Combination Tuning Probes for Load Pull Tuners
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Solution Overview
Problem
Existing load pull methods for testing microwave transistors lack the ability to achieve a large maximum to minimum frequency coverage and high tuning dynamic range without increasing the cost or requiring external mechanical intervention, and current tuning probes do not allow for independent vertical movement of slugs, limiting their frequency coverage and dynamic range.
Innovation Solution
A combination tuning probe is developed using two or more slugs, mounted on a mobile tuner carriage with independent vertical axes, allowing for smooth, continuous vertical movement and linked to prevent gaps that could cause resonances, thereby extending the frequency coverage and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single tuning probe is used, then the device complexity is low, but the frequency coverage range is limited
Solution Approach 1:
The tuning probe is segmented into multiple slugs (first slug, second slug, third slug) that can be independently positioned along the center conductor. Each slug can be adjusted to different positions to achieve different frequency coverage ranges, allowing the tuner to cover a broader frequency spectrum without requiring a completely different tuner structure.
Solution Approach 2:
Multiple slugs are nested along the same center conductor, with each slug capable of independent vertical movement. The slugs can be positioned at different heights to create overlapping frequency coverage, effectively nesting multiple tuning functions within a single probe structure.
2Adaptability or versatility
If the horizontal length of the probe is increased to increase maximum controllable capacitance, then the tuning dynamic range is improved, but the risk of short circuit increases
Solution Approach 1:
Instead of increasing the horizontal length of the probe, the invention transitions to vertical positioning of multiple slugs along the center conductor. The slugs can be moved independently in the vertical dimension to achieve the desired capacitance range without extending the horizontal footprint, thereby maintaining reliability while improving tuning dynamic range.
3Adaptability or versatility
If statically positioned multi slug tuning probes are used, then the tuning dynamic in certain frequency areas is increased, but the frequency coverage across all bands is limited
Solution Approach 1:
The slugs are made dynamically positionable along the center conductor rather than being statically fixed. Each slug can be independently adjusted to different vertical positions to optimize performance across different frequency bands, enabling continuous frequency coverage without requiring multiple fixed probe configurations.
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
The combination tuning probe achieves a broader frequency range, increasing the maximum to minimum frequency coverage by up to three decades without redesigning the tuner, while minimizing cost and mechanical intervention, and ensures continuous frequency coverage by maintaining contact between slugs.
Implementation Method 1
Since the tuning probe 34 is capacitively coupled with the center conductor 33
Implementation Method 2
Various types of resonant or combination tuning probes, including one or more slugs, have been reported before
Data Source
AI summary
Combination tuning probes for slide screw load pull tuners allow larger frequency coverage Fmax/Fmin and higher GAMMA beyond the capacity of existing tuning probes. This is done by combining two or more equally or unequally long tuning slugs into a combination probe, the slugs being mounted in the same mobile tuner carriage using two or more independent vertical axes. To avoid spurious resonance phenomena the tuning slugs are driven parallel vertically in close proximity or sliding on each-other, are linked to each-other and guided appropriately allowing smooth, un-inhibited and continuous vertical movement of the metallic bodies.