Sharing IFF Antenna Channel Between Interrogator and Transponder
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Solution Overview
Problem
The placement of omnidirectional antennas for IFF interrogators and transponders on naval ships is challenging due to structural obstructions, requiring separate antennas that complicate coverage and increase height requirements, while existing solutions like the BAE OE-120/UPX cylindrical antenna array do not allow shared use between interrogators and transponders.
Innovation Solution
A cylindrical antenna array with an omnidirectional channel is shared between the IFF interrogator and transponder using a radio-frequency switch or diplexer, allowing the antenna to be momentarily used by the interrogator for transmission and then available for the transponder, with optional circulators for signal isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate antennas are used for IFF interrogator and transponder to maintain omnidirectional coverage, then omnidirectional coverage is improved, but device complexity and placement difficulty increase
Solution Approach 1:
The patent combines the IFF interrogator and transponder functions into a single integrated antenna system. The interrogator and transponder share common antenna elements, eliminating the need for separate antennas while maintaining omnidirectional coverage through the cylindrical array geometry.
Solution Approach 2:
The antenna system is designed to perform multiple functions simultaneously - serving as both the interrogator antenna and transponder antenna. The same cylindrical array elements are used for both transmission and reception functions, making the system universal and reducing overall complexity.
2Ease of manufacture
If antenna is placed lower on the ship to avoid height requirements, then ease of installation is improved, but signal blocking and pattern distortion increase
Solution Approach 1:
The patent transitions from vertical antenna placement to a horizontal cylindrical arrangement around the mast. By distributing antenna elements around the circumference of the mast at a lower height, the system achieves omnidirectional coverage without requiring high vertical placement, avoiding signal blocking while maintaining installation ease.
3Reliability
If IFF interrogator uses omnidirectional channel for ISLS transmission, then ISLS capability is improved, but transponder transmission capability deteriorates
Solution Approach 1:
The patent implements time-division multiplexing where the omnidirectional channel is alternately assigned to the interrogator for ISLS transmission and to the transponder for reply transmission. The system periodically switches channel allocation based on operational phase, allowing both functions to access the omnidirectional capability at different times without permanent conflict.
Data Source
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AI summary
There is disclosed an apparatus for transmitting and receiving radiofrequency signals. The apparatus comprises a cylindrical antenna array, which comprises an omnidirectional channel. The apparatus comprises an IFF interrogator and an IFF transponder connected to the cylindrical antenna array. The apparatus comprises means for sharing the omnidirectional channel between the IFF interrogator and the IFF transponder.