Passive Radar Response System Using Microwave Switch Modulation
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Solution Overview
Problem
Conventional radar response systems are complex, expensive, energy-intensive, and detectable due to active oscillators, making them unsuitable for applications requiring low volume, mass, and power consumption, particularly in airborne environments where maintenance is frequent.
Innovation Solution
A passive radar response system utilizing a microwave switch connected to two distinct impedance microwave lines and a generator for configurable pilot signal modulation, allowing adjustable amplitude and phase modulation of backscattered signals, reducing energy consumption and eliminating active emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If active oscillators are used to generate microwave signals for radar response, then the system can actively communicate with the radar, but the system becomes detectable and energy-intensive
Solution Approach 1:
Instead of actively generating microwave signals to communicate with radar, the invention inverts the approach by passively receiving radar signals and modulating them for reflection back to the radar. This eliminates the need for active oscillators and microwave generation, making the system undetectable while maintaining communication capability
Solution Approach 2:
The invention replaces the electronic/microwave system (active oscillators generating microwave signals) with a mechanical modulation system. The modulation is achieved through physical movement of the antenna or reflector surface, converting electromagnetic signal generation into a mechanical positioning problem
2Ease of operation
If active oscillators and microwave signal generation components are used, then the system can respond to radar signals, but the device complexity and production cost increase
Solution Approach 1:
The invention extracts and removes the complex microwave signal generation components (active oscillators, frequency modulators, amplifiers) from the system. Only the essential passive antenna and simple modulation mechanism remain, dramatically reducing component count and system complexity
Solution Approach 2:
The invention replaces expensive, complex active microwave components with simple, inexpensive passive elements. The system uses basic antenna structures and simple mechanical or electronic switching mechanisms that are far cheaper and more reliable than active oscillator systems
3Ease of operation
If active microwave signal generation is used, then the system can synchronize with radar signals, but energy consumption increases requiring mains power supply
Solution Approach 1:
The invention uses periodic modulation of the passive antenna system to achieve synchronization with radar signals. Instead of continuously generating microwave signals, the system periodically modulates the reflected signal at the same frequency as the radar, achieving synchronization without continuous high energy consumption
Solution Approach 2:
Instead of actively generating and synchronizing microwave signals (energy-intensive), the system inverts the approach by passively receiving radar signals and modulating their reflection. This eliminates the need for high-power microwave generation while maintaining synchronization capability
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 low production costs, autonomy, and ease of integration with minimal detectability, enabling precise detection and localization of cooperative targets with reduced energy consumption and maintenance needs.
Implementation Method 1
a passive antenna capable of receiving then backscattering a signal emitted by said radar
Implementation Method 2
a microwave type switch connected to said antenna, at least two microwave lines each having a distinct impedance and being connected to the microwave switch
Implementation Method 3
a generator capable of generating a configurable pilot signal, to the microwave switch so that it switches to one or the other of the microwave lines, so as to modulate the signal backscattered by said antenna
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a system for responding to a signal emitted by a radar. It comprises: - a passive antenna (ANT) capable of receiving and then backscattering a signal emitted by said radar, - a microwave switch (COM) connected to said antenna, - at least two microwave lines (LHF1, LHF2) each having a distinct impedance and being connected to the microwave switch, and - a generator (GEN) capable of generating a configurable control signal, to the microwave switch so that it switches on one or the other of the microwave lines, so as to modulate the signal backscattered by said antenna, two successive microwave lines having a difference in length equal to λ/2, λ being the wavelength of the signal received by the antenna.