Radar Transmit Bandwidth Augmentation With LO Leakage Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional radar systems are limited by the bandwidth of digital-to-analog converters (DACs), which restrict the resolution of emitted radar signals, making high-resolution DACs costly and unsuitable for commercial use.
Innovation Solution
Employ multiple lower sampling rate DACs in combination with distortion systems, feedforward loops, and LO selection to generate a very high instantaneous bandwidth (IBW) radar signal with constant amplitude and phase across frequencies, using inexpensive commercial-off-the-shelf components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution DAC with very high sampling rate is used, then the instantaneous bandwidth and resolution of the radar signal are improved, but the cost of the system increases significantly
Solution Approach 1:
The patent divides the high-bandwidth signal generation task into multiple segments by using several lower sampling rate DACs, each handling a portion of the total bandwidth. This segmentation allows the system to achieve the same high-resolution performance as a single high-end DAC would provide, but using multiple more affordable, lower-performance components that are commercially available.
2Measurement precision
If multiple RF signals from different transmit channels are combined, then the instantaneous bandwidth is increased, but local oscillator leakage causes amplitude spikes and non-constant phase across frequencies
Solution Approach 1:
The patent applies preliminary anti-action by pre-distorting the digital IF signals to compensate for the expected local oscillator leakage effects before the signals are combined. This pre-compensation ensures that when the RF signals are combined at the output, the leakage-induced amplitude spikes and phase variations are already corrected, resulting in a combined signal with relatively constant amplitude and phase characteristics across the extended frequency band.
3Measurement precision
If frequency bands of two transmit channels partially overlap, then the combined instantaneous bandwidth is enhanced, but amplitude variance occurs in the overlapping region
Solution Approach 1:
The patent implements preliminary action by computing and applying correction signals that pre-adjust the amplitude and phase of digital IF signals before they are converted to RF and combined. This advance correction ensures that when frequency bands overlap during combination, the resulting amplitude variance is compensated for, maintaining consistent signal composition across the entire combined bandwidth including overlapping regions.
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 radar system generates high-resolution data with a very high IBW, overcoming the limitations of conventional systems by minimizing LO leakage and ensuring consistent signal quality.
Implementation Method 1
The mixer receives the IF analog signal and mixes the IF analog signal with a local oscillator (LO), thereby upconverting the IF analog signal to a radio frequency (RF) analog signal
Data Source
AI summary
Various technologies pertaining to forming a very high instantaneous bandwidth (IBW) radar signal based upon several radio frequency (RF) signals that have sub-bands of the frequency band of the radar signal are described herein. A radar system is configured to address local oscillator leakage across multiple transmit channels of the radar system, such that the radar signal has a relatively constant or other desired amplitude and phase across frequencies of the radar signal. In addition, the radar system is configured to compute a correction signal that pre-distorts each of the sub-frequency channels such that upon combining enables the generation of desired amplitude and phase response across a transmitted pulse.