Tunable Microstrip Antenna Igniter for Off-Frequency Rejection
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Solution Overview
Problem
Existing ignition systems for energetic materials face challenges in achieving precise and repeatable energy release, are susceptible to time delay uncertainties due to long transmission distances, and require complex setups, while methods like laser and photoflash ignition have limitations in energy control and material compatibility.
Innovation Solution
A tunable microwave-initiated antenna igniter with microstrip antennas and a conductive material spanning a dielectric gap, allowing for frequency and bandwidth tuning to prevent accidental ignitions and enhance ignition efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive lead ignition systems are used, then ignition energy can be delivered, but time delay uncertainty increases due to long transmission distances
Solution Approach 1:
The patent replaces the mechanical/electrical conductive lead system with an electromagnetic field-based microwave ignition system. The microwave antenna delivers ignition energy through electromagnetic radiation rather than through conductive wires, eliminating the time delay and uncertainty associated with long transmission distances while maintaining reliable energy delivery to the energetic material.
2Measurement precision
If laser ignition is used, then timing control and energy fluence control are improved, but optical access requirements increase setup complexity
Solution Approach 1:
The patent changes the electromagnetic parameter from optical frequency (laser) to microwave frequency. This parameter change allows the ignition system to operate without stringent optical access requirements while maintaining precise timing control. The microwave antenna can deliver energy through materials and geometries that would block or complicate laser delivery, thereby reducing setup complexity.
3Temperature
If photoflash ignition with broadband radiation is used, then material heating is improved, but spectral property dependence causes uneven heating rates
Solution Approach 1:
The patent changes the radiation frequency parameter from broadband optical to narrowband microwave, and introduces a resonant antenna structure. The antenna is designed to resonate at a specific frequency that matches the absorption characteristics of the energetic material, creating a narrow bandwidth that targets specific molecular modes. This resonant coupling achieves efficient heating while maintaining uniform energy distribution, avoiding the spectral property dependence issues of broadband photoflash ignition.
4Reliability
If microwave ignition with dopant particles is used, then ignition sensitivity is improved, but composition modification increases manufacturing complexity
Solution Approach 1:
The patent replaces the approach of modifying material composition with dopant particles with a field-based solution using a resonant microwave antenna. Instead of changing the energetic material's composition to enhance microwave absorption, the antenna is designed to resonate at frequencies that naturally couple with the material's properties. This substitution maintains ignition sensitivity while avoiding the manufacturing complexity of composition modification.
5Reliability
If narrow bandwidth antenna is used, then frequency selectivity and accidental ignition rejection are improved, but ignition energy delivery efficiency may be reduced
Solution Approach 1:
The patent optimizes the antenna's resonant frequency and bandwidth parameters to achieve a balance between frequency selectivity and energy delivery efficiency. By tuning the antenna to resonate at the specific frequency where the energetic material has maximum absorption, the system achieves both narrow bandwidth (for accidental ignition rejection) and high efficiency (for energy delivery). The resonant coupling enhances the energy transfer at the target frequency while suppressing responses at other frequencies.
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 tunable microwave igniter provides precise and repeatable ignition with reduced complexity, rejecting off-frequency high-power fields and enabling efficient energy delivery.
Implementation Method 1
a pair of tunable microstrip antennas on a substrate configured to receive an electromagnetic radiation frequency that provides ignition energy
Implementation Method 2
a conductive material spanning a dielectric gap between the pair of tunable microstrip antennas
Data Source
AI summary
Disclosed is a tunable microwave-initiated antenna igniter. The device includes a pair of tunable microstrip antennas on a substrate configured to receive an electromagnetic radiation frequency that provides ignition energy; and a conductive material spanning a dielectric gap between the pair of tunable microstrip antennas. The conductive material spanning the dielectric gap can include a dielectric epoxy or a bridgewire. The microstrip antennas are tunable for frequency and bandwidth by varying dipole length and/or width. Tuning causes the microstrip antennas to reject accidental ignition from an off frequency high power microwave field. The tunability, bandwidth selectivity, and low energy requirements allow for use of the tunable microwave-initiated antenna igniters in a number of new and challenging ignition applications.