Stepped-Substrate High-Frequency Terminator for Low-Reflection Matching
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Solution Overview
Problem
In high-frequency circuits, existing termination structures face challenges in suppressing reflections of high-frequency signals due to inductance from connection conductors or through-holes, which limits bandwidth.
Innovation Solution
A high-frequency terminator design featuring a dielectric substrate with varying thicknesses and a step in the back surface, a microstrip transmission line connected to a resistor, and a conductor linking the resistor to a metal layer on the back surface, optimizing impedance and reducing reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a connection conductor or through-hole is used to connect the resistor to the back surface, then electrical connection is achieved, but inductance increases causing impedance increase and signal reflections in high-frequency band
Solution Approach 1:
The patent removes the connection conductor or through-hole from the termination structure, extracting the harmful inductive element while maintaining the essential electrical connection function through alternative means that do not introduce significant inductance.
Solution Approach 2:
The patent changes the physical parameters of the termination structure by using a thin-film resistor with specific resistance value and thickness, and by optimizing the layout of the resistor terminals to minimize loop area, thereby reducing inductance without requiring traditional connection conductors.
2Reliability
If the dielectric substrate thickness is reduced to minimize inductance, then high-frequency performance improves, but mechanical strength decreases
Solution Approach 1:
The patent applies different thicknesses of dielectric substrate in different regions: a thinner region under the resistor to minimize inductance and improve high-frequency performance, and a thicker region in other areas to maintain mechanical strength and provide adequate support for the overall structure.
Data Source
AI summary
A high-frequency terminator includes a dielectric substrate, a metal layer provided on a back surface of the dielectric substrate, a transmission line provided on a front surface of the dielectric substrate, a resistor provided on the front surface of the dielectric substrate and connected to the transmission line, and a conductor electrically connecting the resistor and the metal layer. The dielectric substrate includes a first substrate part having a first thickness in a direction from the back surface toward the front surface, and a second substrate part having a second thickness in the direction that is less than the first thickness. The transmission line extends from the first substrate part to the second substrate part and is connected to the resistor on the second substrate part. The conductor electrically connects the metal layer and the resistor at the second substrate part.