Compact Multiband Helical Antenna for Stealth Sensors
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Solution Overview
Problem
Existing multiband antennas for unmanned ground sensors are too large and easily detectable, failing to provide adequate isolation and adaptability across multiple frequency ranges while maintaining a small, inconspicuous profile.
Innovation Solution
A compact multiband antenna system featuring a helical antenna with a coaxial conductor and an associated sub-system, utilizing a conformable coaxial cable, toroid-based isolation network, and a double-dipole antenna configuration to achieve wideband operation and concealment, allowing for operation across 225 MHz to 6 GHz with low VSWR and high gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing multiband antennas are used for unmanned ground sensors, then multiple frequency ranges can be operated, but the antenna size becomes large and easily detectable
Solution Approach 1:
The patent implements nesting by placing the first antenna element inside the second antenna element. The inner antenna (first element) is positioned within the structure of the outer antenna (second element), allowing both antennas to occupy the same spatial envelope. This nested configuration enables multiband operation while maintaining a compact overall antenna size that is suitable for concealed deployment on unmanned ground sensors.
2Adaptability or versatility
If existing multiband antennas are used for unmanned ground sensors, then multiple frequency ranges can be operated, but the antenna becomes easily detectable
Solution Approach 1:
The nested configuration allows the antenna system to maintain a compact, inconspicuous profile that is difficult to detect. By placing one antenna inside another, the overall structure remains small and can be easily concealed on unmanned ground sensors, thereby reducing detectability while preserving multiband operational capability.
3Volume of moving object
If antenna elements are placed close together for compact size, then small profile is achieved, but isolation between frequency bands deteriorates
Solution Approach 1:
The patent applies local quality by providing selective grounding of the antenna elements. The first antenna element is grounded at its distal end, while the second antenna element is grounded at its proximal end. This asymmetric grounding arrangement creates different electrical characteristics for each element, enabling frequency separation and improved isolation between bands despite the compact nested configuration. Each element is optimized for its specific frequency range through this localized grounding strategy.
Data Source
AI summary
A multiband antenna system includes a helical antenna having a first leg and a second leg wherein the first leg consists of a coaxial conductor. The multiband antenna also includes an antenna sub-system coupled to the helical antenna wherein the coaxial conductor feeds the antenna sub-system. A radome encloses components of the antenna system, and the radome may be covered by a radio-frequency transparent sock for concealment purposes.