Doherty Amplifier Segmentation for Mode S Identification Power

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Solution Overview

Problem

Identification antenna systems face challenges in minimizing power losses when operating in mode S, where the sum and delta channel interrogation signals are transmitted simultaneously, leading to a potential fourfold increase in required transmission power, which is difficult for existing amplifiers to manage efficiently.

Innovation Solution

The antenna system employs a Doherty amplifier configuration with a main power amplifier and an auxiliary power amplifier, along with a power splitter and combiner node, to manage the increased transmission power without using switches, allowing for up to a 6 dB increase in transmission power while maintaining efficiency by operating both amplifiers in saturation mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a single amplifier is used to manage peak power, then the amplifier must be oversized for peak operation, but efficiency is lost during normal operation

Engineering Contradiction:
Improvepeak transmission powerVSAvoidamplifier efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The power amplifier is segmented into a main amplifier and an auxiliary amplifier. The main amplifier handles normal power operation, while the auxiliary amplifier is activated only during peak power requirements. This segmentation allows each amplifier to operate at optimal efficiency levels for their respective power ranges, avoiding the inefficiency of using an oversized single amplifier.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different amplifier configurations based on power requirements. During normal operation, only the main amplifier is active. When peak power is needed, the auxiliary amplifier is dynamically activated and combined with the main amplifier through a power combiner, allowing the system to adapt its power output capability in real-time.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If switches are used to activate amplifiers, then amplifier activation can be controlled, but power loss and complexity increase

Engineering Contradiction:
Improveamplifier activation controlVSAvoidpower loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent replaces mechanical switches with a signal-based activation mechanism. The auxiliary amplifier is activated through signal routing and combining rather than mechanical switching, which eliminates contact resistance and mechanical wear while reducing power loss associated with switch operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If mode S transmission is implemented, then identification functionality is improved, but transmission power requirement increases fourfold

Engineering Contradiction:
Improveidentification functionalityVSAvoidtransmission power
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The power amplification function is segmented into main and auxiliary amplifiers that can be independently controlled. This segmentation enables the system to provide the high peak power required for mode S transmission only when needed, rather than continuously operating at high power levels, thus managing the fourfold power increase requirement efficiently.

Inventive Principle:
Principle #1Segmentation

4Adaptability or versatility

If high power phase shifters are used, then beam steering capability is maintained, but weight and complexity increase

Engineering Contradiction:
Improvebeam steering capabilityVSAvoidphase shifter weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

Instead of using a single high-power phase shifter designed for maximum power handling, the system uses two lower-power phase shifters (one for each amplifier) that operate at reduced power levels during normal operation. This partial action approach reduces the weight and complexity of each individual phase shifter while maintaining the required beam steering capability through the combined output of both amplifiers.

Inventive Principle:
Principle #16Partial or excessive action

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 configuration effectively doubles the transmission amplitude and quadruples the transmission power without significant power loss, maintaining high efficiency and reducing the need for complex mechanical rotators or high-power phase shifters, thus enhancing the system's operational efficiency and reducing weight and cost.

Implementation Method 1

a power combiner node, wherein the power combiner node combines (at least) the first and second amplifier signals of the main power amplifier circuit and the auxiliary power amplifier circuit

Methodology Applied
Scientific EffectElectromagnetic signal combination: Interference

Data Source

PatentEP3281032B1An improved antenna system for providing identification functionality
Publication Date: 2019.12.25 SAAB AB
  • EP3281032B1 patent drawingFigure 1
  • EP3281032B1 patent drawingFigure 2
  • EP3281032B1 patent drawingFigure 3

AI summary

The present disclosure relates to an antenna system for providing identification functionality comprising an amplifying circuitry, wherein the amplifying circuitry in turn comprises; a splitter node, wherein the splitter node is configured to split a transmission signal in at least a first and a second amplifier signal, a main power amplifier circuit, wherein the main power amplifier circuit comprises a main amplifier and wherein the main amplifier is configured to amplify the first amplifier signal, an auxiliary power amplifier circuit, wherein the auxiliary power amplifier circuit comprises an auxiliary amplifier and wherein the auxiliary amplifier is configured to amplify the second amplifier signal, and a power combiner node, wherein the power combiner node is configured to combine the first and the second amplifier signal of the main power amplifier circuit and the auxiliary power amplifier circuit. The main power amplifier circuit and the auxiliary power amplifier circuit are provided in parallel between the power splitter node and the power combiner node. The present disclosure also relates to an active electrically steerable antenna comprising such an antenna system, methods to control such antenna systems and a computer program, preferably stored on a computer readable medium, configured to be run on a computer or like for controlling the antenna system.