PCB Radar Array Beamforming for Wide-Angle Low-Sidelobe Coverage
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Solution Overview
Problem
Radar systems face challenges in achieving wide fields of view with reduced side lobes and increased gain and phase linearity, particularly in super-hemispherical coverage, due to limitations in phase control and beam forming techniques.
Innovation Solution
The system employs an antenna array with a wave deflection mechanism, such as a reflector, and binary phase shifters to apply controlled phase shifts, simulating quadrature phase-shift key (QPSK) beam forming, and utilizes a MIMO array configuration with antennas on multiple facets of a Printed Circuit Board (PCB) to achieve wide fields of view and super-hemispherical coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If arbitrary phase shift is applied to antenna elements to achieve highly directional beams, then beam directionality is improved, but implementation complexity increases and coarse phase control generates significant side lobes
Solution Approach 1:
The patent changes the phase control parameter from arbitrary continuous phase shifts to discrete quantized phase values (0, 90, 180, 270 degrees). This parameter quantization reduces implementation complexity while maintaining beam directionality through the relationship: phase_shift[k] = quantize(phase_desired[k], 90 degrees), where the quantized phases are applied to antenna elements to form directed beams with reduced side lobes.
Solution Approach 2:
The patent applies different quantized phase shifts to different antenna elements based on their specific positions and required beam directions. Each antenna element k receives a locally optimized phase shift phase_shift[k] calculated from the desired beam direction and element position, ensuring that each element contributes optimally to the overall beam pattern with reduced side lobes.
2Device complexity
If BPSK beam forming with coarse phase control is used, then implementation complexity is reduced, but about 60% of transmission energy is lost to side lobes
Solution Approach 1:
The patent refines the phase control parameter from 180-degree granularity (BPSK) to 90-degree granularity (QPSK). This parameter refinement allows for more precise beam shaping, reducing side lobe levels and improving energy concentration in the main beam direction. The relationship energy_concentration = 1 - side_lobe_level shows that reduced side lobes directly improve energy utilization.
Solution Approach 2:
The patent converts the inherent limitation of discrete phase control (which typically generates side lobes) into a benefit by carefully selecting quantized phase values that minimize side lobe levels. Through optimized phase quantization strategies, the discrete phase shifts that would normally create harmful side lobes are instead configured to produce constructive interference in the main beam direction while minimizing energy in side lobes, achieving over 80% energy concentration.
3Adaptability or versatility
If transmission sweep over a range of frequencies is transmitted over time intervals, then frequency coverage is improved, but delay between time intervals increases and phase rotation from moving targets deteriorates imaging accuracy
Solution Approach 1:
The patent applies preliminary phase compensation to correct for expected phase rotation caused by target motion during the frequency sweep. By calculating and applying compensatory phase shifts before transmission, the system pre-corrects for the phase rotation that will occur during the extended transmission time, maintaining imaging accuracy despite the longer observation interval required for frequency sweeping.
Solution Approach 2:
The patent implements feedback mechanisms to measure and correct phase rotation effects in real-time. By monitoring the phase changes introduced by target motion during frequency sweeping and applying corrective transformations to the received signals, the system maintains accurate target location and imaging quality despite the extended time intervals inherent in frequency sweep operations.
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 significantly reduces side lobes, enhances gain and phase linearity, and provides effective beam forming, enabling accurate target location and improved radar coverage in a cost-effective manner.
Implementation Method 1
a wave deflection mechanism mounted in proximity to the printed circuit board. The wave deflection mechanism may be configured such that waves transmitted away from the board by the array of transmitting antennas are incident upon the wave deflection mechanism and are directed away from the board with a different direction and field of view
Implementation Method 2
The system employs an antenna array with a wave deflection mechanism, such as a reflector, and binary phase shifters to apply controlled phase shifts, simulating quadrature phase-shift key (QPSK) beam forming
Implementation Method 3
The application of radar is becoming more and more popular with the development of the signal technology progress. Radar is an electronic system with the advantages of low cost, low-power consumption, and high precision
Data Source
AI summary
A printed circuit board mounted radar system for monitoring a target region, including an array of transmitting antennas mounted to a printed circuit board, an array of receiving antennas mounted to the printed circuit board, a wave deflection mechanism mounted to the printed circuit board configured such that waves transmitted perpendicularly to the board by the array of transmitting antennas are incident upon the wave deflection mechanism and are directed radially away from the board, and waves reflected from objects within the target region radially towards the wave deflection mechanism are directed towards the receiving antennas in a direction perpendicular to the board.