On-Chip Lange Coupler Cross-Coupling Amplitude Balance
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Solution Overview
Problem
Conventional on-chip Lange couplers suffer from insufficient coupling and amplitude unbalance due to larger size and design constraints, leading to increased costs and reduced frequency bandwidth.
Innovation Solution
The design features a Lange coupler with lines arranged in a cross-coupling structure across two levels, where thicker upper-level lines are used to enhance electromagnetic coupling both vertically and horizontally, improving coupling efficiency and amplitude balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional on-chip Lange couplers use higher level metal layers for signal traces to reduce resistance loss, then resistance loss is reduced, but coupling among lines becomes insufficient and amplitude unbalance occurs
Solution Approach 1:
The patent transitions from planar coupling to three-dimensional cross-level coupling by positioning signal traces on different metal layers. Specifically, first signal traces are placed on a first metal layer while second signal traces are placed on a second metal layer, enabling vertical electromagnetic coupling in addition to horizontal coupling. This dimensional change allows sufficient coupling strength without requiring excessively close spacing that would cause manufacturing precision issues.
Solution Approach 2:
The patent introduces dielectric layers as intermediaries between the signal traces on different metal layers. These dielectric layers provide controlled impedance matching and facilitate electromagnetic coupling between the traces while maintaining proper spacing. The dielectric structure acts as a mediator that enables effective energy transfer between layers without direct contact, resolving the coupling insufficiency problem.
2Manufacturing precision
If branchline couplers are used for on-chip implementation to achieve better amplitude balance, then amplitude balance is improved, but device size increases and cost increases
Solution Approach 1:
The patent achieves compact coupling by utilizing vertical space through multiple metal layers. Instead of expanding the device footprint horizontally as branchline couplers require, the invention stacks signal traces vertically on different layers, enabling strong coupling within a small planar area. This three-dimensional arrangement provides branchline-coupler-quality amplitude balance without the associated size increase.
3Area of stationary object
If conventional Lange couplers are used for on-chip implementation, then device size is reduced and cost is reduced, but coupling among lines becomes insufficient and amplitude unbalance occurs
Solution Approach 1:
The patent maintains the compact footprint of conventional Lange couplers by implementing them in a three-dimensional multi-layer configuration. Signal traces are distributed across multiple metal layers with vertical coupling enabled through the dielectric structure, achieving sufficient coupling strength and proper amplitude balance without increasing the device's planar dimensions.
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 results in better amplitude balance and reduced insertion loss while maintaining similar performance in phase balance and physical size, compared to traditional on-chip Lange couplers, and is more cost-effective than branchline couplers.
Implementation Method 1
At least one line on the first level is cross-coupled to a respective line on the second level
Data Source
AI summary
A Lange coupler having a first plurality of lines on a first level and a second plurality of lines on a second level. At least one line on the first level is cross-coupled to a respective line on the second level via electromagnetic waves traveling through the first and second plurality of lines. The first and second plurality of lines may be made of metal, and the first level may be higher than the second level. A substrate may be provided into which the first and second plurality of lines are etched so as to define an on-chip Lange coupler.