Variable Ratio Power Divider for Dual Polarization Radar Calibration
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Solution Overview
Problem
Dual polarization radar systems face challenges in regular calibration and power balancing between horizontal and vertical transmit channels, with existing methods being limited by weather conditions and inability to perform calibration at desired times or intervals.
Innovation Solution
A variable ratio power divider is used to split and adjust calibration signals for dual polarization radar systems, allowing for precise balancing of power between horizontal and vertical channels, enabling self-calibration and testing at any time using a built-in test equipment that simulates polarimetric radar signals and injects them into the antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bird bathing calibration method is used, then calibration can be performed using natural rainfall, but it can only be performed during light-to-medium strataform rainfall and not on a regular basis
Solution Approach 1:
A variable ratio power divider is introduced as an intermediary device between the signal source and the horizontal/vertical transmit channels. This power divider actively controls the distribution of calibration signals to compensate for unequal losses in the transmit channels, enabling regular calibration without dependence on natural rainfall conditions.
Solution Approach 2:
The radar system incorporates built-in test equipment that generates calibration signals and uses the variable ratio power divider to automatically balance power between channels. This self-calibration capability eliminates the need for external calibration equipment and allows the system to perform calibration at any time without human intervention.
2Measurement precision
If sun tracking calibration method is used, then receiver calibration can be performed, but there are only short periods each day when accurate calibration can be made
Solution Approach 1:
The system performs calibration using built-in test equipment that generates signals in advance, eliminating the need to wait for specific external conditions like sun positioning. The variable ratio power divider pre-balances the power distribution, allowing calibration to be performed at any time rather than waiting for optimal external conditions.
Solution Approach 2:
The variable ratio power divider acts as an active intermediary that compensates for channel imbalances through controlled signal distribution. This eliminates the time constraints associated with passive calibration methods that depend on external conditions, providing continuous calibration capability.
3Adaptability or versatility
If built-in test equipment with variable ratio power divider is used, then regular calibration can be performed at any time, but the device complexity increases
Solution Approach 1:
The variable ratio power divider serves multiple functions: it divides calibration signals between horizontal and vertical channels, actively balances power to compensate for channel losses, and enables both transmitter and receiver calibration. This multi-functionality justifies the added complexity by consolidating several calibration requirements into a single device.
Solution Approach 2:
The built-in test equipment with variable ratio power divider creates a self-calibrating system that eliminates the need for external calibration equipment and personnel. The system performs its own calibration at regular intervals, making the complexity worthwhile by achieving operational autonomy and consistent calibration quality.
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 system achieves precise balancing of transmitted power between channels, allowing for reliable and regular calibration and testing, with results demonstrating better than 1/20th of a decibel accuracy, and enables the radar to function autonomously without external equipment.
Implementation Method 1
a waveguide switch that receives the first test signal; where the waveguide switch may be configured to operate in an first position and pass the first test signal through a variable 0°-180° phase shifter
Implementation Method 2
pass the first test signal through a variable 0°-180° phase shifter so that the power of the first and second test signals is evenly divided
Data Source
AI summary
A variable ratio power divider (VRPD) used for adjusting a calibration signal for a dual polarization radar system has been developed. The VRPD includes an input line that receives a calibration signal and splits the calibration signal into two separate test signals that have a 0° phase shift between them. The VRPD also includes a horizontal polarization output port for a horizontal calibration signal and a vertical polarization output port for a vertical calibration signal. A waveguide switch receives one of the test signals. If the waveguide switch is operating in a first position, it passes the test signal through a variable 0°-180° phase shifter. This evenly divides the power of the test signals between the horizontal and vertical output ports. If the waveguide switch is operating in a second position, it causes the test signal to bypass the phase shifter so that the entire power of the both test signals is directed entirely to either the horizontal phase output port or the vertical phase output port.