Radar Frequency Multiplier Signal Isolation
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Solution Overview
Problem
In-vehicle radar apparatuses face challenges in achieving high-frequency signal isolation, leading to noise interference and malfunction due to signal leakage between transmitter and receiver, especially at high frequencies like microwave and millimeter wavebands, which affects accurate object detection and increases power consumption.
Innovation Solution
The radar apparatus employs a frequency multiplier with differential circuits and bias terminals to secure high-frequency signal isolation, suppress signal leakage, and reduce power consumption by setting the oscillator output level lower than conventional methods, using pseudo-noise codes and differential amplifiers to manage signal transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the oscillator output level is increased to improve signal transmission, then the transmission signal strength is improved, but signal leakage from transmitter to receiver increases causing noise interference
Solution Approach 1:
A frequency multiplier is introduced as an intermediary component between the oscillator and the transmitter. The frequency multiplier converts the oscillator signal at a lower frequency to a higher frequency, which then modulates the transmission signal. This intermediary structure allows the oscillator to operate at a lower output level while still achieving sufficient transmission signal strength through frequency multiplication and modulation, thereby reducing signal leakage noise.
Solution Approach 2:
The patent changes the frequency parameter of the oscillator signal by using a frequency multiplier to convert it to a higher frequency before transmission. This parameter change allows the system to achieve the required transmission signal strength through frequency multiplication rather than increasing the oscillator output power directly, thus reducing signal leakage and noise interference in the receiver.
2Measurement precision
If high-frequency signals are used to improve detection accuracy, then the detection precision is improved, but signal isolation between transmitter and receiver becomes difficult causing malfunction
Solution Approach 1:
The frequency multiplier serves as an intermediary that enables the use of high-frequency signals for improved detection accuracy while preventing direct high-frequency signal leakage. By converting the oscillator signal through frequency multiplication in a controlled manner, the system achieves high-frequency operation benefits without the direct coupling and isolation problems that would occur if the oscillator itself operated at high frequency.
Solution Approach 2:
The signal generation process is segmented into distinct stages: oscillator at lower frequency, frequency multiplication stage, modulation stage, and transmission stage. This segmentation allows each stage to be optimized independently, with the oscillator operating at a frequency that minimizes leakage while the frequency multiplier and modulator stages achieve the required high-frequency transmission for accurate detection.
3Use of energy by stationary object
If the oscillator output level is reduced to decrease power consumption, then the power consumption is reduced, but the transmission signal strength becomes insufficient
Solution Approach 1:
The frequency parameter is changed through multiplication by the frequency multiplier circuit. The oscillator operates at a lower frequency with reduced power consumption, and the frequency multiplier increases the frequency by a specific ratio (e.g., 2x, 3x, or higher). This parameter transformation allows the transmission signal to achieve sufficient strength through frequency multiplication rather than requiring high oscillator power output.
Solution Approach 2:
The frequency multiplier acts as an intermediary that bridges the gap between low-power oscillator output and sufficient transmission signal strength. It converts the low-power, low-frequency oscillator signal into a higher-frequency signal that, after modulation, achieves the required transmission strength without requiring the oscillator itself to consume high power.
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 solution effectively secures high-frequency signal isolation, prevents signal leakage, and reduces power consumption, maintaining a high Signal-to-Noise ratio for accurate object detection while meeting detection probability and error alarm requirements.
Implementation Method 1
a transmission multiplier, made up of a differential circuit for inputting and outputting a differential signal, to which a high-frequency signal divided for transmission from the high-frequency signal generated by the oscillator is inputted as a transmission differential signal which is the differential signal, and which multiplies a frequency of the transmission differential signal by a predetermined multiplication ratio
Implementation Method 2
made up of a differential circuit for inputting and outputting a differential signal
Implementation Method 3
The radar wave transmitted from the transmitting antenna 17 is reflected by the obstacle. The reflected wave which is obtained by being reflected by the obstacle is received as a reception signal by a receiving antenna 18.
Data Source
AI summary
A radar apparatus includes a PN code generator for generating a PN code, a variable delay device for delaying the PN code, an oscillator for generating a high-frequency signal, a transmission frequency multiplier for multiplying a frequency of a transmission differential signal obtained by being divided from the high-frequency signal by 3, a reception frequency multiplier for multiplying a frequency of a reception differential signal obtained by being divided from the high-frequency by 3, a transmitter for generating a radar wave by using the differential signal obtained through the multiplication by the transmission frequency multiplier and the PN code generated by the PN code generator, and a receiver for generating an in-phase signal and a quadrature signal from a reflected wave by using the differential signal obtained through the multiplication by the reception frequency multiplier and the PN code delayed by the delay device.