Regenerative Receiver Architecture for Millimeter-Wave Imaging
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Solution Overview
Problem
Existing millimeter and sub-millimeter wave imaging systems face challenges in achieving high-resolution, cost-effective, and power-efficient operation due to high power consumption, large circuit area requirements, and complex signal routing in pixel arrays, particularly in implementing large-scale imaging arrays.
Innovation Solution
A digital regenerative receiver (DRR) architecture that uses a regenerative oscillator quenched by a digital circuit, eliminating the need for analog-to-digital conversion and reducing power consumption and circuit area, along with a multi-band inter-modulated regenerative receiver (IRR) and antenna-less super regenerative receiver (ASRR) designs for efficient operation and compact pixel size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional multiple-stage or heterodyne-based imaging receivers are used, then signal reception capability is improved, but power dissipation increases due to large number of bias currents
Solution Approach 1:
The patent extracts and eliminates unnecessary bias current stages from traditional multiple-stage or heterodyne-based receivers. By using a single-stage regenerative receiver architecture, it removes redundant amplification stages and associated bias currents, thereby reducing power dissipation while maintaining signal reception capability through the regenerative oscillation mechanism.
Solution Approach 2:
The patent changes the operating parameters by transitioning from traditional heterodyne frequency conversion to direct regenerative detection. This parameter change allows the receiver to operate with minimal bias currents while achieving high gain through positive feedback in the regenerative oscillator, thus resolving the contradiction between reception capability and power consumption.
2Reliability
If traditional multiple-stage or heterodyne-based imaging receivers are used, then signal reception capability is improved, but silicon area increases due to large number of passive devices
Solution Approach 1:
The patent extracts and removes unnecessary passive devices such as multiple filters, mixers, and intermediate frequency components from traditional heterodyne receivers. The single-stage regenerative architecture requires minimal passive components, dramatically reducing the silicon area occupied by each pixel while preserving signal reception through the regenerative detection principle.
Solution Approach 2:
The patent merges multiple functional stages (amplification, frequency selection, and detection) into a single regenerative receiver stage. This consolidation eliminates the need for separate passive devices in each stage, reducing overall silicon area while maintaining comprehensive signal reception capability through the integrated regenerative oscillation and detection process.
3Measurement precision
If high-resolution systems with large number of pixels are implemented, then imaging resolution is improved, but total power consumption increases due to n2 scaling in square arrays
Solution Approach 1:
The patent segments the receiver functionality into independent, identical pixel units, each implementing a compact single-stage regenerative receiver. This segmentation allows for scalable array construction where each pixel operates autonomously with minimal power consumption, preventing the n2 scaling problem by ensuring each segment consumes constant power regardless of array size.
Solution Approach 2:
The patent changes the power consumption parameter at the pixel level by implementing ultra-low-power regenerative circuitry. By optimizing the regenerative oscillator parameters and using minimal bias currents, each pixel consumes significantly less power than traditional receivers, allowing high-resolution arrays to be constructed without prohibitive total power consumption.
4Measurement precision
If high-resolution systems with large number of pixels are implemented, then imaging resolution is improved, but device area increases making wafer integration difficult
Solution Approach 1:
The patent segments the imaging system into identical, modular pixel units that can be systematically arranged on a wafer. Each pixel implements a compact single-stage regenerative receiver with minimal passive devices, enabling high-density integration. This segmentation strategy allows large arrays to fit on standard wafers by optimizing the footprint of each segment and using regular patterning techniques.
Solution Approach 2:
The patent merges multiple functions (RF reception, amplification, frequency selection, and detection) into a single integrated circuit block per pixel. This functional integration eliminates the need for separate discrete components and interconnect structures, dramatically reducing the device area required per pixel and enabling wafer-level integration of high-resolution arrays.
5Reliability
If large numbers of analog signals are routed between pixels and sampling ADC, then signal transmission is achieved, but routing complexity increases
Solution Approach 1:
The patent extracts and removes the analog-to-digital conversion stage from each pixel, eliminating the need for complex analog signal routing to external ADCs. By implementing digital processing directly in each pixel or using digital signal representation, it simplifies the interconnect architecture and reduces routing complexity while maintaining reliable signal transmission.
Solution Approach 2:
The patent substitutes analog signal transmission with digital signal representation or processing. By converting the output of the regenerative receiver to a digital format or using digital logic levels for signal transmission, it replaces the complex analog routing infrastructure with simpler digital interconnects that are easier to manage and less susceptible to interference.
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 DRR achieves low power dissipation and small pixel area, simplifying signal routing and enabling high-resolution imaging, while the IRR and ASRR enhance frequency operation and reduce noise, respectively, leading to more efficient and compact millimeter and sub-millimeter wave imaging systems.
Implementation Method 1
a regenerative oscillator configured for oscillating at a first frequency in response to receiving a signal
Implementation Method 2
an envelope detector coupled to an output of the regenerative oscillator, the envelope detector configured for generating a digital envelope threshold output in response to detecting that an oscillation envelope has reached a threshold
Data Source
AI summary
A millimeter and sub-millimeter wavelength receiver imaging apparatus and method which directly generates a time encoded digital signal for an imaging pixel in response to interoperation of a digital quench circuit, an envelope detector, and a regenerative oscillator coupled to an antenna. The device utilizes the fact that oscillator startup time in a regenerative oscillator is inversely proportional to injected pixel image power. A digital quench circuit, such as a latch, is coupled for activating and deactivating the regenerative oscillator in response to receiving an output from an envelope threshold circuit, and for generating a time encoded digital signal in response to pixel amplitude during millimeter and sub-millimeter wavelength imaging. Receiver embodiments are described for both fundamental frequency operation (DRR) and for multi-frequency imaging (IRR).