Symmetrical Resistive HRM Circuit for Harmonic Rejection
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Solution Overview
Problem
Interference between different signals in RF circuits of wireless communication devices, particularly in carrier aggregation configurations, leads to reduced signal quality due to leakage paths and harmonic interference, which existing technologies have not adequately addressed.
Innovation Solution
Implementing a symmetric configuration of I- and Q-channel paths with shared capacitors and configurable resistors in RF mixers to achieve harmonic rejection, providing gain scaling independent of input impedance and reducing dependency on separate capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional mixer configurations are used in carrier aggregation, then device complexity is reduced, but harmonic rejection ratio deteriorates due to interference between different frequency bands
Solution Approach 1:
The mixer is divided into separate I-channel and Q-channel paths, each with dedicated mixers and local oscillator inputs. This segmentation allows independent optimization of each path to achieve harmonic rejection while maintaining overall system functionality.
Solution Approach 2:
The patent employs asymmetric mixer configurations where the I-channel and Q-channel paths have different mixer arrangements and local oscillator phase relationships. This asymmetry enables differential cancellation of harmonic interference components while preserving the desired signal.
2Manufacturing precision
If separate capacitors are used for I- and Q-channel paths, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
A single capacitor is shared between the I-channel and Q-channel mixer inputs. This merging of components reduces the total component count and simplifies the circuit while maintaining the ability to achieve accurate gain scaling through the symmetric resistor configuration.
Solution Approach 2:
The shared capacitor serves both I-channel and Q-channel mixer inputs simultaneously, providing multi-functionality. This universal component approach reduces complexity while the path-specific resistors maintain the precision needed for gain control in each channel.
3Manufacturing precision
If symmetrical load configuration is applied to local oscillator signals, then harmonic rejection ratio is improved, but power consumption increases
Solution Approach 1:
The local oscillator signals are applied in periodic phases to the I- and Q-channel mixers, with specific phase relationships that enable harmonic rejection. This periodic switching approach achieves the symmetrical load effect while controlling power consumption through duty-cycled operation.
Data Source
AI summary
This disclosure provides systems, methods, and devices for wireless communications that support downconversion of signals with improved harmonic rejection. In a first aspect, an apparatus includes a first plurality of mixers with each mixer coupled to two oscillating signals that are 180 degrees apart in phase; a second plurality of mixers with each mixer coupled to two oscillating signals that are 180 degrees apart in phase, wherein a combined load of the first plurality of mixers and the second plurality of mixers on the plurality of oscillating signals is symmetric as to each oscillating signal of the plurality of oscillating signals; and a shared capacitor coupling the RF input to the first plurality of mixers and the second plurality of mixers. Other aspects and features are also claimed and described.