Multilayer Dielectric Substrate Cavity Resonance Suppression
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Solution Overview
Problem
Conventional high-frequency semiconductor packages struggle to suppress cavity resonance effectively for multiple signal frequencies, as existing configurations only address resonance for a single frequency, leading to instability in semiconductor device operation and transmission lines.
Innovation Solution
A multilayer dielectric substrate is designed with a pseudo open state termination waveguide, featuring impedance transformers, tip-short-circuited dielectric transmission lines, and resistors strategically placed to maximize electric field distribution and absorption, effectively suppressing cavity resonance for multiple frequencies without increasing costs or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional impedance transformer and dielectric transmission lines are provided for only one frequency, then resonance of target frequency can be suppressed, but resonance of frequencies other than target frequency cannot be suppressed
Solution Approach 1:
The patent applies universality by designing a single impedance transformer structure that can suppress cavity resonance across multiple frequencies simultaneously. The impedance transformer is configured with specific dimensional relationships (length being 1/4 of effective wavelength) and impedance values that enable it to function effectively for both fundamental and harmonic frequencies, making one component serve multiple frequency suppression functions rather than requiring separate components for each frequency
Solution Approach 2:
The patent utilizes parameter changes by optimizing the impedance transformer's physical dimensions and impedance characteristics. The length of the impedance transformer is set to 1/4 of the effective wavelength of the signal wave, and its characteristic impedance is specifically calculated based on the cavity dimensions and signal frequency. These parameter adjustments enable the transformer to suppress resonance at the target frequency and its harmonics without requiring additional components
2Productivity
If cavity size is increased to accommodate multiple high frequency circuits, then device integration is improved, but cavity resonance becomes more likely to be generated
Solution Approach 1:
The patent applies the extraction principle by removing the cover from the cavity, transforming it from a closed resonant cavity into an open-ended waveguide structure. This extraction of the cover eliminates the standing wave conditions that cause cavity resonance, allowing the cavity to accommodate multiple devices at higher frequencies without resonance issues. The opening is then terminated with an impedance transformer to maintain proper signal integrity
3Reliability
If impedance transformer length is set to 1/4 of in-substrate effective wavelength, then impedance matching is improved, but structural complexity increases
Solution Approach 1:
The patent applies merging by integrating the impedance transformer directly into the existing transmission line structure of the substrate. The transformer is formed as a continuous conductive pattern on the substrate layer, merging the impedance transformation function with the signal transmission function. This eliminates the need for separate discrete components or complex multi-layer structures, achieving impedance matching while maintaining structural simplicity
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 solution achieves reliable suppression of cavity resonance for multiple signal frequencies, ensuring stable operation of semiconductor devices and transmission lines with minimal reflection and maximum attenuation, thereby enhancing operational stability.
Implementation Method 1
an impedance transformer with a length of an odd multiple of about 1/4 of in-substrate effective wavelength λg of a signal wave is formed in the dielectric substrate beyond the opening
Implementation Method 2
A resistor (a printed resistor) is then formed to cover the coupling aperture
Implementation Method 3
a tip-short-circuited dielectric transmission line with a length of an odd multiple of about 1/4 of in-substrate effective wavelength λg of a signal wave is formed beyond the coupling aperture
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A multilayer dielectric substrate includes a first cavity-resonance suppressing circuit 20A that suppresses cavity resonance of a first signal wave and a second cavity-resonance suppressing circuit 20B that suppresses cavity resonance of a second signal wave, a frequency thereof being different from that of the first signal wave. These cavity-resonance suppressing circuits respectively include openings 50A and 50B formed in a surface-layer ground conductor 18, an impedance transformer with a length of an odd multiple of about 1/4 of in-substrate effective wavelength of a signal wave, a tip-short-circuited dielectric transmission line with a length of an odd multiple of about 1/4, a coupling aperture formed in an inner-layer ground conductor, and a resistor formed in the coupling aperture. Accordingly, a multilayer dielectric substrate that suppresses cavity resonance of signal waves of a plurality of frequencies can be obtained.