Staircase Post Wall Waveguide Layout for Better RF Transmission
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Solution Overview
Problem
The existing post wall waveguide has suboptimal radio wave transmission characteristics due to its shape being close to a rectangular waveguide.
Innovation Solution
A wiring board design incorporating a built-in post wall waveguide with a staircase-shaped laminate of via interconnects across multiple insulating layers, where the intervals between adjacent via interconnects are varied to resemble a circular waveguide configuration, improving transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the post wall waveguide is formed with via interconnects arranged in a rectangular pattern, then the manufacturing process is simple, but the radio wave transmission characteristics are suboptimal
Solution Approach 1:
The patent applies the spheroidality principle by transitioning from a rectangular via interconnect arrangement to a circular pattern. The via interconnects are arranged in a circular configuration rather than a rectangular grid, which transforms the waveguide's cross-sectional shape from rectangular to circular. This curvature change improves radio wave transmission characteristics by reducing impedance discontinuities and improving field distribution, while the circular pattern can still be manufactured using standard via drilling and plating processes.
2Reliability
If the interval between adjacent via interconnects is uniform, then the manufacturing precision is easier to maintain, but the transmission characteristics are degraded
Solution Approach 1:
The patent applies the local quality principle by implementing non-uniform spacing of via interconnects within the circular arrangement. Specifically, the spacing between adjacent via interconnects varies depending on their position in the circular pattern. This local variation in spacing is optimized to improve transmission characteristics by better matching impedance and reducing reflections, while each local spacing value can still be controlled within standard manufacturing tolerances.
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
The modified waveguide structure enhances radio wave transmission by mimicking a circular waveguide shape, leading to improved transmission characteristics compared to traditional rectangular waveguide designs.
Implementation Method 1
serving as a transmission path for electromagnetic waves
Data Source
AI summary
A wiring board has a built-in post wall waveguide having a region surrounded by two mutually opposing conductors and first and second post walls connecting the two conductors and serving as a transmission path for electromagnetic waves. The conductors oppose each other with insulating layers interposed therebetween. The first post wall has first columnar portions, formed by a laminate of via interconnects penetrating the insulating layers, arranged at predetermined intervals in a first direction in which the electromagnetic waves are transmitted. The second post wall has second columnar portions similar to the first columnar portions. In a cross sectional view taken in a second direction perpendicular to the first direction, an interval between adjacent via interconnects in one of the insulating layers not in contact with the conductor is wider than an interval between adjacent via interconnects in two of the insulating layers in contact with the two conductors, respectively.