Waveguide-Fed Radar Antenna Stack for Low-Loss Boresight Gain
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Solution Overview
Problem
Conventional image radar systems face issues with increased size due to feeding loss and limited boresight gain, and require larger intervals between antenna patches, which affects their performance.
Innovation Solution
An image radar apparatus with a vertical feeding structure using waveguides, where the radar chip and antenna patches are mounted on separate PCBs with a feeding waveguide connecting them, reducing feeding loss and antenna patch intervals, and enhancing boresight gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional PCB layout with feeding lines is used, then the radar chip and antenna patches can be connected, but the feeding loss increases due to longer feeding lines and the area of the PCB needs to be increased
Solution Approach 1:
The patent transitions from a planar PCB layout to a three-dimensional stacked architecture where the radar chip is mounted on a first PCB and antenna patches are mounted on a second PCB positioned above it. This vertical arrangement in another dimension (height direction) significantly shortens the feeding line length, reducing feeding loss without increasing the horizontal PCB area.
Solution Approach 2:
The patent implements a nested structure where the second PCB with antenna patches is positioned above and integrated with the first PCB containing the radar chip. The feeding waveguide is embedded within the stacked configuration, creating a compact nested arrangement that reduces overall system footprint while minimizing feeding path length.
2Volume of stationary object
If waveguide slot array antennas are used to reduce radar apparatus size, then vertical stacking is achieved, but the beam width becomes 100 degrees or more in narrow slot direction, lowering boresight gain
Solution Approach 1:
The patent employs different waveguide structures for different functional requirements: E-plane bent waveguides are used in specific positions to control beam width and enhance boresight gain, while maintaining the compact vertical stacking for size reduction. This localized optimization of waveguide geometry achieves both small size and high boresight gain.
Solution Approach 2:
The patent modifies waveguide parameters including bending the E-plane waveguides at specific angles and adjusting waveguide dimensions to control beam width. By changing these geometric parameters, the system achieves narrow beam width (less than 100 degrees) while maintaining the compact vertical stacked configuration for reduced radar apparatus size.
3Volume of stationary object
If waveguide slot array antennas are used, then vertical stacking is achieved, but grating lobes occur because the interval between antennas must be greater than 0.6 wavelengths
Solution Approach 1:
The patent uses bent E-plane waveguides that dynamically adjust the phase distribution across the antenna array. The bending angles and positions of waveguides are optimized to control the effective electrical spacing between antenna elements, preventing grating lobes even when physical spacing is reduced for compact size.
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 solution results in a compact image radar system with improved boresight gain and reduced size, while minimizing feeding loss and antenna patch intervals, thereby enhancing overall radar performance.
Implementation Method 1
a feeding waveguide disposed between the main PCB and the sub-PCB and configured to feed the radar chip mounted on the main PCB, and the at least one transmitting antenna patch and the at least one receiving antenna patch mounted on the sub-PCB
Data Source
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AI summary
The present disclosure relates to an image radar apparatus with a vertical feeding structure using a waveguide, which can reduce the size of a radar apparatus while reducing a feeding loss, have excellent boresight gain, and reduce an interval between antenna patches due to the vertical feeding structure using waveguides.