AiP Antenna Isolation via Vertical Stacking
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Solution Overview
Problem
Current Antenna-in-Package (AiP) technologies for millimeter-wave automotive radar systems face challenges in achieving better antenna performance and isolation between transmit (Tx) and receive (Rx) antennas, which is crucial for efficient mmW radar applications like adaptive cruise control systems, especially under adverse weather conditions.
Innovation Solution
The proposed AiP design includes an interface layer with an antenna layer, a ground reflector layer, and an insulating layer, featuring two spaced antenna regions for Tx and Rx signals, with a feeding network and solder balls for improved electrical connections, and a molding compound for encapsulation, optimizing antenna layout and isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If antenna elements are integrated into the package substrate, then device integration is improved, but antenna performance and isolation between Tx and Rx antennas deteriorate
Solution Approach 1:
The antenna system is segmented into separate transmit and receive antenna regions on different substrates. The Tx antenna is formed on the package substrate while the Rx antenna is formed on a separate receiver integrated circuit (Rx IC) die, preventing mutual interference and improving isolation between transmit and receive paths.
Solution Approach 2:
The patent utilizes vertical stacking in the Z-direction to separate Tx and Rx antennas spatially. The Tx antenna is positioned on the package substrate in a first horizontal plane, while the Rx antenna is positioned on the Rx IC die in a second horizontal plane, creating vertical separation that improves isolation while maintaining compact integration.
2Volume of moving object
If compact AiP structure is used, then miniaturization is achieved, but antenna isolation and performance deteriorate
Solution Approach 1:
The patent employs a nested three-dimensional stacked configuration where the Rx IC die containing the Rx antenna is positioned vertically above or adjacent to the package substrate containing the Tx antenna. This nesting approach achieves miniaturization by utilizing the Z-direction for separation while maintaining compact footprint in the X-Y plane.
Solution Approach 2:
The patent transitions from planar two-dimensional antenna layout to three-dimensional stacked architecture. By separating Tx and Rx antennas in the vertical Z-direction rather than only in the horizontal plane, the design achieves both miniaturization and improved isolation simultaneously through spatial separation in multiple dimensions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances antenna performance and isolation between Tx and Rx antennas, reducing interference and improving efficiency for mmW radar systems, particularly in automotive applications like 77 GHz car radar systems.
Implementation Method 1
an antenna layer, a ground reflector layer under the antenna layer
Data Source
AI summary
An Antenna-in-Package (AiP) includes an interface layer having at least an antenna layer and an insulating layer disposed under the antenna layer. The antenna layer includes a first antenna region and a second antenna region spaced apart from the first antenna region. An integrated circuit die is disposed on the interface layer. The integrated circuit die is interposed between the first antenna region and the second antenna region. The first antenna region includes a first antenna element, a second antenna element extending along a first direction, and a feeding network electrically connecting the first antenna element and the second antenna element to the integrated circuit die. The feeding network, the first antenna element, and the second antenna element are coplanar. A plurality of solder balls is disposed on a surface of the interface layer.