Weakly Coupled Harmonic Rejection Filter for Power Amplifier Linearization
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Solution Overview
Problem
RF amplification devices face challenges in achieving compact designs while maintaining weak mutual magnetic coupling, which is essential for reducing harmonic rejection and bandwidth tradeoffs, and in mitigating broadband noise that degrades signal-to-noise ratios in closed-loop control circuits.
Innovation Solution
The implementation of an RF filter with a first inductor coil and a second inductor coil, where the second winding of the second inductor coil is configured to have a first mutual magnetic coupling with the first winding of the first inductor coil, and a third winding is connected to the second winding such that the mutual magnetic couplings are in opposition, allowing for a compact arrangement with weak mutual magnetic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional weakly magnetically coupled inductor coils are used to achieve weak mutual magnetic coupling, then harmonic rejection and quality factor are improved, but the area occupied by the inductor coils increases significantly
Solution Approach 1:
The second inductor coil is segmented into multiple windings (second winding and third winding) that are connected in series. This segmentation allows the windings to be positioned closer to the first inductor coil while maintaining weak mutual coupling through the series connection, thereby reducing the overall area occupied by the inductor structure.
Solution Approach 2:
The patent transitions from a single-coil configuration to a multi-winding configuration where the second inductor coil has both a second winding and a third winding. This dimensional change in the coil structure enables weak mutual coupling to be achieved with smaller spacing between coils, reducing the area requirement.
2Area of stationary object
If inductor coils are placed close together to reduce area, then device compactness is improved, but mutual magnetic coupling increases causing harmonic distortion
Solution Approach 1:
By segmenting the second inductor coil into multiple windings connected in series, the patent achieves weak mutual coupling even when coils are placed close together. The series connection of the second and third windings creates a configuration where the mutual coupling effects are reduced, allowing compact placement without excessive coupling.
Solution Approach 2:
The patent changes the structural parameters of the inductor coils by introducing multiple windings with specific connection configurations. This parameter change allows the mutual coupling coefficient to be controlled and reduced, enabling compact coil placement while maintaining weak coupling.
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 enables efficient harmonic rejection and reduced noise interference, enhancing the signal-to-noise ratio and allowing for more compact RF filter designs without the need for large distances between inductor coils.
Implementation Method 1
the second winding of the second inductor coil is configured to have a first mutual magnetic coupling with the first winding of the first inductor coil, and a third winding is connected to the second winding such that the mutual magnetic couplings are in opposition
Data Source
AI summary
Radio frequency (RF) filters configured to filter undesired signal components (e.g., noise and harmonics) from RF signals are disclosed. In one embodiment, an RF filter includes a first inductor coil having a first winding and a second inductor coil having a second winding and a third winding. The second winding of the second inductor coil is configured to have a first mutual magnetic coupling with the first winding, while the third winding of the second inductor coil is configured to have a second mutual magnetic coupling with the first winding. The second winding is connected to the third winding such that the first mutual magnetic coupling and the second mutual magnetic coupling are in opposition. In this manner, the first inductor coil and the second inductor coil may be provided in a compact arrangement while providing weak mutual magnetic coupling between the first inductor coil and the second inductor coil.