Phased Array Antenna Dynamic Thinning for Interference Rejection
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Solution Overview
Problem
Existing array antennas face challenges in efficiently adapting their beam patterns to reject interfering signals due to the impracticality of digital beamforming for large arrays, which results in difficulty in selecting optimal null locations for sidelobes, leading to suboptimal signal-to-noise ratios.
Innovation Solution
An array antenna system dynamically reconfigures its beam pattern by applying different thinning patterns to alter the location of sidelobes and nulls, using a controller to selectively turn off antenna elements and adjust the taper pattern, with methods including genetic algorithms to identify improved signal-to-noise ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital beamforming is used to place nulls in the direction of interfering signals, then the signal to noise ratio is improved, but the hardware and software cost becomes impractical for large arrays
Solution Approach 1:
The patent extracts only the essential function of null placement from complex digital beamforming by using simple on/off switching of antenna elements. This eliminates the need for complex digital signal processing hardware while achieving the same interference rejection goal through geometric thinning patterns that create nulls in specific directions.
Solution Approach 2:
The patent replaces expensive, complex digital beamforming hardware with simple, inexpensive element switching mechanisms. The thinning patterns use basic on/off states of antenna elements rather than requiring sophisticated digital signal processing equipment, making the system practical for large arrays.
2Strength
If a fixed beam pattern is used to attenuate sidelobes, then the main beam gain is maintained, but the ability to dynamically reject interfering signals is limited
Solution Approach 1:
The patent transforms the static beam pattern into a dynamic system by enabling real-time switching between multiple thinning patterns. Each pattern creates different null locations, allowing the antenna to adapt its interference rejection characteristics dynamically while preserving the main beam through proper pattern selection and combination.
Solution Approach 2:
The patent changes the geometric configuration parameters of the antenna array by applying different thinning patterns that alter element spacing and distribution. These parameter changes create different spatial frequency responses, enabling nulls to be placed at various angles to track and reject moving or multiple interfering signals.
3Reliability
If antenna elements are turned off to create thinning patterns, then null locations are improved for interference rejection, but the overall gain of the antenna is reduced
Solution Approach 1:
The patent applies partial thinning by turning off only a subset of antenna elements rather than the entire array, creating sufficient null depth for interference rejection while maintaining adequate overall gain. The selective application of thinning patterns to specific angular regions allows interference suppression without excessive loss of main beam power.
Data Source
AI summary
Methods and systems for thinning the output of an array antenna are disclosed. The thinning can be applied in response to determining that the performance of a multiple element antenna array with respect to a desired signal has been compromised by the presence of one or more interfering signals. The application of a thinning pattern has the effect of turning off selected antenna elements within the array. The effect of applying a particular thinning pattern on the realized performance of the antenna system can be determined. An alternate thinning pattern can be applied if the previous thinning pattern did not result in an improvement, or a sufficient improvement, in the performance of the antenna system.