into two distinct sections: a microstrip coupler section and a ferrite coupler section. Each section performs a specific function - the microstrip section handles low-frequency signals with lower loss, while the ferrite section handles high-frequency signals. This segmentation allows optimization of each section for its specific frequency range, reducing overall insertion loss compared to a traditional single ferrite coupler design.
Solution Approach 2:
The patent changes the physical and electrical parameters along the length of the directional coupler. The microstrip section has different characteristic impedance and physical dimensions compared to the ferrite section. By varying these parameters along the coupler length and transitioning between different coupling mechanisms (microstrip to ferrite), the design achieves lower insertion loss across the broadband frequency range while maintaining proper signal coupling.
2Adaptability or versatility
If taps are placed in series in cascaded networks, then signal distribution to multiple users is achieved, but signal attenuation increases
Solution Approach 1:
By segmenting the directional coupler into microstrip and ferrite sections, each optimized for different frequency ranges, the patent reduces the attenuation introduced by each tap in the cascaded network. This allows more taps to be placed in series while maintaining adequate signal levels at each user location.
Solution Approach 2:
The changing parameters along the coupler length allow for optimized signal coupling at different stages of the cascaded network. The transition from microstrip to ferrite coupling provides a gradual impedance transformation that reduces reflections and minimizes signal loss, enabling better performance in multi-tap configurations.
3Reliability
If a single ferrite directional coupler is used, then high frequency signal handling is achieved, but low frequency signal loss increases
Solution Approach 1:
The directional coupler is segmented into a microstrip section that handles low-frequency signals and a ferrite section that handles high-frequency signals. The microstrip section has lower loss characteristics at low frequencies, while the ferrite section maintains proper coupling at high frequencies. This frequency-dependent segmentation resolves the contradiction by assigning each frequency range to the most suitable coupling mechanism.
Solution Approach 2:
Different sections of the directional coupler have different local qualities - the microstrip section has properties optimized for low-frequency operation, while the ferrite section has properties optimized for high-frequency operation. This local differentiation allows each section to perform its specific function with minimal loss, achieving overall broadband performance.
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 solution achieves low insertion loss and high tap port isolation, ensuring efficient signal transmission and compensation of high frequency losses across the cable system, maintaining good directivity and preventing low and high frequency signal interference.
Implementation Method 1
The microstrip directional coupler and the ferrite directional coupler are connected together to form a tap unit such that the first output port is connected to the second input port, the isolation port is connected to the second coupling port and the first coupling port connects to one or more tap ports
Implementation Method 2
Capacitive elements may be associated with both types of directional coupler to prevent passage of low frequency signals through the directional couplers
Implementation Method 3
The cable tap device may further comprise inductive elements to prevent passage of high frequency signals through the directional couplers, such as an inductive power choke
Data Source
AI summary
There is provided a cable tap device comprising a microstrip directional coupler having a first input port, a first output port, an isolation port and a first coupling port and a ferrite directional coupler having a second input port, a second output port and a second coupling port, wherein the microstrip directional coupler and the ferrite directional coupler are connected together to form a tap unit such that the first output port is connected to the second input port, the isolation port is connected to the second coupling port and the first coupling port connects to one or more tap ports. Capacitive elements can be associated with both types of directional coupler to prevent passage of low frequency signals through the directional couplers. Inductive elements to prevent passage of high frequency signals through the directional couplers.