Multi-Layer Fringe Capacitor Time Delay Filters
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Solution Overview
Problem
Traditional time delay elements in analog circuits, such as RF transceivers, face issues like excessive size, cost, complexity, poor manufacturability, high loss, and high amplitude or phase ripple, limiting their performance.
Innovation Solution
The development of LC-resonator-based time delay filters with multi-layer fringe capacitors that provide a high quality factor, enabling frequency-invariant group delay and low insertion loss, integrated into a substrate to reduce size and cost, and allowing for adjustable and reconfigurable delay without increasing circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional delay elements (ceramic filters, SAW filters, coaxial cables) are used, then time delay function is achieved, but size becomes excessive
Solution Approach 1:
The patent transitions from traditional distributed delay structures (coaxial cables, waveguides) to a lumped-element LC resonator circuit implementation. By using multiple LC resonators with specific resonant frequencies arranged in a network, the delay function is achieved through resonant frequency selection rather than physical propagation delay, dramatically reducing the required physical size while maintaining the time delay function.
Solution Approach 2:
The patent achieves time delay by precisely controlling the resonant frequencies of LC resonators and their coupling coefficients. By adjusting these parameters (inductance L, capacitance C values, and coupling strengths), the group delay can be tuned without changing the physical dimensions of the components, allowing size reduction while maintaining delay performance.
2Loss of time
If traditional delay elements are used, then time delay function is achieved, but cost becomes excessive
Solution Approach 1:
The patent uses multiple identical or similar LC resonator units that can be manufactured using the same process and components. By replicating these standardized resonator blocks with different frequency tuning, the system achieves complex delay functions using simple, inexpensive, mass-producible components rather than expensive custom-designed traditional delay elements.
Solution Approach 2:
The patent replaces mechanical/physical delay structures (coaxial cables, ceramic filters, SAW devices) with electrical resonant circuits. This substitution allows the use of standard electronic components (inductors, capacitors, resistors) that are inexpensive and easily manufactured using conventional PCB or integrated circuit fabrication techniques.
3Loss of time
If traditional delay elements are used, then time delay function is achieved, but complexity increases
Solution Approach 1:
The patent divides the overall delay function into multiple independent LC resonator units, each operating at a specific resonant frequency. By segmenting the delay function across frequency bands and using selective coupling between resonators, the complex delay requirement is broken down into simpler, manageable modular units that can be designed and analyzed independently.
Solution Approach 2:
The patent designs a universal LC resonator module that can serve multiple functions: frequency selection, impedance matching, and time delay. The same basic resonator structure with adjusted L and C values can provide different delay characteristics, reducing the need for specialized components and simplifying the overall system design.
4Loss of time
If traditional delay elements are used, then time delay function is achieved, but loss becomes high
Solution Approach 1:
The patent uses tunable LC resonators with variable inductance or capacitance (e.g., using varactor diodes or switched capacitor networks) to dynamically adjust the resonant frequencies and coupling coefficients. This dynamic tuning capability allows optimization of the delay response to minimize insertion loss across the operating bandwidth, adapting to different signal conditions and frequency ranges.
5Loss of time
If traditional delay elements are used, then time delay function is achieved, but amplitude ripple or phase ripple becomes high
Solution Approach 1:
The patent employs feedback mechanisms through coupled resonator networks where the output of one resonator feeds back to influence the response of others. This feedback arrangement allows cancellation of amplitude and phase ripples by adjusting coupling coefficients, creating a flatter group delay response across the passband and improving signal fidelity.
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
These filters enhance the performance of RF transceivers and other systems by providing accurate, adjustable time delay with reduced size and cost, while maintaining low insertion loss and minimizing ripple, thus overcoming the limitations of traditional delay elements.
Implementation Method 1
a first set of interdigitated capacitor electrodes, an additional set of interdigitated capacitor electrodes, and a set of coupling vias that couple the first set of capacitor electrodes to the additional set of capacitor electrodes
Implementation Method 2
LC-resonator-based time delay filters with multi-layer fringe capacitors that provide a high quality factor, enabling frequency-invariant group delay
Data Source
AI summary
A multilayer fringe capacitor includes first and second interdigitated capacitor electrodes, both parallel to and intersecting a first planar surface; third and fourth interdigitated capacitor electrodes, the first and second electrodes parallel to and separated by a non-zero distance from the third and fourth electrodes; a first set of coupling vias that electrically couples the first electrode to the third electrode; and a second set of coupling vias that electrically couples the second electrode to the fourth electrode.