FMCW Radar Elevation Scanning With Synchronized Receive Aperture
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Solution Overview
Problem
Existing FMCW radars face challenges in efficiently scanning a radio frequency antenna beam along multiple axes, particularly in adjusting the transmit beam in elevation while synchronizing the receive aperture to maintain effective signal reception.
Innovation Solution
The disclosure describes techniques for scanning a radio frequency antenna beam by synchronizing the receiver circuitry with the transmitter circuitry to scan both the transmit beam and the receive aperture in elevation, using varactor phase shifters and multi-channel control devices to adjust phase and amplitude, allowing for efficient scanning and signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the transmit beam is fixed with wide azimuth coverage, then the azimuth field of view is improved, but the elevation scanning capability deteriorates
Solution Approach 1:
The patent applies dynamics by making the transmit beam steerable in elevation through phased array technology. The fixed wide azimuth beam is transformed into a dynamic beam that can be electronically steered to different elevation angles, allowing the radar to adapt its coverage area while maintaining wide azimuth illumination. This resolves the contradiction by enabling elevation scanning capability without sacrificing azimuth field of view.
Solution Approach 2:
The patent changes the beam direction parameter in the elevation plane while maintaining the wide azimuth coverage. By adjusting the phase shifters in the vertical array elements, the beam can be steered to different elevation angles, transforming the fixed beam pattern into a configurable one that adapts to different scanning requirements while preserving the original azimuth coverage characteristics.
2Adaptability or versatility
If electronic scanning is performed in receiver only, then the receiver versatility is improved, but the transmit-receive synchronization deteriorates
Solution Approach 1:
The patent applies universality by implementing phased array beam steering on both transmit and receive sides. This multi-functional approach allows the same electronic scanning mechanism to be used for both transmission and reception, ensuring that the transmit and receive beams are synchronized in elevation while maintaining the versatility of electronic scanning. The system achieves both receiver versatility and transmit-receive synchronization through unified beam control.
3Measurement precision
If the transmit beam is narrowed in elevation, then the elevation resolution is improved, but the coverage area deteriorates
Solution Approach 1:
The patent applies dynamics by using electronic beam steering to dynamically adjust the elevation coverage area during scanning operations. While the beam width in elevation remains narrow for high resolution, the electronic steering capability allows the beam to be swept across different elevation angles, effectively increasing the total coverage area. This resolves the contradiction by maintaining narrow beam width for resolution while achieving wide coverage through dynamic scanning.
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
This approach enables efficient scanning of the transmit beam in elevation and synchronization of the receive aperture, enhancing the radar system's ability to receive reflected signals over a larger field of view compared to fixed transmit beams.
Implementation Method 1
a first varactor that connects the 90-degree output terminal to ground; and a second varactor that connects the isolated terminal to ground
Implementation Method 2
the phase shifter comprises: a phase shifter output terminal connected to the second input terminal of the second power divider; a 90-degree hybrid coupler with: a phase shifter input terminal connected to the second output terminal of the first power divider
Implementation Method 3
a 90-degree hybrid coupler with: a phase shifter input terminal connected to the second output terminal of the first power divider; a 90-degree output terminal; an isolated terminal
Implementation Method 4
frequency modulated continuous wave (FMCW) transmit antenna array device
Implementation Method 5
The disclosure relates to compact frequency modulated continuous wave (FMCW) radars
Data Source
AI summary
The disclosure describes techniques to scan a radio frequency antenna beam along one or more axes. For example, for a wide transmit beam oriented such that the long axis is in azimuth, this disclosure describes techniques to scan the transmit beam in elevation, in the direction of a short axis of the transmit beam. The radar receive aperture may be synchronized with transmit beam to scan the radar receive aperture using RF beamforming such that the elevation scan of the field of view of the radar receive aperture follows the elevation scan of the transmit beam. The radar receiver circuitry may also down-convert the received radar signals to an intermediate frequency (IF). The radar receiver circuitry may digitally form monopulse receive beams at IF within the processing circuitry of the receiver electronics and digitally scan the monopulse receive beams along the long axis of the field of view.