MIMO Antenna Pattern Measurement Using Excess Probes
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Solution Overview
Problem
In radiated two-stage method measurements for MIMO devices, the channel matrix is not always invertible, leading to non-testable devices and inconclusive tests, which can be resolved by using more measurement antennas than the device under test has, ensuring the channel matrix is always invertible or pseudoinvertible.
Innovation Solution
A method involving a positioner to place the device under test, using a plurality of measurement antennas exceeding the number of device antennas to measure the antenna pattern, generating and inverting the channel matrix, and selecting the solution with the smallest Euclidean norm for reliable second-stage measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multiprobe anechoic chamber is used to ensure channel matrix invertibility, then measurement reliability is improved, but hardware costs and device complexity increase
Solution Approach 1:
The patent changes the parameter of measurement antenna quantity from the conventional equal number to a greater number than device antennas. This parameter change ensures the channel matrix is always invertible or pseudoinvertible without requiring complex multiprobe anechoic chambers, thus improving reliability while maintaining simple measurement setup
Solution Approach 2:
The patent applies excessive action by using more measurement antennas than the minimum required. This excess of measurement antennas guarantees channel matrix invertibility and allows for robust pseudo-inverse calculation, eliminating the need for expensive specialized equipment while ensuring measurement reliability
2Reliability
If the number of measurement antennas is increased beyond the number of device antennas, then channel matrix invertibility is ensured, but measurement setup complexity increases
Solution Approach 1:
The patent makes the measurement system universal by using a greater number of measurement antennas that can handle all possible device antenna configurations. This multi-functionality approach ensures the channel matrix is always invertible regardless of the specific device configuration, providing a robust solution that works for all MIMO devices without requiring specialized equipment
3Ease of operation
If standard channel matrix inversion is used, then measurement process is simple, but non-testable devices result when the channel matrix is not invertible
Solution Approach 1:
The patent performs preliminary action by ensuring channel matrix invertibility through excessive measurement antennas before the actual inversion process. This preliminary guarantee of invertibility allows standard inversion or pseudo-inverse methods to always produce valid results, eliminating non-testable devices while maintaining simple measurement processes
Solution Approach 2:
The patent implements feedback by using the measurements from excessive antennas to continuously ensure channel matrix invertibility. The measurement results from all antennas are fed back into the channel matrix calculation, allowing robust pseudo-inverse computation that always yields valid results, thus maintaining both simplicity and reliability
Data Source
Figure 1~2
AI summary
A method for performing a radiated two-stage method measurement on a device under test (12) having a predefined number of antennas (15), has the following steps: a) placing the device under test (12) on a positioner (20), b) establishing communication with the device under test (12) using at least one link antenna (22), c) measuring the antenna pattern of the device under test (12) using a plurality of measurement antennas (24), wherein the plurality of measurement antennas (24) comprise a number of measurement antennas (24) being larger than the number of antennas (15) of the device under test (12). Further, a measurement setup (10) is shown.