Planar Array Radar Sensor Asymmetrical Beam Steering
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Solution Overview
Problem
Radar sensors for motor vehicles face challenges in detecting vehicles in the blind spot and rear area effectively, requiring a cost-effective solution that provides a wide range in the backward direction and accurate detection of vehicles at varying distances and angles.
Innovation Solution
A radar sensor system with a supply network that applies a phase shift and varying amplitude to microwave power across antenna elements, creating an asymmetrical antenna diagram to focus radiation in a specific direction while maintaining high power levels in the main lobe and reducing side lobes, allowing detection of vehicles in both lanes, including the blind spot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate antennas are used for transmitting and receiving radar signals, then the directional characteristic can be achieved, but the device complexity increases
Solution Approach 1:
The patent combines transmitting and receiving functions into a single planar array antenna structure. The same antenna elements perform both transmission and reception, eliminating the need for separate antenna systems while maintaining directional characteristics through phase-controlled signal processing.
Solution Approach 2:
The antenna elements are designed to serve multiple functions - both transmitting radar signals and receiving reflected signals. This multi-functional design reduces the overall number of components while achieving the required directional performance through electronic beamforming.
2Reliability
If microwave power is supplied to antenna elements in the same phase, then the main radiation direction is oriented at right angles to the substrate plane, but the detection range in azimuth is limited to about -45° to +45°
Solution Approach 1:
The patent introduces dynamic phase control across the antenna elements, where each element can be supplied with microwave power at different phase shifts. This dynamic phase adjustment enables the radiation pattern to be steered and extended beyond the fixed -45° to +45° azimuth range, achieving coverage up to ±90° while maintaining proper radiation directionality.
3Reliability
If a radar lens is used to achieve directional characteristic, then the beam directionality is improved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical/optical beam-forming components (radar lens) with an electronic phase-controlled array system. By adjusting the phase of microwave power supplied to each antenna element, the desired beam directionality and azimuth coverage are achieved through electronic means rather than physical optical components, reducing complexity and cost.
4Reliability
If the amplitude of emitted microwaves varies from antenna element to antenna element, then the power distribution is equalized over azimuth angle, but the main lobe intensity may be reduced
Solution Approach 1:
The patent employs amplitude tapering across the antenna elements, where the amplitude of microwave power is varied systematically from element to element. This parameter change in amplitude distribution equalizes the power distribution over the azimuth angle range, filling in position-finding gaps between main lobe and side lobes while maintaining adequate main lobe intensity through optimized tapering profiles.
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 enables efficient detection of approaching vehicles in the blind spot and rear area, ensuring timely detection of both near and distant vehicles, enhancing safety by using a single radar sensor with improved directional characteristics without the need for a radar lens.
Implementation Method 1
By interference between the radar waves radiated by the various antenna elements, there then develops an asymmetrical antenna diagram, so that a large part of the microwave power is radiated at high intensity in a certain direction
Data Source
AI summary
A radar sensor for motor vehicles has a transmitting antenna in the form of a planar array antenna having a plurality of juxtaposed antenna elements, and a supply network for supplying microwave power to the antenna elements, wherein the supply network is developed to supply the antenna elements with the microwave power having a phase shift increasing at constant increments from one end of the row to the other.