Vehicular LTE-5G Antenna Layout for MIMO Isolation
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Solution Overview
Problem
Existing antenna systems in vehicles struggle to provide sufficient isolation between LTE and 5G antennas while maintaining a compact size, particularly in LTE re-farming scenarios where 5G operates in sub-6 GHz or less, and there is a lack of detailed methods for ensuring adequate isolation between multiple communication systems.
Innovation Solution
A flat vehicle antenna system with optimized isolation is achieved by arranging first and second antenna elements on a circuit board, where the first antenna system performs MIMO using LTE antennas and the second system performs beam-forming using array antennas, with specific configurations such as off-center feeding and partial shifting of LTE antennas to enhance isolation, and incorporating additional antennas like C2X, WiFi, SDARS, and GNSS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If LTE and 5G antennas are arranged in a compact vehicle antenna system, then the device size is reduced and ease of installation is improved, but isolation between antennas deteriorates
Solution Approach 1:
The patent applies dimensionality change by transitioning from a planar 2D antenna arrangement to a three-dimensional configuration. The LTE antennas are positioned at the four corners of the circuit board while the 5G antenna is placed at the center, utilizing vertical spacing and radial distance to achieve isolation. This spatial distribution in multiple dimensions allows compact overall size while maintaining sufficient isolation between different communication systems.
Solution Approach 2:
The antenna system is segmented into distinct functional zones: LTE antennas are grouped at the peripheral corners for MIMO operations, while the 5G antenna occupies the central region for beam-forming. This segmentation separates the two communication systems into different spatial zones on the same circuit board, enabling compact integration while preserving isolation through functional zoning and spatial separation.
2Device complexity
If multiple antenna elements are integrated on the same circuit board, then device complexity is reduced and manufacturing is simplified, but isolation between different communication systems deteriorates
Solution Approach 1:
The patent resolves the isolation problem in integrated designs by utilizing three-dimensional spatial arrangement. The 5G antenna at the center and LTE antennas at the corners create radial separation in the planar dimension, while vertical mounting considerations provide additional isolation. This multi-dimensional positioning allows multiple antenna elements on a single circuit board to maintain sufficient isolation between LTE and 5G systems.
Solution Approach 2:
Different regions of the circuit board are assigned different functional qualities: the central region is optimized for 5G beam-forming operations, while the corner regions are optimized for LTE MIMO operations. This local quality differentiation ensures that each communication system operates in its optimal spatial zone, maintaining isolation while achieving integration on a single board.
Data Source
AI summary
An antenna system mounted in a vehicle according to the present invention may include: a first antenna system in which multiple first antenna elements configured to transmit and receive a first signal according to a first communication system perform multi-input multi-output (MIMO); and a second antenna system in which multiple second antenna elements configured to transmit and receive a second signal according to a second communication system perform beamforming, wherein the multiple first antenna elements and the multiple second antenna elements are arranged on the same circuit board, so as to provide an antenna arrangement structure in which the isolation characteristic between antenna elements is optimized, for a flat vehicular antenna including an LTE antenna system and a 5G antenna system.