Integrated LC Tank Layout for Third-Harmonic Trapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional integrated LC tanks face challenges in suppressing third-order harmonic components without introducing insertion loss, occupying excessive layout area, or adversely affecting the fundamental frequency response.
Innovation Solution
An integrated LC tank design featuring a primary 8-shape inductor and a serial LC network laid out in a multi-layer structure on a substrate, with symmetry to mitigate magnetic coupling, allowing for high impedance at the fundamental frequency and low impedance at the third harmonic frequency, thus effectively trapping the third-order harmonic component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a 3rd order harmonic filter is used to suppress the third order harmonic component, then the third order harmonic component is suppressed, but the filter introduces appreciable insertion loss to the current signal
Solution Approach 1:
The patent merges the harmonic suppression function directly into the LC tank structure by adding a third harmonic trap (series LC circuit) that is magnetically coupled to the main inductor. This integration allows the tank to simultaneously provide high impedance at the fundamental frequency and low impedance at the third harmonic frequency without requiring a separate filter stage, thereby avoiding the insertion loss that would be introduced by an independent filter.
Solution Approach 2:
The patent utilizes magnetic coupling between the main inductor and the third harmonic trap inductor, creating a new dimension of interaction through mutual inductance. By adjusting the coupling coefficient, the system can selectively suppress the third harmonic while maintaining the fundamental frequency signal, achieving harmonic rejection without the need for direct series or parallel filtering that would cause insertion loss.
2Object-generated harmful factors
If a 3rd order harmonic filter is used to suppress the third order harmonic component, then the third order harmonic component is suppressed, but the filter occupies appreciable layout area
Solution Approach 1:
The harmonic suppression functionality is merged into the existing LC tank footprint by sharing the inductor structure. The third harmonic trap inductor is magnetically coupled to the main inductor and can be positioned within or adjacent to the same layout area, significantly reducing the total area compared to a separate filter implementation.
Solution Approach 2:
The LC tank structure is designed to serve multiple functions simultaneously: it acts as the resonant circuit for the fundamental frequency and also provides harmonic suppression through the coupled third harmonic trap. This multi-functionality eliminates the need for dedicated filter area, as the same spatial region serves dual purposes.
3Object-generated harmful factors
If a 3rd order harmonic filter is used to suppress the third order harmonic component, then the third order harmonic component is suppressed, but there is strong interaction between the filter and the integrated LC tank that adversely impacts the response at the fundamental frequency
Solution Approach 1:
The third harmonic trap is designed with specific local characteristics (inductance and capacitance values tuned for 3x the fundamental frequency) that enable it to selectively affect only the third harmonic frequency. The magnetic coupling coefficient is optimized to provide strong suppression at the third harmonic while having minimal impact on the fundamental frequency response, achieving frequency-selective harmonic rejection.
Solution Approach 2:
The resonant frequency of the third harmonic trap is set to exactly three times the fundamental frequency by carefully selecting the L and C values. This parameter configuration ensures that the trap presents low impedance only at the third harmonic frequency, allowing the fundamental frequency signal to pass through the LC tank unaffected while the third harmonic is suppressed.
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 design achieves high impedance at the fundamental frequency while maintaining low impedance at the third harmonic frequency, reducing conflicts between the two and optimizing layout efficiency without significant insertion loss or area occupation.
Implementation Method 1
a resonant frequency of the serial LC network is equal to three times of a resonance frequency of the LC tank
Implementation Method 2
a magnetic coupling between the primary 8-shape inductor and the serial LC network is mitigated due to a layout symmetry
Data Source
AI summary
An LC (inductor-capacitor) tank includes a primary 8-shape inductor and a serial LC network that are connected in parallel across a first node and a second node and laid out using a multi-layer structure fabricated on a substrate, wherein a magnetic coupling between the primary 8-shape inductor and the serial LC network is mitigated due to a layout symmetry, and a resonant frequency of the serial LC network is equal to three times of a resonance frequency of the LC tank.