Electronically Steerable Antenna Phase Offsets for ISLS Control

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Solution Overview

Problem

Electronically steerable antenna systems face challenges in efficiently transmitting ISLS control signals without degrading effective radiated power or requiring additional components, particularly in modes like mode S where simultaneous transmission in sum and delta channels is problematic.

Innovation Solution

A method for controlling an electronically steerable antenna system by applying first and second transmission phase offsets to antenna columns, using existing phase shifters and phase control distribution networks to generate ISLS control signals that meet prevailing standards without additional antennas or tapering, ensuring efficient transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If ISLS control signals are transmitted using conventional methods with separate omnidirectional antennas or tapering, then the control signal transmission is achieved, but the effective radiated power is degraded or additional components are required

Engineering Contradiction:
Improveeffective radiated powerVSAvoidadditional components
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent combines the ISLS control signal transmission function with the existing electronically steerable antenna system that transmits interrogation signals. By using the same antenna elements and phase control mechanisms, the system merges multiple functions into a single integrated structure, eliminating the need for separate omnidirectional antennas while maintaining effective radiated power through coordinated phase offset application to antenna column pairs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electronically steerable antenna system is designed to perform multiple functions: transmitting both interrogation signals and ISLS control signals through the same antenna elements. The phase control distribution network provides multi-functionality by applying different phase offset patterns to the same physical antenna structure, allowing it to serve both surveillance and control signal transmission purposes without requiring additional dedicated components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If tapering is applied to transmit ISLS control signals, then the control signal pattern is achieved, but transmission efficiency and range are significantly lost

Engineering Contradiction:
Improvecontrol signal pattern complianceVSAvoidtransmission efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the phase parameter of the electromagnetic signals transmitted by antenna column pairs rather than reducing amplitude through tapering. By applying first and second phase offsets to create constructive and destructive interference patterns, the system achieves the required ISLS control signal pattern compliance while maintaining full transmission power and efficiency, avoiding the energy losses inherent in amplitude-based tapering methods.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If simultaneous transmission in sum and delta channels is implemented in mode S, then the identification functionality is achieved, but the transmission control becomes problematic

Engineering Contradiction:
Improvemode S identification functionalityVSAvoidtransmission control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic phase control where the phase offsets applied to antenna column pairs can be dynamically adjusted based on the transmission mode. For mode S simultaneous sum and delta channel operation, the system dynamically switches between different phase offset configurations to achieve the required transmission patterns, providing adaptability while managing control complexity through programmable phase control mechanisms.

Inventive Principle:
Principle #15Dynamics

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

Enables the generation of ISLS control signals with desired antenna patterns that comply with standards, maintaining transmission efficiency and range without the need for extra components or tapering.

Implementation Method 1

The RF signals, thus the electromagnetic waveforms, can generally be controlled in phase, amplitude, frequency and/or time. The electromagnetic waves transmitted by the individual antenna elements of an antenna array interfere constructively at certain angles in front of the antenna and form the antenna radiation pattern.

Methodology Applied
Scientific EffectPhase interference: Interference

Implementation Method 2

applying a first transmission phase offset to the electromagnetic waveform distributed to the antenna elements of each antenna column pair, wherein the first transmission phase offset determines the phase offset between the antenna elements of each antenna column pair

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Data Source

PatentEP3446363B1Method for controlling transmission of an electronically steerable antenna system and such electronically steerable antenna system
Publication Date: 2025.07.09 SAAB AB
  • EP3446363B1 patent drawingFigure 1
  • EP3446363B1 patent drawingFigure 2a~2b
  • EP3446363B1 patent drawingFigure 2c

AI summary

The present invention refers to a method for controlling transmission of an electronically steerable antenna system, wherein the electronically steerable antenna system comprises a signal generator configured to generate electromagnetic waveforms, and an antenna. The antenna comprises an even number of antenna columns symmetrically arranged about a centerline of the antenna and thereby forming two symmetrical antenna halves. Respective antenna column comprises at least one antenna element configured at least for transmitting electromagnetic waves. The electronically steerable antenna system is configured for transmitting at least interrogation signals and ISLS control signals, and the method comprises the method steps of, when transmitting the ISLS control signals: generating an electromagnetic waveform; applying a first transmission phase offset to the electromagnetic waveform, wherein the first transmission phase offset determines the phase offset between each antenna column pair; applying a second transmission phase offset to each antenna column of the second antenna half, wherein the second transmission phase offset of the second antenna half offset is 180 degrees in relation to the first antenna half;and transmitting the generated electromagnetic waveform whereto the first and the second phase offsets have been applied. The present invention also relates to an electronically steerable antenna system configured to execute the method.