Array Antenna Substrate Joining with Matched Thermal Expansion
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Solution Overview
Problem
Existing array antenna apparatus face challenges in reducing size while maintaining antenna characteristics due to substrate warpage and positional misalignment issues caused by differences in material coefficients of expansion and thermal distortion when joining substrates of varying materials and sizes.
Innovation Solution
The array antenna apparatus is designed with a wiring substrate having fed patch antennas and active element circuits, and multiple antenna substrates with parasitic patch antennas are joined onto this wiring substrate, reducing the size and positional misalignment by using a fluororesin-based high-frequency printed circuit board with low dielectric loss and precise alignment techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If substrates of different materials are joined to reduce size, then device compactness is improved, but substrate warpage and positional misalignment occur due to different coefficients of linear expansion
Solution Approach 1:
The patent changes the material parameter (coefficient of linear expansion) by selecting a resin substrate with a coefficient matching that of the ceramic substrate. This parameter matching prevents differential thermal expansion during joining and operation, eliminating warpage and positional misalignment while enabling compact device design.
Solution Approach 2:
The patent applies homogeneity by ensuring that the resin substrate and ceramic substrate have matching thermal expansion characteristics. This creates homogeneous thermal behavior across the joined structures, preventing the heterogeneous expansion that causes warpage and alignment errors in multi-material assemblies.
2Productivity
If large area substrates are joined, then more antenna elements can be accommodated, but warpage and torsion occur due to heat applied during joining or emitted during use
Solution Approach 1:
The patent changes the thermal expansion parameter of the substrate system by using a resin substrate with matching expansion characteristics. This allows large-area substrates to be joined and operated without warpage or torsion, maintaining shape stability while accommodating multiple antenna elements.
3Adaptability or versatility
If substrates with different electric elements or wiring patterns are used, then functional versatility is improved, but different coefficients of linear expansion cause warpage and distortion
Solution Approach 1:
The patent changes the material parameter (coefficient of linear expansion) to be consistent across substrates with different functional elements. This allows diverse antenna configurations and wiring patterns to be implemented on different substrates that, when joined, maintain positional accuracy due to matched thermal expansion characteristics.
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 allows for a compact array antenna apparatus with improved antenna characteristics by minimizing warpage, torsion, and distortion, thereby maintaining accurate positional alignment and enhancing radiation efficiency and frequency bandwidth.
Implementation Method 1
using a fluororesin-based high-frequency printed circuit board with low dielectric loss
Implementation Method 2
differences in material coefficients of expansion and thermal distortion when joining substrates
Data Source
AI summary
An array antenna apparatus includes: a wiring substrate having a plurality of fed patch antennas and a plurality of active element circuits electrically connected to the plurality of fed patch antennas, respectively; and a plurality of antenna substrates each having a parasitic patch antenna. The plurality of antenna substrates are joined onto one wiring substrate. Thereby, it becomes possible to provide an array antenna apparatus that can be reduced in size and has excellent antenna characteristics.