Radar Receiver Asymmetric Polyphase Filtering Noise Reduction
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Solution Overview
Problem
Radar receiver noise reduction at mm wave frequencies is challenging due to semiconductor device physics limitations, and existing quadrature RF down-conversion methods are costly in terms of power consumption and hardware requirements.
Innovation Solution
A radar receiver architecture that uses a quadrature mixer circuit and an analog polyphase filter to generate complex-valued signals, filtering only one component and converting it to the digital domain, which reduces hardware and DSP effort while maintaining noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full quadrature RF down-conversion with complex signal processing is used, then receiver noise performance is improved by close-to-3 dB, but power consumption and hardware cost increase significantly
Solution Approach 1:
The patent extracts only the essential quadrature mixing function while removing the redundant complex signal processing chain. By using a quadrature mixer to generate I and Q components but then processing only one component through a single polyphase filter and ADC, the design achieves noise performance close to full quadrature processing while consuming significantly less power and using fewer hardware resources.
Solution Approach 2:
The patent applies partial action by implementing quadrature mixing (which provides the noise performance benefit) but only processing one of the two quadrature components through filtering and ADC. This partial processing approach captures the essential noise reduction benefit while avoiding the full hardware duplication required for complete complex signal processing.
2Reliability
If full quadrature RF down-conversion with complex signal processing is used, then receiver noise performance is improved by close-to-3 dB, but hardware complexity and cost increase
Solution Approach 1:
The patent extracts and retains only the critical quadrature mixing stage that provides noise performance improvement, while removing the redundant downstream processing hardware. A single polyphase filter processes one quadrature component, and a single ADC converts to digital, eliminating the need for duplicate I/Q processing chains and reducing hardware complexity significantly.
Solution Approach 2:
The patent merges the quadrature mixing function with subsequent processing by using a single polyphase filter to process one of the quadrature components. This consolidation approach maintains the noise performance benefit of quadrature mixing while reducing the number of separate processing blocks and hardware instances required.
3Reliability
If asymmetric polyphase filtering is applied to suppress noise, then receiver noise performance is improved, but filter design complexity increases
Solution Approach 1:
The patent employs asymmetric polyphase filtering where the filter transfer function is deliberately designed to be asymmetric with respect to zero frequency. This asymmetry enables the filter to provide different gain and phase characteristics for positive and negative frequency components, achieving image rejection and noise suppression while maintaining a relatively simple filter structure that can be implemented with standard polyphase filter designs.
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
Achieves similar noise performance to full quadrature radar receivers at lower power consumption and cost by suppressing noise through asymmetric filtering and channel selection.
Implementation Method 1
mixing the real-valued analog RF radar signal with a complex-valued local oscillator (LO) signal to generate a down-converted complex-valued analog signal comprising an inphase (I) signal component and a quadrature (Q) signal component
Implementation Method 2
The I- and Q-signal components of the down-converted complex-valued analog signal are filtered with an analog polyphase filter to generate filtered I- and Q-signal components
Implementation Method 3
Only one of the filtered I- and Q-signal components is converted from the analog to the digital signal domain
Data Source
AI summary
Implementations of the present disclosure relate to a radar receiver for a real-valued analog RF radar signal. The radar receiver comprises a quadrature mixer circuit configured to generate, from the real-valued analog RF radar signal, a complex-valued analog signal comprising an inphase (I) signal component and a quadrature (Q) signal component, an analog polyphase filter configured to filter the I- and Q-signal components of the complex-valued analog signal to generate filtered I- and Q-signal components, and an analog-to-digital converter coupled to an output of the analog polyphase filter. The radar receiver is configured to convert only one of the filtered I- and Q-signal components from the analog to the digital signal domain.