SIW-Coupled SSS Low-Pass Filter With Integrated Notch Response
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Solution Overview
Problem
The integration of Suspended Substrate Stripline (SSS) Low Pass Filters (LPFs) with Substrate Integrated Waveguide (SIW) cavity resonators to produce a notch response is challenging due to the bulkiness of SSS to SIW transitions, which complicates the integration of both structures.
Innovation Solution
The integration of a SIW cavity resonator with a SSS LPF, where the SIW cavity is coupled to the SSS filter circuit using a plurality of vias forming parallel rows and controlled coupling through openings, allowing for a notch response in the passband or transition band, with the size of the SIW cavity determining the notch placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a SSS LPF is cascaded with a SIW cavity notch filter to produce a notch response, then the rejection characteristics are improved, but the integration becomes bulky and complex
Solution Approach 1:
The patent combines the SSS LPF and SIW cavity resonator into a single integrated structure where the SIW cavity is formed directly on the same substrate as the SSS filter circuit. The coupling is achieved through shared ground references and electromagnetic field interaction, eliminating the need for separate cascaded components and reducing overall device complexity while maintaining notch response functionality.
Solution Approach 2:
The patent introduces a coupling mechanism using shared ground planes and electromagnetic field coupling as intermediaries between the SSS LPF and SIW cavity. This intermediary coupling method allows energy transfer and notch response generation without requiring direct physical connection or bulky transition structures, thereby simplifying the integration.
2Reliability
If a SSS LPF is cascaded with a SIW cavity notch filter, then a notch response is achieved, but the transition structure becomes bulky
Solution Approach 1:
The patent merges the SSS LPF and SIW cavity resonator onto the same substrate, eliminating the need for separate transition structures. The SIW cavity is formed using vias and metal plates integrated with the SSS filter substrate, creating a compact unified structure that achieves notch response without bulky transitions.
Solution Approach 2:
The patent utilizes the vertical dimension by forming the SIW cavity between top and bottom ground plates on the substrate, allowing the resonator to be integrated in the thickness direction rather than requiring lateral expansion. This dimensional approach reduces the overall footprint and eliminates bulky transition structures.
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 enhances the rejection characteristics by creating a notch response, improving the filter's performance in terms of low insertion loss and out-of-band rejection, while maintaining a compact design by integrating both structures on the same substrate.
Implementation Method 1
A Substrate Integrated Waveguide (SIW) cavity resonator is coupled to the filter circuit to create a notch response in the SSS filter
Data Source
AI summary
A Substrate Integrated Wave (SIW) coupled to a Suspended Substrate Stripline (SSS) filter for introducing a notch response has a substrate having metal layers formed on a top surface and a bottom surface thereof. A filter circuit is formed on the top surface of the substrate. A top ground plate is provided and has an air cavity formed on a bottom surface of the top ground plate. The air cavity on the top ground plate is positioned directly above the filter circuit when the top ground plate is positioned on the top surface of the substrate. A bottom ground plate is provided and has an air cavity formed on a top surface of the bottom ground plate. The air cavity on the bottom ground plate is positioned directly below the filter circuit when the bottom ground plate is positioned on the bottom surface of the substrate. A SIW cavity resonator is coupled to the filter circuit by means of an aperture to create a notch response in the SSS filter.