Antenna Duplexing Over Single Coax for RF and Thermal Constraints
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Solution Overview
Problem
Existing vehicle antenna and radio frequency front end (RFFE) systems face challenges due to high temperatures, increased weight, and cost from complex cable connections, which degrade performance and require bulky cooling solutions, especially in vehicles with multiple antennas and distributed RF circuits.
Innovation Solution
A single coaxial cable connection system is used to transmit DC-power, RF-signal, and control signal simultaneously, reducing the number of cables from four to one by employing time domain duplexing (TDD) and digital pre-distortion (DPD) to minimize weight, cost, and thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple cables are used to connect RFFE to antennas, then reliability of connection is improved, but weight and cost increase significantly
Solution Approach 1:
The patent combines multiple separate cable functions (DC power, RF signal, control signals) into a single integrated coaxial cable system. The single cable includes multiple conductors that simultaneously carry power, data, and RF signals, eliminating the need for separate cables for each function while maintaining reliable connections between the RFFE and antenna front end.
Solution Approach 2:
The single coaxial cable is designed to perform multiple functions simultaneously: it provides DC power delivery, transmits bidirectional control signals for operational mode switching, and carries RF signals for communication. This multi-functional cable replaces what would traditionally require three or more separate cables, reducing weight while maintaining system reliability.
2Temperature
If RFFE is separated from antenna front end, then thermal stress on electronics is reduced, but device complexity increases due to multiple cables
Solution Approach 1:
The patent merges multiple cable functions into a single integrated cable system that connects the separated RFFE and antenna front end. This single cable carries power, control, and RF signals simultaneously, reducing the complexity of cable distribution while maintaining the thermal separation benefits of having RFFE and antenna front end in different locations.
Solution Approach 2:
The single multi-functional cable acts as an intermediary that bridges the separated RFFE and antenna front end components. It enables communication and power delivery across the thermal boundary without requiring multiple separate connection paths, simplifying the overall system architecture while maintaining component separation for thermal management.
3Ease of manufacture
If coaxial cables are used for RF connections, then ease of manufacture is improved, but insertion loss at RF/microwave frequencies increases
Solution Approach 1:
The patent optimizes the coaxial cable parameters specifically for RF and microwave frequencies, including conductor material selection, insulation properties, and geometric dimensions. These parameter changes minimize RF signal attenuation and insertion loss while maintaining ease of manufacture and compatibility with standard connectors and interfaces.
4Reliability
If waveguides are used for distributed RF connections, then RF signal transmission is improved, but flexibility and adaptability to vehicle curves decrease
Solution Approach 1:
The coaxial cable system serves as a flexible intermediary that can be routed along vehicle surfaces and curves to connect distributed RF elements. Unlike rigid waveguides, the coaxial cable maintains signal integrity while adapting to the complex geometries of vehicle bodies, providing both RF performance and installation flexibility.
Data Source
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AI summary
A radio frequency front end and an antenna front end may be separated from one another to maintain close proximity between a low noise amplifier and an antenna while achieving improved thermal regulation of a power amplifier. The radio frequency front end antenna front end may include a duplexing system that enables operation with a single electrical cable. Furthermore, where it is desired to transmit a radiofrequency signal via a waveguide, a flexible waveguide may be constructed with a distributed capacitance between waveguide protrusions.