Omnidirectional Antenna for Simultaneous Azimuth and Elevation DOA Estimation
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Solution Overview
Problem
Existing antenna systems for direction finding of wireless signals require complex and expensive constructions to accurately estimate both azimuth and elevation angles, often necessitating separate subsystems and additional hardware for elevation measurement.
Innovation Solution
An antenna system comprising a first and second omnidirectional antenna, where the first antenna transforms incoming signals into output signals with phases proportional to both azimuth and elevation angles, and the second antenna generates a reference signal with a zero phase-slope, allowing for the extraction of phase differences that include components of both angles, enabling simultaneous estimation of azimuth and elevation using simple algebraic operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two different subsystems (multimodal antenna and interferometry antenna) are used to estimate azimuth and elevation separately, then measurement precision of both angles is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the functions of azimuth and elevation estimation into a single omnidirectional antenna by utilizing spherical wave expansion. The antenna system processes both angular dimensions simultaneously through a unified signal processing framework, eliminating the need for separate multimodal and interferometry antenna subsystems while maintaining measurement precision for both azimuth and elevation angles.
Solution Approach 2:
The omnidirectional antenna is designed to perform multiple functions: it simultaneously estimates both azimuth and elevation angles, and can operate across multiple frequency bands. The single antenna structure replaces what previously required two specialized antenna subsystems, achieving multi-functionality without increasing device complexity.
2Measurement precision
If separate techniques (multimodal and interferometry) are used to extract azimuth and elevation, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent merges the extraction of azimuth and elevation into a single processing pipeline using spherical wave expansion coefficients. Instead of implementing two separate technique chains (multimodal for azimuth, interferometry for elevation), the system uses one unified technique that simultaneously provides both angular measurements, significantly simplifying the manufacturing and integration process.
3Measurement precision
If two multimodal antennas are used to produce zero mode and first-order phase mode, then measurement precision of azimuth is improved, but quantity of components increases
Solution Approach 1:
The patent extracts the azimuth estimation function from a dedicated multimodal antenna and integrates it into the spherical wave expansion processing of a single omnidirectional antenna. By taking out the azimuth extraction requirement and embedding it in the general signal processing framework, the system eliminates the need for separate multimodal antenna hardware while preserving measurement precision.
Solution Approach 2:
The single omnidirectional antenna is designed to universally handle both azimuth and elevation measurements, replacing what previously required two specialized antennas. This multi-functional approach reduces the quantity of antenna elements from two multimodal antennas to one omnidirectional antenna.
Data Source
AI summary
An antenna system for estimating the DOA of arriving signals, comprising: a first omnidirectional antenna; and a second omnidirectional antenna, which is located coaxially above the first omnidirectional antenna at a predefined distance D. The first omnidirectional antenna is configured to transform the received arriving signal into output signals, and the second omnidirectional antenna is configured to transform the received signal into a reference signal. The antenna system allows extracting: a first phase difference between the phase of the first output signal and the reference phase and a second phase difference between the phase of the second output signal and the reference phase, where each phase difference includes a first component proportional to the azimuth of said arriving signal and a second component corresponding to the elevation of the arriving signal, from which the azimuth and the elevation of the arriving signal can be extracted.