Optical Modulator Radio Oscillator for Millimeter-Wave Radar
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Solution Overview
Problem
The high cost and complexity of millimeter-wave radar systems, particularly due to the high cost of RF parts and the need for multiple radar systems in Intelligent Transport Systems, along with the requirement for high reliability and stability in oscillators, make it challenging to achieve efficient and cost-effective radar systems for vehicle safety applications.
Innovation Solution
A radio oscillating system utilizing an optical modulator with a specific modulating signal frequency and optical receiver configuration, which generates radio signals efficiently by interposing sideband waves and using a high-pass filter to minimize unnecessary signals, reducing the need for high-performance and high-reliability amplifiers and filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a mode locking laser system is used to generate multiple radio signals, then the number of oscillators can be reduced, but many unnecessary radio signals are generated requiring severe specification filters
Solution Approach 1:
The patent extracts only the necessary radio signal frequency component from the multiple signals generated by the mode locking laser. By using a frequency filter to select specifically the desired beat frequency signal and eliminate other unnecessary signals, the system achieves signal purification without requiring severe specification filters across the entire frequency range.
Solution Approach 2:
The patent changes the operational parameters of the mode locking laser by adjusting the longitudinal mode spacing and beat frequency to optimize the signal generation. By controlling the frequency parameters and using optical fiber length adjustment, the system generates the desired radio frequency signals while minimizing unwanted components.
2Adaptability or versatility
If multiple radar systems are equipped for comprehensive vehicle monitoring, then detection coverage is improved, but the cost increases significantly due to high cost RF parts
Solution Approach 1:
The patent implements a multi-functional radar system where a single mode locking laser oscillator serves multiple detection purposes. The same oscillator generates radio signals for detecting obstacles in front, sides, and back of the vehicle by adjusting the beam direction and frequency parameters, eliminating the need for separate oscillators for each detection zone.
Solution Approach 2:
The patent merges multiple radar detection functions into a single integrated system. By combining the oscillator, optical modulator, and signal processing components into one unified apparatus that can perform multiple detection tasks, the system reduces the overall number of RF parts and lowers the total cost while maintaining comprehensive detection coverage.
3Loss of energy
If the oscillator is positioned near the antenna to reduce transmission loss, then transmission efficiency is improved, but the oscillator reliability must be increased under severe circumstances
Solution Approach 1:
The patent replaces the traditional direct electrical connection between oscillator and antenna with an optical transmission medium (optical fiber). The mode locking laser generates optical signals that are transmitted through optical fiber to the antenna, eliminating the need for direct electrical connections and reducing the reliability requirements for the oscillator in harsh electromagnetic environments.
Solution Approach 2:
The patent introduces an optical fiber as an intermediary between the oscillator and the transmission antenna. This optical intermediary protects the oscillator from severe electromagnetic circumstances near the antenna while maintaining efficient signal transmission, as the optical fiber is immune to electromagnetic interference.
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 allows for cost reduction by eliminating the need for severe specification filters and high-performance amplifiers, enabling efficient generation and transmission of radio signals with improved power output and reduced unnecessary wave components, thus enhancing the practicality and affordability of radar systems for vehicle safety applications.
Implementation Method 1
an optical modulator for oscillation, a modulating means for inputting a modulating signal of a frequency of fm into the optical modulator to modulate a carrier wave so as to interpose sideband waves onto the carrier wave
Implementation Method 2
an optical receiver for oscillation for receiving beam radiated by the optical modulator and for converting the beam to electrical signal
Data Source
AI summary
It is provided a radio oscillating system for oscillating a radio signal. The system has an optical modulator for oscillation, a modulating means for inputting a modulating signal of a frequency of fm into the optical modulator to modulate a carrier wave so as to interpose sideband waves onto the carrier wave at positions shifted with respect to the frequency of the carrier wave by the frequency “fm”; and an optical receiver for oscillation for receiving beam from the optical modulator and converting the beam into an electrical signal. The system further has a radiating means for radiating radio signal of a frequency of 2fm based on the electrical signal. An input voltage Vp-p applied on the optical modulator is 1.0 times or more and 1.99 times or less of a half-wavelength voltage Vπ of the optical modulator.