Fishbone Stepped Impedance Resonator for Compact Chip Layout
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Solution Overview
Problem
The existing resonators, such as stepped impedance resonators (SIRs), require a long chip shape due to their linear configuration, restricting chip shape and pattern design due to the large footprint, and introducing curved or fishbone waveguides complicates the design and increases the risk of unwanted resonance modes.
Innovation Solution
A resonator configuration that includes a coplanar waveguide with a first impedance and a section with a second impedance, utilizing a fishbone waveguide connected in series, allowing for a stepped impedance resonator that reduces the footprint by inserting a fishbone waveguide between curved waveguides, thereby shortening the longitudinal dimension and improving design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear coplanar waveguide with length of the same order as the wavelength is used to form a distributed constant type SIR, then the resonator can achieve the desired resonance frequency, but the chip footprint becomes large and design flexibility is restricted
Solution Approach 1:
The patent transforms the linear one-dimensional waveguide layout into a two-dimensional fishbone structure with multiple branches extending perpendicular to the main transmission line. This dimensional change allows the resonator to achieve the required electrical length for resonance while occupying significantly less chip area, as the signal path folds back on itself in the transverse direction rather than extending linearly.
Solution Approach 2:
The waveguide is segmented into multiple sections with different impedance values (first impedance and second impedance sections) arranged in a stepped configuration. This segmentation allows the resonator to achieve the desired resonance characteristics through distributed impedance transformation while maintaining a compact footprint, as each segment contributes to the overall resonance without requiring the full linear wavelength length.
2Area of stationary object
If curved or fishbone waveguides are introduced to reduce footprint, then the chip area is reduced, but the design becomes more complicated and the risk of unwanted resonance modes increases
Solution Approach 1:
The patent applies different impedance characteristics to different local sections of the waveguide (first impedance coplanar waveguide sections and second impedance sections with different geometric configurations). This local differentiation of properties allows the resonator to achieve compact sizing through impedance transformation while maintaining controlled impedance throughout the structure, reducing the risk of unwanted resonance modes through proper impedance matching at each section transition.
3Measurement precision
If a long linear chip shape is used for the resonator, then the resonance frequency can be accurately controlled, but the chip shape and pattern design are restricted due to large area occupation
Solution Approach 1:
The patent employs a fishbone-like two-dimensional waveguide layout where multiple parallel waveguide sections extend in directions perpendicular to the main transmission path. This dimensional transformation enables accurate resonance frequency control through precise impedance matching in each section while providing great flexibility in chip shape and pattern design, as the resonator can be configured to fit various layout requirements without requiring a long linear footprint.
Data Source
AI summary
An object is to provide a stepped impedance resonator capable of efficiently reducing a footprint. A resonator includes a coplanar waveguide and a section. The coplanar waveguide has a first impedance. The section has a second impedance different from the first impedance and includes a fishbone waveguide. The resonator is configured as a stepped impedance resonator in which the coplanar waveguide and the section including the fishbone waveguide are connected in series.