Logarithmic Spiral Antenna for Compact Angle-of-Arrival Sensing
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Solution Overview
Problem
Conventional direction-finding systems are large, heavy, and lack accuracy due to their reliance on arrays of antennas spaced far apart to determine the angle of arrival of electromagnetic waves, which is undesirable for applications like aircraft navigation.
Innovation Solution
An antenna with a logarithmic spiral geometry that induces a variable phase shift based on the angular position of incoming electromagnetic radiation, allowing for precise angle-of-arrival determination using a comparison with a phase-reference signal from a closely located antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional direction-finding systems use arrays of antennas spaced far apart to determine angle of arrival, then measurement precision is improved, but device complexity and weight increase
Solution Approach 1:
The patent changes the geometric parameter of the antenna structure from conventional linear or planar arrays to a logarithmic spiral configuration. This parameter change allows the antenna to produce a variable phase response across different angular positions, enabling angle of arrival determination with a single antenna element rather than requiring multiple spaced elements. The spiral geometry creates inherent phase differences that correlate with the angle of arrival, resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If conventional direction-finding systems use arrays of antennas spaced far apart, then angle of arrival accuracy is improved, but weight of the system increases
Solution Approach 1:
The patent merges the functions of multiple antenna elements into a single logarithmic spiral antenna structure. Instead of requiring multiple physically separated antenna elements to create phase differences for angle determination, the spiral geometry inherently produces the necessary phase variations across its structure. This consolidation eliminates the need for multiple discrete antenna components, support structures, and associated electronics, thereby significantly reducing the overall weight while maintaining angle of arrival measurement capability.
3Measurement precision
If conventional direction-finding systems use extensive antenna arrays, then direction-finding accuracy is improved, but drag on aircraft increases
Solution Approach 1:
The patent employs a logarithmic spiral geometry that can be integrated into a streamlined, aerodynamic form factor suitable for aircraft mounting. The curved, spiral configuration allows the antenna to be embedded within or mounted on the aircraft fuselage in a manner that minimizes disruption to airflow, unlike rigid linear arrays that create significant drag. The curved geometry naturally conforms to aerodynamic shaping requirements, reducing form drag while maintaining the phase-response characteristics necessary for accurate direction finding.
4Adaptability or versatility
If conventional direction-finding systems use multiple antennas in different quadrants, then direction determination capability is improved, but device complexity increases
Solution Approach 1:
The logarithmic spiral antenna provides omnidirectional coverage and produces a variable phase response that varies with the angle of arrival from any direction in the azimuth plane. This single antenna structure performs the function that would otherwise require multiple quadrant-specific antenna elements, each optimized for specific directional ranges. The spiral geometry inherently provides 360-degree coverage with continuous phase variation, making the system universally applicable for determining angles of arrival from any direction without requiring complex multi-quadrant configurations.
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 accurate and compact direction-finding with reduced weight and drag, providing high precision in determining the angle of arrival of electromagnetic waves without the need for extensive antenna arrays.
Implementation Method 1
The antenna geometry is configured to cause a variable phase shift in the electromagnetic radiation based on an angular position of a direction of propagation of the electromagnetic radiation relative to azimuth
Data Source
AI summary
An antenna includes antenna structure configured to receive electromagnetic radiation and including an antenna geometry. The antenna geometry is configured to cause a variable phase shift in the electromagnetic radiation based on an angular position of a direction of propagation of the electromagnetic radiation relative to azimuth. An angle-of-arrival sensor includes the antenna configured to the receive electromagnetic radiation and to produce a phase-shift signal. A method for determining an angle of arrival of electromagnetic radiation uses the angle-of-arrival sensor.