Multi-Core Double-Balanced Mixer Layout for LO Leakage Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mixers, such as diode ring and FET ring mixers, face challenges in reducing local oscillator (LO) leakage, which corrupts signal purity due to physical layout mismatches and component interferences, making it difficult to suppress LO leakage effectively across various frequency bands.
Innovation Solution
A multi-core mixer design with two double-balanced mixer cores, where each core receives a local oscillator signal 180° out of phase with the other, and input signals are also 180° out of phase, allowing the outputs to be combined to cancel LO leakage, thereby compensating for layout mismatches and improving signal purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single double-balanced mixer core is used, then the device complexity is low, but local oscillator leakage corrupts signal purity
Solution Approach 1:
The mixer is divided into two separate double-balanced mixer cores instead of using a single core. Each core processes signals independently and then their outputs are combined. This segmentation allows LO leakage from each core to be canceled when combined, improving signal purity while maintaining manageable complexity through modular design.
Solution Approach 2:
The second mixer core is configured to produce an output that is approximately 180° out of phase with the first core's output. This phase inversion creates a counterbalancing effect where LO leakage components from the two cores cancel each other out when combined, effectively reducing harmful LO leakage without requiring complex filtering.
2Object-affected harmful factors
If LO leakage reduction techniques are applied, then signal purity improves, but device complexity increases
Solution Approach 1:
Two double-balanced mixer cores are combined in parallel with their outputs summed together. This merging approach allows the beneficial cancellation of LO leakage through phase inversion while maintaining the simplicity of standard double-balanced mixer core designs. The combination achieves LO leakage reduction without requiring complex individual core modifications.
Data Source
AI summary
Systems and methods are disclosed for compensating local oscillator leakage in a mixer. An example mixer includes a first double-balanced mixer core and a second double-balanced mixer. The first double-balanced mixer may comprise differential output nodes and may be configured to mix a first input signal with a first local oscillator signal. The second double-balanced mixer core may comprise second differential output nodes and may be configured to mix a second input signal with a second local oscillator signal. The second input signal may be approximately 180° out of phase with the first input signal. The second local oscillator signal may be approximately 180° out of phase with the first local oscillator signal. The differential output nodes may be electrically connected to the second differential output nodes, and the first double-balanced mixer core and the second double-balanced mixer core may be arranged to compensate for local oscillator leakage.