Magnetically Cross-Coupled Wilkinson Circuit for Compact RF Design
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Solution Overview
Problem
Traditional lumped Wilkinson combiners require large inductive elements for proper operation, leading to increased size and resistive losses, which is a challenge in compact and efficient RF communications circuits.
Innovation Solution
A lumped cross-coupled Wilkinson circuit with magnetically cross-coupled inductive elements, reducing the inductance and size of each inductive element while minimizing resistive losses, and allowing the circuit to operate as both a combiner and a splitter with an impedance matching network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lumped Wilkinson combiner uses large inductive elements for proper operation, then impedance matching and isolation are achieved, but the size and resistive losses increase
Solution Approach 1:
The patent transforms the traditional series inductive elements into magnetically coupled inductive elements with mutual inductance. By changing the circuit topology from series to magnetically coupled configuration, the inductance values can be significantly reduced while maintaining the same impedance matching and isolation performance. The magnetic coupling creates a new operational mode that achieves the same electrical function with different physical parameters.
Solution Approach 2:
The patent combines two separate inductive paths into a magnetically coupled system where the inductive elements share a common magnetic flux. This merging of magnetic fields through mutual inductance allows the circuit to achieve the same isolation and matching functions with reduced individual inductance values, thereby reducing resistive losses and overall size.
2Reliability
If traditional lumped Wilkinson combiner uses large inductive elements, then proper operation is achieved, but the overall circuit size increases
Solution Approach 1:
By changing from series inductors to magnetically coupled inductors, the patent reduces the physical dimensions required. The mutual inductance allows smaller inductive elements to provide the same electrical function, directly reducing the area occupied by the inductive components in the circuit layout.
Solution Approach 2:
The magnetic coupling introduces a spatial relationship between the inductive elements that exploits magnetic field interaction in three-dimensional space. This allows the circuit to achieve its function with more compact planar arrangements, effectively reducing the footprint area by utilizing vertical magnetic flux coupling rather than requiring large planar inductor areas.
3Reliability
If traditional lumped Wilkinson combiner uses large inductive elements, then proper operation is achieved, but resistive losses increase
Solution Approach 1:
The transformation to magnetically coupled inductive elements changes the current distribution and magnetic flux patterns, allowing the same isolation function to be achieved with lower inductance values. Since resistive losses are proportional to the square of the current times the resistance, and smaller inductors typically have lower series resistance, the overall resistive losses are reduced.
Solution Approach 2:
By merging the magnetic fields of the two inductive elements through mutual coupling, the patent creates a more efficient current path that reduces circulating currents and associated resistive losses. The magnetic coupling allows the system to achieve isolation through flux cancellation rather than requiring large inductors that would generate higher ohmic losses.
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 solution results in significantly smaller and more efficient inductive elements, reducing the overall size and resistive losses, while maintaining impedance matching and isolation, suitable for compact RF communications devices.
Implementation Method 1
The second inductive element L2 is magnetically cross-coupled to the first inductive element L1, and the first inductive element L1 has a first inductance and the second inductive element L2 has a second inductance, both of which may be less than comparable inductances in a traditional lumped Wilkinson combiner
Data Source
AI summary
The present invention relates to a lumped cross-coupled Wilkinson circuit having a pair of magnetically cross-coupled inductive elements coupled to an isolation network. By magnetically cross-coupling the inductive elements, which have a mutual inductance, the inductance of each inductive element will be significantly less than the inductance of each inductive element in an equivalent lumped traditional Wilkinson combiner. Since the inductance of each inductive element is less, the size of each inductive element may be significantly smaller and the resistive loss of the each inductive element may be significantly smaller. In one embodiment of the present invention, the lumped cross-coupled Wilkinson circuit operates as a lumped cross-coupled Wilkinson combiner. In an alternate embodiment of the present invention, the lumped cross-coupled Wilkinson circuit operates as a lumped cross-coupled Wilkinson splitter.