Active Antenna Intermodulation Distortion Self-Test System
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Solution Overview
Problem
Active antenna systems face challenges in determining intermodulation distortion (IMD) performance due to the lack of connectorized 50Ω ports, which are required for traditional IMD testing, and need a method to validate and monitor IMD and passive intermodulation (PIM) performance over their lifetime without external test equipment.
Innovation Solution
An active antenna test system with a test signal generator, transmitter modules, and an intermodulation determination module that generates test signals, processes them through the antenna system, and determines IMD performance, allowing for self-testing and self-healing capabilities without external equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional IMD testing techniques are used with connectorized 50Ω ports, then IMD performance can be measured, but active antenna systems cannot be tested because they lack such ports
Solution Approach 1:
The patent introduces an intermediary testing mechanism that couples transmitter modules to receiver modules through the antenna system's internal signal paths. This intermediary approach enables IMD measurement without requiring external connectorized ports, as the test signals are injected and measured through the system's existing RF interfaces and signal processing chains.
Solution Approach 2:
The active antenna system performs self-testing by using its own transmitter modules to generate test signals and its own receiver modules to measure IMD products. The system's internal components serve both as the test equipment and the device under test, eliminating the need for external testing equipment and adapting traditional IMD measurement concepts to systems without conventional test ports.
2Reliability
If passive antenna systems are tested for PIM performance using external equipment, then PIM degradation can be detected, but active antenna systems require complex external test setups
Solution Approach 1:
The active antenna system monitors its own PIM performance by using internal transmitter and receiver modules to generate and measure intermodulation products. The system periodically performs self-diagnostics without requiring external test equipment, enabling continuous reliability monitoring while minimizing testing complexity.
Solution Approach 2:
The system implements feedback mechanisms where measurement results from internal IMD testing are fed back to the control module. This feedback enables the system to track PIM performance degradation over time, identify problematic components, and trigger maintenance alerts, creating a closed-loop reliability monitoring system.
3Measurement precision
If transmitter modules are continuously monitored for IMD contribution, then individual module performance can be identified, but testing time increases
Solution Approach 1:
The patent segments the IMD measurement process by testing individual transmitter modules separately. Each module is sequentially coupled to the test signal generator while others remain uncoupled, allowing precise identification of each module's IMD contribution. This segmentation enables targeted maintenance decisions without requiring full-system disassembly or complex multi-module simultaneous testing.
Solution Approach 2:
The system employs periodic testing where transmitter modules are sequentially activated and tested in a repeating cycle. Each module undergoes IMD measurement during its designated time slot, and the process repeats for all modules. This periodic approach balances measurement precision with time efficiency by systematically rotating through modules rather than attempting simultaneous measurement.
Data Source
AI summary
An active antenna test system comprising an active antenna unit comprising: a test signal generator arranged to generate at least a first test signal and at least one second test signal; a plurality of transmitter modules operably coupled to the test signal generator wherein the plurality of transmitter modules are arranged to simultaneously process the first test signal and at least one second test signal to produce at least one radio frequency test signal therefrom; and at least one receiver module arranged to process one or more signals falling in at least one spectral band determined to be susceptible to intermodulation distortion products caused by the at least one radio frequency test signal being generated from the first test signal and at least one second test signal; and an intermodulation determination module operably coupled to the at least one receiver module and arranged to determine a first received intermodulation performance. A first transmitter module of the plurality of transmitter modules is operably uncoupled from the test signal generator and at least a first test signal and at least one second test signal re-applied to the remaining transmitter modules, such that the intermodulation determination module determines a second received intermodulation performance in order to determine an intermodulation distortion contribution of the first transmitter module therefrom.