Shared Low Noise Amplifier for Dual Patch Antennas
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high cost of low noise amplifiers (LNAs) and coaxial cables in dual-frequency radio receiver systems, particularly when used in compact antenna assemblies for vehicles, necessitates a more economical solution for signal amplification and transmission while maintaining signal integrity.
Innovation Solution
A compact antenna assembly design that shares a single low noise amplifier for both patch antennas tuned to different frequencies, utilizing a transmission line with specific impedance characteristics to minimize interference and achieve isolation between the antennas, allowing a single coaxial cable to communicate amplified signals to a splitter or diplexer for separate reception by SDARS and GPS receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate LNAs and coaxial cables are used for each patch antenna in dual-frequency systems, then signal integrity is maintained, but system cost increases significantly
Solution Approach 1:
The patent combines two separate LNAs into a single shared LNA that serves both patch antennas. The amplified signals from both antennas are combined at the LNA output and then separated by a diplexer into different frequency bands (SDARS and GPS). This merging approach reduces component count and cost while maintaining signal integrity through proper impedance matching and isolation techniques.
Solution Approach 2:
The single LNA is designed to universally amplify signals from both patch antennas across different frequency bands. The LNA performs multiple functions: amplifying SDARS signals from one antenna, amplifying GPS signals from another antenna, and handling the combined output. This multi-functionality reduces system complexity and cost while maintaining the reliability needed for dual-frequency operation.
2Device complexity
If a single LNA is shared between both patch antennas, then system cost is reduced, but signal isolation between different frequencies becomes challenging
Solution Approach 1:
The patent introduces a diplexer as an intermediary device between the shared LNA and the two patch antennas. The diplexer acts as a frequency-selective mediator that directs SDARS frequency signals to one antenna and GPS frequency signals to the other antenna. This intermediary component ensures proper signal isolation and routing, preventing interference between the two frequency bands while allowing the single LNA to serve both antennas effectively.
Solution Approach 2:
The patent utilizes frequency parameter changes to achieve signal isolation. By designing the patch antennas and diplexer with specific resonant frequencies for SDARS and GPS bands, the system naturally isolates different frequency signals. The impedance characteristics and electrical lengths of transmission lines are carefully selected to provide proper isolation at different frequencies, allowing the single LNA to amplify both signals without interference.
Data Source
AI summary
According to various exemplary embodiments, an antenna assembly generally includes a first patch antenna and a second patch antenna. The first patch antenna may include a first feed point and be tuned to a first frequency. The second patch antenna may include a second feed point and be tuned to a second frequency. The antenna assembly may further include a low noise amplifier in communication with the first and second feed points of the respective first and second patch antennas for amplifying signals received by the first and second patch antennas.