Dual Frequency Antenna Element Spacing for Wide Scan Range
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Solution Overview
Problem
AESA radar systems face scan loss and reduced effectiveness when scanning at extreme angles due to beam broadening, and increasing scan range through more antenna elements or multiple AESAs results in increased size, weight, and cost.
Innovation Solution
Operating a single AESA radar system at two distinct frequencies to create a faux planar aperture, allowing for wider scan ranges without adjusting amplitude or phase values, and relaxing antenna element spacing to reduce the number of elements required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of antenna elements is increased to extend scan range, then scan coverage is improved, but size, weight, and cost increase
Solution Approach 1:
The patent changes the operating frequency parameter of the AESA system to achieve extended scan range. By operating at two different frequencies (first and second frequencies), the system creates a faux planar aperture that enables scanning to extreme angles without physically increasing the number of antenna elements, thus avoiding the weight penalty associated with larger arrays.
2Adaptability or versatility
If the number of antenna elements is increased to extend scan range, then scan coverage is improved, but system cost increases
Solution Approach 1:
The invention utilizes frequency parameter changes rather than physical array expansion. By switching between two operating frequencies, the system achieves wider scan coverage without the prohibitive cost of manufacturing and deploying additional antenna elements or multiple AESA units.
3Device complexity
If antenna element spacing is increased to reduce element count, then system complexity is reduced, but grating lobes are generated
Solution Approach 1:
The patent applies frequency parameter changes to resolve the grating lobe issue. By operating at two distinct frequencies with appropriately spaced boresight positions, the system can use larger element spacing without generating harmful grating lobes within the desired scan volume. The dual-frequency operation creates a faux planar aperture that eliminates grating lobe problems.
Data Source
AI summary
Systems and methods described herein are directed towards a radar system and a dual frequency electronically scanned array (ESA) capable of transmitting and receiving radio frequency (RF) signals at least two frequencies. The ESA includes a plurality of antenna elements which form a first effective aperture at a first radio frequency (RF) frequency and operational over a first scan range and which form a second effective aperture at a second radio frequency (RF) frequency and operational over a second scan angle. The first and second scan ranges are complementary so as to provide the radar system having an overall scan range. The plurality of antenna elements are spaced apart from each other by an amount related to at least one of the first and second scan ranges and/or one or more operating frequencies of the radar system.