Millimeter Wave Load Pull Phase Amplitude Tuning
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Solution Overview
Problem
Existing load pull systems for millimeter wave frequencies face challenges in controlling phase and amplitude due to limited and expensive RF sources, which results in phase jitter and impedance jitter, affecting measurement accuracy.
Innovation Solution
The solution involves controlling amplitude and phase at low frequencies and then upconverting the signals to millimeter wave frequencies using a millimeter wave extender or multiplier or mixer, eliminating phase jitter by using a single RF source split into multiple signals with independent phase and amplitude control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RF sources are used to control phase and amplitude at millimeter wave frequencies, then active tuning capability is achieved, but phase jitter and impedance jitter occur due to limited and expensive RF sources
Solution Approach 1:
The system separates phase and amplitude control into two independent domains: low-frequency control signals and high-frequency RF signals. The low-frequency signal controls the phase and amplitude, while the high-frequency RF signal provides the carrier. This segmentation eliminates phase jitter because the control signal does not operate at the same frequency as the RF signal, preventing interference and instability.
Solution Approach 2:
A low-frequency control signal acts as an intermediary between the control system and the high-frequency RF signal. This intermediary signal modulates the phase and amplitude of the RF signal without directly operating at millimeter wave frequencies, thereby avoiding the limitations and instabilities of high-frequency RF sources while maintaining precise control capability.
2Adaptability or versatility
If multiple RF sources are used for active load pull at multiple frequencies, then simultaneous tuning capability is improved, but system complexity and cost increase
Solution Approach 1:
The low-frequency control signal serves multiple functions: it controls phase, controls amplitude, and can be extended to control multiple frequencies simultaneously. By using a single low-frequency source that can be frequency-divided or modulated, the system achieves multi-frequency active load pull capability without requiring multiple independent high-frequency RF sources, thereby reducing system complexity and cost.
Solution Approach 2:
The system transitions from controlling multiple high-frequency RF signals in the time domain to controlling a single low-frequency signal that inherently provides multi-frequency capability through frequency division or modulation. This dimensional change from high-frequency multiple signals to low-frequency single signal with spectral expansion resolves the contradiction between versatility and complexity.
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
This approach allows for accurate active tuning at millimeter wave frequencies with reduced phase jitter, improving measurement reliability and data accuracy by maintaining stable impedance settings.
Implementation Method 1
upconverting the signals to millimeter wave frequencies using a millimeter wave extender or multiplier or mixer
Data Source
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AI summary
A load pull system for making measurements on a OUT at millimeter wave frequencies using active tuning. The system uses phase and amplitude control (2, 2A, 3, 3A, 9, 9A) of each signal at low frequency before being up-converted (7, 7A) to the millimeter wave measurement frequencies. The measured signals at the OUT plane may be downconverted (9, 9A) for measurement with a low frequency analyzer.