Conformal RF Antenna Array With Integrated EME Rejection Filter
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Solution Overview
Problem
Conformal RF antenna arrays face challenges in integrating out-of-band EME rejection filters due to space constraints and the need for larger connectors to handle high EME emissions, which occupy valuable vehicle space and complicate manufacturing.
Innovation Solution
An integrated conformal antenna array with an out-of-band rejection filter is fabricated on a multi-layer board that conforms to a curved surface, incorporating a feed network and rejection filter to handle EME emissions, allowing the use of smaller connectors based on transmit power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a larger connector is used to handle high EME emissions, then the connector can withstand higher power levels, but it occupies more vehicle space
Solution Approach 1:
The patent combines the EME rejection filter with the antenna feed network into a single integrated structure. The filter is implemented as additional trace patterns on the same substrate as the feed network, eliminating the need for separate filter components and allowing compact connector design that handles both high power EME emissions and in-band signals without requiring oversized connectors
Solution Approach 2:
The patent introduces an EME rejection filter as an intermediary component between the antenna elements and the connector. This filter selectively attenuates out-of-band EME emissions while allowing in-band signals to pass through, enabling the use of smaller connectors that would otherwise be unable to handle the full power of unfiltered EME emissions
2Object-affected harmful factors
If an out-of-band rejection filter is integrated into the conformal antenna array, then EME emissions are rejected, but the manufacturing complexity increases
Solution Approach 1:
The EME rejection filter is merged with the antenna feed network by implementing both functions using the same microstrip trace patterns on the conformal substrate. The filter consists of additional trace geometries (such as parallel plates or resonant structures) that are fabricated simultaneously with the feed network in a single PCB manufacturing process, eliminating the need for separate filter components and complex assembly steps
Solution Approach 2:
The patent implements the EME rejection filter by changing the geometric parameters of the microstrip traces. By adjusting trace width, spacing, length, and positioning, the filter characteristics (cutoff frequency, attenuation level) are controlled through standard PCB fabrication parameters that can be easily adjusted during the manufacturing process without requiring new fabrication techniques
3Volume of moving object
If the antenna elements are made small for conformal mounting, then the aerodynamic drag is reduced, but the fabrication tolerances become difficult to achieve
Solution Approach 1:
The patent uses parametric design of the microstrip antenna elements where the electrical performance is controlled by trace dimensions (width, length, spacing) rather than physical size. This allows small conformal elements to be designed with tolerances that are achievable with standard PCB fabrication processes, as the critical parameters are trace geometries that can be controlled within typical manufacturing variations
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 solution reduces the size of connectors and minimizes space usage while effectively protecting the RF connector and radio from EME emissions, enabling efficient operation in high-speed vehicles.
Implementation Method 1
an out-of-band rejection filter integrated into the conformal antenna array and configured to block EME (ElectroMagnetic Environment) emissions
Implementation Method 2
the nondirection radio waves emitted by the individual antennas can be made to combine in front of the antenna through interference, form a strong beam (or beams) or radio waves pointed in any desired direction
Implementation Method 3
The phase shifters also compensate for the different phase shifts caused by the varying path lengths of the radio waves due to the location of the individual antennas on the curved surface
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A datalink such as used on high-speed vehicles (missiles, guided-projectiles, manned or unmanned aircraft) includes an integrated conformal antenna array and out-of-band rejection filter for use with an RF radio. Integration of a single rejection filter between the EME power received by the antenna array and the coaxial RF connector effectively protects the connector as well as the radio. The connector can now be designed based solely on the transmit power requirements of the radio. The resultant connector is smaller and takes up less space inside the vehicle.