Circular Monopulse Antenna Array for Direction Finding
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Solution Overview
Problem
Existing antenna arrays face challenges in determining the direction-of-arrival of wireless signals efficiently due to complexity and size, particularly in obtaining omnidirectional antennas and accurately tracking fast-changing signal directions.
Innovation Solution
A mono-pulse scheme is applied to a circular antenna array with equally spaced antenna elements, where signals from adjacent elements are split, processed using summation and differencing, and a ratio is calculated to determine the angle of arrival, utilizing simplified architecture and processing to track changing directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional antenna arrays use omnidirectional antennas arranged in symmetrical patterns, then direction finding capability is achieved, but system complexity and size increase significantly
Solution Approach 1:
The patent divides the antenna array into distinct functional segments: a reference antenna and multiple sensing antennas. Each sensing antenna processes signals independently through sum and difference channels, breaking down the complex omnidirectional array into manageable modular units that can be processed separately and combined for direction finding
Solution Approach 2:
The patent transitions from traditional planar array geometries to a three-dimensional configuration where sensing antennas are positioned at specific heights and radial distances from the reference antenna. This vertical dimension addition enables direction finding without requiring complex horizontal symmetrical patterns, reducing overall system complexity
2Reliability
If antenna elements are arranged in symmetrical patterns for reinforcement and cancellation, then signal processing effectiveness is improved, but manufacturing and deployment difficulty increases
Solution Approach 1:
The patent deliberately employs asymmetric antenna positioning where sensing antennas are located at specific radial distances and heights rather than in symmetrical patterns. The asymmetric configuration uses weighted combinations of sum and difference channels with carefully selected coefficients to achieve the desired signal reinforcement and cancellation effects without requiring symmetrical geometric arrangements
Solution Approach 2:
The patent changes the physical parameters of antenna placement (radial distance, height, angular position) and signal processing parameters (weighting coefficients, phase shifts) to optimize direction finding performance. By adjusting these parameters rather than relying on fixed symmetrical patterns, the system achieves reliable signal processing while simplifying manufacturing and deployment
3Measurement precision
If complex processing is used to determine angle of arrival from signal differences, then measurement accuracy is improved, but processing time increases
Solution Approach 1:
The patent pre-calculates and stores optimal weighting coefficients and phase shift values that correspond to different arrival angles. During operation, the system simply retrieves these pre-computed values and applies them to the sum and difference channel outputs, avoiding complex real-time calculations and significantly reducing processing time while maintaining accurate angle of arrival measurement
Solution Approach 2:
The patent introduces sum and difference channels as intermediary processing stages between the antenna elements and the final angle determination. These intermediaries transform the raw antenna signals into simplified representations that contain the essential direction information, reducing the computational burden of subsequent processing while preserving measurement accuracy
4Measurement precision
If multiple antenna elements are used for direction tracking, then tracking accuracy for fast-changing directions is improved, but system cost increases
Solution Approach 1:
The patent segments the direction finding function into a minimal set of antenna elements (one reference and a few sensing antennas) rather than using large arrays. Each antenna performs a specific function in the tracking process, reducing the total number of elements required while maintaining adequate tracking accuracy for fast-changing directions through optimized signal processing
Solution Approach 2:
The patent implements dynamic signal processing that adapts to fast-changing signal directions by continuously updating the angle of arrival estimates using the most recent sum and difference channel measurements. This dynamic approach allows accurate tracking of rapidly moving targets with fewer antenna elements compared to static traditional arrays
Data Source
AI summary
Provided herein is a compact and economical direction finding antenna using a mono-pulse antenna system, where a plurality of antenna elements are disposed in a circular array. The directional antennas may be formed by any type of antenna element, including a patch or reflector. The antenna beams of the directional antenna elements overlap, so that from any azimuthal direction, the point is covered by more than one antenna beam. Signals from each pair of adjacent antenna elements of the circular array are processed in order to determine the angle of arrival of a received signal.