RF Feed-Through Antenna for Shielded Aircraft Fuselage
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Solution Overview
Problem
The shielding of a mobile platform, such as an aircraft fuselage, prevents wireless devices on board from directly connecting with remotely located wireless access points, requiring them to use the aircraft's on-board network for connectivity.
Innovation Solution
A system with a first antenna inside the mobile platform and a second antenna on its exterior surface, connected by conductive cabling and an RF switch, allows direct wireless connection to remotely located access points without relying on the on-board network, using amplifiers and filters to enhance signal quality and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuselage is shielded to protect passengers and equipment, then safety and electromagnetic protection are improved, but wireless connectivity to external access points deteriorates
Solution Approach 1:
A feed-through antenna system acts as an intermediary between the shielded interior and external wireless networks. The antenna extends through the fuselage shielding, with an internal element coupled to coaxial cable that penetrates the fuselage wall, allowing RF signals to pass through the shielded boundary without compromising overall shielding effectiveness.
Solution Approach 2:
The antenna system is segmented into internal and external portions. The internal antenna element is positioned within the shielded volume and coupled to coaxial cable that extends through the fuselage wall to an external antenna element, dividing the antenna function across the shielding boundary to enable both shielding and wireless connectivity.
2Reliability
If the on-board network is used for wireless connectivity, then network security and isolation are improved, but device complexity and cost increase
Solution Approach 1:
The wireless connectivity function is extracted from the on-board network infrastructure and provided directly through feed-through antennas. This eliminates the need for complex on-board network equipment, servers, and routing infrastructure while maintaining network security by allowing direct connection to external access points.
Solution Approach 2:
The aircraft fuselage itself provides the wireless connectivity service through integrated feed-through antennas, eliminating the need for separate on-board network systems. The antenna system directly enables wireless communication between passenger devices and external access points without requiring intermediate on-board networking equipment.
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
Enables two-way wireless connectivity for users on a shielded mobile platform with remotely located access points without needing the on-board network, providing more direct and potentially lower-cost access while maintaining network security and isolation.
Implementation Method 1
Conductive cabling connects the two antennae to a control system that completes or interrupts the circuit path between the two antennae
Implementation Method 2
the body of the mobile platform is shielded and would otherwise block the passage of RF signals into or out from the interior area of the mobile platform
Data Source
AI summary
A system and method for selectively enabling and disabling wireless connectivity between cellular or PDA users on-board commercial aircraft having a shielded fuselage, and remotely located wireless access points, while the aircraft is at an airport or airfield. The system and method does not require access to an on-board LAN system of the aircraft. The system includes one or more antennae disposed in the cabin area of the aircraft that are coupled via an RF switch with an exterior antenna mounted on an exterior of the fuselage. The RF switch is controlled by a switch control subsystem, and enables or disables communication between the interior antennae and the exterior antenna. The exterior antenna is connected to the switch via a conductor that extends through the shielding of the aircraft. When the RF switch is in the closed position, cellular or PDA users can connect through the interior antennae and the exterior antenna directly to remotely located wireless access points.