Shared-Aperture Phased Array Grounding to Suppress Grating Lobes
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Solution Overview
Problem
Conventional wireless devices with multiple phased array antennas face challenges due to separate printed circuit boards, leading to increased size, cost, and interference from grating lobes and under-sampling issues when different frequency bands share an aperture.
Innovation Solution
Implementing parasitic antenna elements in the lower frequency lattice to reduce grating lobe effects while maintaining good antenna performance, using dual linearly polarized elements and orthogonal polarizations to mitigate performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate printed circuit boards are used for multiple phased array antennas, then each antenna can operate independently, but the device size and PCB stack-up complexity increase
Solution Approach 1:
The patent combines multiple phased array antennas operating at different frequency bands onto a single PCB substrate. The first and second lattices of antenna elements are integrated on the same board, sharing common ground structures and support infrastructure, thereby reducing overall device complexity while maintaining independent operation of each antenna system
Solution Approach 2:
The single PCB substrate serves multiple functions by supporting both the first lattice for lower frequency band operation and the second lattice for higher frequency band operation. The unified ground plane and structural support provide universal functionality across different frequency bands, eliminating the need for separate dedicated PCBs for each antenna system
2Area of stationary object
If different frequency bands share an aperture, then device size is reduced, but grating lobe effects and under-sampling issues occur
Solution Approach 1:
The patent applies different lattice configurations to different frequency bands within the shared aperture. The first lattice is optimized for lower frequency band operation while the second lattice is optimized for higher frequency band operation. Each lattice has locally adapted element spacing and geometry tailored to its specific frequency range, allowing grating lobe suppression for each band while sharing the same physical aperture space
Solution Approach 2:
The patent resolves grating lobe issues by transitioning from a two-dimensional planar array to a three-dimensional overlaid structure. The first and second lattices are positioned at different vertical levels (z-dimension) on the PCB substrate, with the second lattice elevated above the first. This vertical separation allows both frequency bands to operate in the same aperture without mutual interference, effectively suppressing grating lobes through spatial dimensionality
3Reliability
If parasitic antenna elements are added to reduce grating lobes, then antenna performance improves, but device complexity increases
Solution Approach 1:
The patent introduces parasitic antenna elements as intermediary structures between the driven elements of the first lattice and the ground plane. These parasitic elements are not directly connected to feed networks but are strategically positioned to manipulate electromagnetic fields, suppress grating lobes, and improve overall antenna performance. They act as passive mediators that enhance system performance without requiring additional active components or complex feed structures
Data Source
AI summary
Technologies directed to overlaid shared aperture array with improved total efficiency are described. One RF structure includes a first antenna with a first set of antenna elements disposed on a first plane of a support structure and a second antenna with a second set of antenna elements disposed on a second plane of the support structure. A set of parasitic antenna elements are disposed on the first plane. Two adjacent antenna elements, including one from the first plurality of antenna elements and another one from the plurality of parasitic antenna elements, are separated by the second distance.