Cloud Radar Antenna Keying for Blind Area Reduction
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Solution Overview
Problem
Conventional cloud radars using millimeter waves face limitations in detecting fog and cloud layers close to the ground and above, due to restricted transmission power and the need for separate antennas, which results in blind areas and reduced sensitivity, especially when trying to measure up to 10 km altitude with a compact design.
Innovation Solution
A radar device that uses a linearly frequency-modulated continuous-wave signal with targeted signal interruption, allowing for a common antenna structure and optimized keying of the transmission signal to achieve high sensitivity and avoid blind areas, while maintaining low transmission power and protecting the receiver from interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate transmitting and receiving antennas are used to improve sensitivity and avoid blind areas, then detection reliability is improved, but device complexity and compactness are worsened
Solution Approach 1:
The patent combines the transmitting and receiving antennas into a single antenna structure, eliminating the need for separate antennas. This merging approach maintains detection reliability by using a single antenna for both functions while achieving the desired compact design without the complexity of multiple antenna systems
Solution Approach 2:
The single antenna is designed to serve multiple functions - both transmitting and receiving electromagnetic waves. This multi-functional antenna replaces the need for dedicated transmitting and receiving antennas, reducing device complexity while maintaining the ability to detect fog and cloud layers effectively
2Use of energy by moving object
If continuous wave transmission is used to maximize power utilization, then transmission power efficiency is improved, but receiver interference from transmit signals is worsened
Solution Approach 1:
The patent implements periodic interruption of the continuous wave transmission signal. The transmission is switched on and off in cycles, creating distinct transmit phases and receive phases. This periodic action allows the receiver to be protected from transmit signal interference during receive phases while maintaining good power utilization during active transmit phases
Solution Approach 2:
The transmission signal is interrupted in advance before the receiver needs to detect the echo signal. By switching off the transmission proactively during receive phases, the system prevents receiver interference before it occurs, ensuring clean signal detection while maintaining overall power efficiency
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
Enables complete detection of fog and cloud phenomena up to 10 km altitude with reduced blind areas, using a compact design and low transmission power, while maintaining the sensitivity and range of cloud radars, and effectively separating distance and speed measurements within the Nyquist interval.
Implementation Method 1
The instantaneous frequency of the voltage-controlled oscillator can be varied in different ways, for example, in a sawtooth pattern with a period T
Implementation Method 2
A cloud radar emits focused electromagnetic waves that are scattered by objects or particles, particularly water droplets or ice crystals, in the atmosphere
Implementation Method 3
both the distance and the velocity of the scattering objects lead to a frequency shift
Implementation Method 4
The location of the scattering object can be determined from the echo's travel time
Data Source
Figure 1~2
Figure 3a~3b
AI summary
Radar device and method for determining fog and cloud parameters in the atmosphere using millimeter waves, comprising a transmitter for generating a frequency-modulated transmit signal, which is emitted via a transmitting antenna (1a), and a receiver, to which an echo signal is fed via a receiving antenna (1b). This echo signal is generated by reflection of the transmit signal off liquid droplets and/or ice crystals. The receiver includes a mixer (6) to which the received echo signal, amplified by a preamplifier (10), can be fed, and by which the amplified echo signal can be converted into a low-frequency receive signal. Furthermore, a signal processor unit (11) is provided, which can generate altitude-resolved information (13) about the properties of fog and/or cloud phenomena occurring in the atmosphere.The described technical solution is characterized by the fact that the transmit signal can be interrupted for a transmit pause (18) after a transmit phase (17), wherein the receiver is at least partially deactivated during the transmit phase (17) of the transmit signal and activated during the transmit pause (18), and that a key signal (14) is generated by a signal generation unit (12) and is used as the basis for controlling at least one electronic component of the transmitter and/or the receiver, so that the interruption of the transmit signal in the transmitter and a sampling of the echo and/or receive signal in the receiver are controlled in such a way that a time interval (15) formed by adding the transmit phase (17) and the transmit pause (18) of the transmit signal is equal to a period of sampling of the echo and/or receive signal in the receiver.