Mode Converter Pin Exposure for Impedance Matching
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Solution Overview
Problem
Conventional mode converters face challenges in impedance matching due to fixed substrate thickness, difficulty in adjusting pin length, and positional inaccuracies, leading to increased reflection loss and manufacturing complexity.
Innovation Solution
The mode converter design exposes the end of the pin on the substrate's surface, allowing for easy adjustment and confirmation of the pin's position relative to the ground conductor layer, with a cylindrical pin and anti-pad configuration to manage stress and prevent particle ingress, and a single piercing process for through-hole formation to enhance manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the substrate thickness is fixed and vias are formed in advance, then the manufacturing process is simplified, but the pin length cannot be adjusted and impedance matching precision deteriorates
Solution Approach 1:
The pin structure is designed to extend through the entire substrate thickness from the first main surface to the second main surface, allowing the effective pin length to be dynamically adjusted by controlling the exposure length at the second main surface. This enables impedance matching optimization while maintaining a fixed substrate thickness, resolving the contradiction between manufacturing simplicity and matching precision.
2Adaptability or versatility
If multiple substrates are stacked to form the pin, then the pin length can be adjusted, but the manufacturing complexity increases
Solution Approach 1:
The pin is formed as a single continuous conductive structure through one substrate rather than stacking multiple substrates. The through-hole is formed in a single piercing operation, and the conductive layer is deposited in one continuous process, eliminating the complexity of multi-substrate alignment and bonding while maintaining pin length adjustability through exposure control.
3Strength
If the pin is completely embedded in the substrate, then the structural integrity is improved, but the positional accuracy and adjustment capability deteriorate
Solution Approach 1:
The pin is partially exposed at the second main surface rather than being completely embedded. This partial exposure provides visual and physical access for positional verification and adjustment while the majority of the pin remains embedded to maintain structural integrity. The exposure length can be optimized to balance these two requirements.
4Ease of manufacture
If conventional piercing methods are used for through-hole formation, then the process is straightforward, but the positional deviation and transmission loss increase
Solution Approach 1:
Conventional mechanical piercing methods are replaced with laser piercing technology. The laser beam provides precise positioning control, minimal positional deviation, and clean hole formation without mechanical contact. This substitution maintains process simplicity while dramatically improving transmission loss characteristics and positional accuracy.
Data Source
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AI summary
A mode converter includes a substrate including a first main surface and a second main surface, a first ground conductor layer formed on the first main surface, a second ground conductor layer formed on the second main surface, a plane circuit that is formed on the first main surface and propagates a high frequency, a pin that is connected to the plane circuit, is formed inside a through-hole which penetrate from the first main surface to the second main surface, and communicates with the first main face and the second main surface, and an anti-pad that is formed between an end portion of the pin exposed in the second main surface and the second ground conductor layer.