RF Power Divider With Quarter Wave Transformers

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Solution Overview

Problem

Existing RF power divider arrangements, such as those using Wilkinson power dividers, often face limitations in achieving power split ratios exceeding 3 dB, especially in corporate fed RF antenna arrays requiring higher amplitude distributions, and may experience degraded performance.

Innovation Solution

A novel RF power divider circuit utilizing a combination of quarter wave transformers and resistors, with resistive elements and a dielectric substrate, allows for unequal power splitting across output ports, enabling power split ratios up to 9 dB with loosely controlled resistor values and wide frequency band operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If Wilkinson power dividers are used to split power among array elements, then power distribution is achieved, but power split ratios are limited to approximately 3 dB and performance degrades at higher ratios

Engineering Contradiction:
Improvepower split ratioVSAvoidperformance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The power divider is segmented into multiple functional sections: a first Wilkinson power divider section for initial power splitting, a transmission line section for impedance transformation and phase adjustment, and a second Wilkinson power divider section for final power distribution. This segmentation allows each section to be optimized for its specific function, enabling high power split ratios while maintaining performance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite transmission line structures combining different characteristic impedances (e.g., 50-ohm, 70-ohm, 90-ohm lines) and different physical configurations (microstrip, stripline, coplanar waveguide) to achieve the required impedance transformations and power distribution ratios while maintaining broadband operation

Inventive Principle:
Principle #40Composite materials

2Power

If standard Wilkinson power dividers are used, then simple structure is achieved, but power split ratios cannot exceed 3 dB effectively

Engineering Contradiction:
Improvepower split ratioVSAvoidcircuit structure
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The invention merges multiple Wilkinson power divider sections with transmission line sections into a single integrated power divider circuit. The first Wilkinson section, transmission line section, and second Wilkinson section are combined to create a unified structure that achieves high power split ratios (e.g., 9 dB or greater) while maintaining the simplicity and robustness of Wilkinson divider topology throughout

Inventive Principle:
Principle #5Merging (Combining)

3Power

If high power split ratios are required for tapered amplitude distribution, then antenna performance is improved, but conventional power dividers cannot achieve these ratios

Engineering Contradiction:
Improveamplitude distributionVSAvoidpower distribution capability
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The invention changes key parameters including transmission line characteristic impedances, line lengths, and the configuration of resistive elements to enable high power split ratios. By adjusting these parameters, the power divider can be tailored to provide specific amplitude distributions (e.g., tapered distributions for low side-lobe antenna arrays) while maintaining adaptability for different power split requirements

Inventive Principle:
Principle #35Parameter changes

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 provides a precision matched, in-phase power divider capable of achieving high power split ratios with relaxed resistor tolerance, suitable for wide-band and low side-lobe antenna arrays, enhancing performance and reducing manufacturing complexity.

Implementation Method 1

The circuit includes a single input port, first and second output ports, and a specific combination of a plurality of quarter wave transformers and a plurality of resistors coupled between the input port and the first and second output ports

Methodology Applied
Scientific EffectQuarter wave transformer:

Implementation Method 2

the plurality of quarter wave transformers include a dielectric substrate and a conductor strip pattern formed on the dielectric substrate

Methodology Applied
Scientific EffectResistive dissipation: Joule Heating

Data Source

PatentEP1920494B1Power divider
Publication Date: 2010.10.06 RAYTHEON CO
  • EP1920494B1 patent drawingFigure 1
  • EP1920494B1 patent drawingFigure 2
  • EP1920494B1 patent drawingFigure 3A~3E

AI summary

An RF power divider circuit (1 ) unequally divides an input signal into first and second signal components of unequal power. The circuit includes a single input port (21 ), first and second output ports (22, 23), and a combination of a plurality of quarter wave transformers (10-17) and a plurality of resistors (31 , 31 ) coupled between the input port and the first and second output ports.