MIMO Radar Frequency Transposition via Segmentation and Intermediary Signals
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Solution Overview
Problem
Airborne MIMO radars face challenges in achieving high angular resolution and long-range imaging due to significant signal losses and dispersions at high frequencies, particularly in the W band, where the distance between radar chips and antennas leads to phase and amplitude dispersions, limiting bandwidth and increasing costs.
Innovation Solution
A MIMO radar system utilizing a frequency synthesizer, frequency multiplier, and synchronized emission and reception frequency transposition components to generate and process intermediate-frequency signals, reducing signal losses by distributing the modulation bandwidth and carrier frequency across multiple paths, thereby minimizing phase errors and improving spectral purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between radar chips and antennas is increased to achieve large antenna size for fine angular resolution, then angular resolution is improved, but signal losses and phase/amplitude dispersions increase significantly at high frequencies
Solution Approach 1:
The system segments the frequency transposition function by distributing multiple synchronized frequency transposition components across different antenna channels. Each component operates independently at a lower intermediate frequency, then combines locally at the antenna, avoiding the need for long interconnections at high frequencies. This segmentation resolves the contradiction by maintaining signal integrity over longer distances through frequency division.
Solution Approach 2:
The patent introduces an intermediate frequency as a mediator between the radar chip operating frequency and the final radiating frequency. Signals are transmitted at this lower intermediate frequency through the printed circuit board to the antenna, where frequency transposition components convert them to the higher radiating frequency locally. This intermediary approach eliminates high-frequency signal losses during transmission while achieving the desired high-frequency radiation.
2Reliability
If dedicated MMIC components are used close to antennas for signal amplification, then sensitivity performance is improved, but alignment precision between emission and reception channels becomes critical and difficult to maintain
Solution Approach 1:
The frequency transposition function is segmented and distributed across multiple independent components located at different antenna positions. Each component handles its local channel independently, eliminating the need for precise alignment between separate emission and reception MMICs. This distributed segmentation maintains sensitivity performance while reducing manufacturing precision requirements.
Solution Approach 2:
The frequency transposition components serve dual functions for both emission and reception channels at each antenna location. By using universal multi-functional components rather than separate dedicated emission and reception MMICs, the system achieves high sensitivity while reducing the number of components that require precise alignment, thereby lowering manufacturing precision requirements.
3Measurement precision
If wide frequency bands are used for high distance resolution, then distance resolution is improved, but phase and amplitude dispersions increase making calibration difficult across multiple frequencies
Solution Approach 1:
The frequency band is segmented into multiple lower intermediate frequency channels, each handled by independent frequency transposition components. This segmentation allows wideband operation for high distance resolution while simplifying calibration, as each component operates at a lower frequency with reduced phase and amplitude dispersions. The modular segmented architecture makes calibration more manageable compared to a single wideband high-frequency system.
4Measurement precision
If high carrier frequencies in W band are used for airborne applications, then angular resolution and imaging capability are improved, but signal losses increase limiting range and emission power
Solution Approach 1:
The patent uses an intermediate frequency as a mediator to decouple the transmission medium requirements from the final radiation requirements. Signals are transmitted through the printed circuit board at the lower intermediate frequency where losses are minimal, then converted to high W-band frequencies locally at the antenna for radiation. This intermediary approach enables high angular resolution through high-frequency radiation while avoiding the signal losses that would occur during long-distance transmission at those high frequencies.
Solution Approach 2:
The system segments the frequency conversion process by distributing frequency transposition components across multiple antenna channels. Each component converts from intermediate frequency to high radiating frequency locally, minimizing the distance over which high-frequency signals must propagate. This segmented approach maintains the benefits of high carrier frequency for angular resolution while reducing overall signal losses.
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 system enhances the radar's ability to achieve fine angular resolution and long-range imaging while reducing signal losses and dispersions, allowing for the use of low-cost automotive radar technologies in airborne applications, with improved spectral purity and reduced impact of technological dispersion errors.
Implementation Method 1
a frequency synthesizer, configured to generate a modulated local signal, obtained by modulating a local signal having a predefined frequency over a modulation bandwidth
Implementation Method 2
at least one frequency multiplier, configured to supply an intermediate-frequency local signal to each emission channel and to each reception channel, the intermediate-frequency local signal being a fractional multiple of the modulated local signal
Implementation Method 3
each emission frequency transposition component being connected between an emission channel and an emission radiating element, and configured to mix an intermediate-frequency emission signal from an associated emission channel and the modulated local signal
Implementation Method 4
each reception frequency transposition component being connected between a reception channel and a reception radiating element, and configured to mix a signal received by an associated reception radiating element with the modulated local signal
Data Source
AI summary
The invention relates to a radar system comprising:a frequency synthesizer, configured to generate a modulated local signal (Sf0+Δf0);at least one frequency multiplier, configured to supply an intermediate-frequency local signal (Sf_inter+Δf_inter) to each emission channel (8) and to each reception channel, the intermediate-frequency local signal (Sf_inter+Δf_inter) being a fractional multiple of the modulated local signal (Sf0+Δf0);a plurality of emission frequency transposition components, the emission frequency transposition components being synchronized with one another by the modulated local wave (Sf0+Δf0);a plurality of reception frequency transposition components, the reception frequency transposition components being synchronized with one another by the modulated local signal (Sf0+Δf0), the reception channels being configured to demodulate the intermediate-frequency reception signal (Sf_inter_Rx+Δf_inter_Rx) using the intermediate-frequency local signal (Sf_inter+Δf_inter).