Transformer Secondary Coil Reuse for Harmonic Rejection Filtering
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Solution Overview
Problem
The existing matching networks in transmitters face increased loss due to harmonic rejection and coexistence/crosstalk requirements, which reduces the maximum achievable transmitter output power and increases area consumption, as well as decreases the quality factor of transformers and harmonic rejection inductors due to crowding effects.
Innovation Solution
Reusing the secondary coil of the transformer as the harmonic rejection inductor by coupling the harmonic rejection capacitor between its windings, allowing the tapped segment to function as a harmonic rejection inductor, thereby reducing area consumption and improving performance without increasing transformer crowding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a matching network is disposed in series with a power amplifier to increase maximum achievable output power, then transmitter output power is improved, but loss in the matching network increases due to harmonic rejection and coexistence/crosstalk requirements
Solution Approach 1:
The patent combines the harmonic rejection inductor with the secondary coil of the transformer by coupling the capacitor between windings of the secondary coil. This merging eliminates the need for a separate harmonic rejection inductor, reducing component count and associated losses in the matching network while maintaining both matching and harmonic rejection functions.
Solution Approach 2:
The secondary coil of the transformer is made to serve dual purposes: maintaining impedance matching and providing harmonic rejection functionality. By coupling the capacitor between windings of the secondary coil, the same component structure performs multiple functions, reducing overall network loss.
2Reliability
If separate harmonic rejection inductor is added to achieve harmonic rejection, then harmonic rejection performance is improved, but area consumption increases due to additional components
Solution Approach 1:
The patent merges the harmonic rejection inductor function with the existing secondary coil of the transformer. By coupling the capacitor between windings of the secondary coil, the same physical space serves dual purposes, eliminating the need for additional dedicated harmonic rejection components and reducing overall area consumption.
Solution Approach 2:
The secondary coil is designed to perform multiple functions simultaneously: impedance matching and harmonic rejection. This multi-functionality approach allows the system to achieve harmonic rejection performance without adding separate components that would increase area consumption.
3Area of stationary object
If multiple components are placed close together in the matching network, then area consumption is reduced, but quality factor of transformers and inductors decreases due to crowding effects
Solution Approach 1:
The patent combines the harmonic rejection functionality with the secondary coil structure, eliminating the need for a separate harmonic rejection inductor. This merging reduces the total number of components and their physical footprint, allowing components to be placed closer together without suffering from crowding effects that would degrade quality factor.
4Power
If loss in matching network is reduced to increase maximum achievable output power, then transmitter output power is improved, but harmonic rejection and coexistence/crosstalk performance may deteriorate
Solution Approach 1:
The secondary coil is designed to perform multiple functions simultaneously: impedance matching (which affects output power) and harmonic rejection. By coupling the capacitor between windings of the secondary coil, the system maintains both functions with a single integrated structure, ensuring that reducing loss to improve power output does not compromise harmonic rejection performance.
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 approach enhances the quality factor of the transformer, reduces loss in the matching network, increases transmitter output power, decreases current consumption, and provides flexibility in harmonic rejection capacitor placement, while maintaining desired radio frequency performance.
Implementation Method 1
a second inductor inductively coupled to the first inductor, the second inductor including one or more windings
Implementation Method 2
a capacitor coupled at a first terminal of the capacitor to the one or more windings and at a second terminal of the capacitor to ground
Data Source
AI summary
To reduce loss in a matching network without crowding the matching network transformer, a harmonic rejection inductor may be removed from the center of the transformer and an existing secondary coil (e.g., secondary inductor) of the transformer may be reused as the harmonic rejection inductor. The secondary coil may be reused as the harmonic rejection inductor by coupling a harmonic rejection capacitor directly to windings of the secondary coil, which may enable the portion of the secondary coil between the harmonic rejection capacitor tap point and ground to function as the harmonic rejection inductor.