Interconnected Microstrip Directional Couplers for Cable Network Amplifiers

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Solution Overview

Problem

Existing cable network amplifiers fail to compensate for increased signal losses at higher frequencies, leading to distorted signals and data loss, and are inflexible and costly due to complex architectures with ferrite directional couplers and signal splitters.

Innovation Solution

A multiport amplifier using a series of interconnected microstrip directional couplers with separate upstream and downstream paths, connected by transformers, allowing for variable gain and tilt to accommodate different coaxial cable lengths and frequencies up to 2000 MHz, with phase-inverting transformers for upstream signals and resistive termination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If ferrite directional couplers and signal splitters are used in the amplifier architecture, then the amplifier can handle multiple signals, but the device complexity and production cost increase significantly

Engineering Contradiction:

Improvemulti-signal handling capabilityVSAvoidamplifier architecture complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The amplifier is divided into multiple independent port sections, each with its own microstrip directional coupler and amplifier circuit. This segmentation allows each port to be designed and manufactured independently, reducing overall complexity while maintaining multi-signal handling capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The microstrip directional coupler structure serves multiple functions simultaneously: it provides signal splitting, isolation between ports, and impedance matching. This multi-functionality eliminates the need for separate ferrite couplers and signal splitters, reducing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If traditional amplifier architecture with ferrite directional couplers is used, then signal splitting is achieved, but production cost increases

Engineering Contradiction:

Improvesignal splitting capabilityVSAvoidproduction cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive ferrite directional couplers with microstrip directional couplers that can be manufactured using standard PCB techniques. These microstrip structures are much cheaper to produce and can be manufactured in large quantities with consistent performance

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces mechanical/ferrite-based directional couplers with planar microstrip transmission line structures that are etched onto circuit boards. This substitution enables standard manufacturing processes to be used, dramatically reducing production costs

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If higher frequencies are used to increase bandwidth, then more data transmission is achieved, but signal loss in coaxial cable increases

Engineering Contradiction:

Improvedata transmission capacityVSAvoidsignal loss in coaxial cable

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent uses variable gain control for each output port to compensate for frequency-dependent cable losses. By adjusting the gain parameters of individual amplifier channels, the system maintains consistent signal levels across the extended frequency range and different cable lengths

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent incorporates tilt control mechanisms that provide feedback compensation for frequency-dependent losses. The tilt control adjusts the frequency response of each port to compensate for the increased signal loss at higher frequencies in the coaxial cable

Inventive Principle:

Principle #23Feedback

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 effectively compensates for signal losses across different cable lengths, maintains signal quality at high frequencies, reduces production costs, and allows for easy frequency range adjustments without reconfiguring other components, ensuring high isolation and flexibility.

Implementation Method 1

The isolated port of alternate microstrip directional couplers in the series is connected to the isolated port of one adjacent microstrip directional coupler using at least one transformer

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

a phase inverting transformer is disposed between the input and each microstrip directional coupler output port, such that all upstream signals pass through the phase-inverting transformer before reaching the input

Methodology Applied

Scientific EffectPhase inversion:

Data Source

PatentUS10194193B2Cable network device having interconnected microstrip directional couplers

Publication Date: 2019.01.29 TECHNETIX

AI summary

There is provided a cable network device comprising an input associated with a plurality of outputs, wherein each output is connected to a respective microstrip directional coupler and each microstrip directional coupler is connected to at least one of the other microstrip directional couplers. The microstrip directional couplers form a series of microstrip directional couplers, with a last microstrip directional coupler in the series having its output port terminated by a resistive element. An isolated port of each microstrip directional coupler is in electrical communication with the upstream path.