Antenna Switch Harmonic Distortion Compensation
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Solution Overview
Problem
Mobile phone antenna switches formed on silicon substrates face challenges in minimizing harmonic distortion due to higher parasitic capacitance and increased costs compared to compound semiconductor substrates, which are costly and inefficient for multi-functional mobile devices requiring compatibility with various frequency bands and modulation methods.
Innovation Solution
Incorporating a capacitance circuit with a voltage-dependent capacitance that decreases when positive or negative voltage is applied between the source and drain regions of field effect transistors, effectively compensating for parasitic capacitance and reducing harmonic distortion, thereby minimizing the impact of harmonic distortion in antenna switches on silicon substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a field effect transistor is formed over a silicon substrate to reduce cost, then the cost of the antenna switch is reduced, but the parasitic capacitance increases and harmonic distortion becomes larger
Solution Approach 1:
The invention converts the harmful voltage dependency of parasitic capacitance into a beneficial effect by introducing a compensation capacitance circuit with opposite voltage dependency characteristics. This circuit generates a compensating effect that counteracts the harmonic distortion caused by the silicon substrate's parasitic capacitance, thereby transforming the originally harmful capacitance variation into a useful distortion compensation mechanism
Solution Approach 2:
The invention introduces a compensation capacitance circuit as an intermediary element between the field effect transistor and the antenna terminal. This intermediary circuit has voltage-dependent capacitance characteristics that are opposite to those of the parasitic capacitance, serving as a mediator to cancel out the harmful effects of parasitic capacitance without requiring changes to the fundamental silicon substrate architecture
2Object-generated harmful factors
If a field effect transistor is formed over a compound semiconductor substrate to reduce harmonic distortion, then the linearity and RF characteristics are improved, but the cost increases
Solution Approach 1:
The invention replaces expensive compound semiconductor substrates with inexpensive silicon substrates, accepting the trade-off of higher parasitic capacitance. The solution compensates for this deficiency through an additional compensation capacitance circuit, effectively achieving low harmonic distortion performance at a fraction of the cost of compound semiconductor-based solutions
Solution Approach 2:
The invention changes the operational parameters of the antenna switch by introducing a voltage-dependent compensation capacitance that dynamically adjusts to counteract parasitic capacitance effects. This parameter-based approach allows silicon substrate-based transistors to achieve performance characteristics previously only available from expensive compound semiconductor devices
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 solution reduces harmonic distortion in antenna switches on silicon substrates, enhancing their performance and reducing costs while maintaining compatibility with multiple frequency bands and modulation methods, thus addressing the limitations of existing technologies.
Implementation Method 1
a capacitance circuit which has a voltage dependency such that, in either of cases where a positive voltage is applied to the drain region based on a potential of the source region and where a negative voltage is applied to the drain region based on the potential of the source region, a capacitance decreases to a value smaller than that in a state where the potential of the source region and a potential of the drain region are at the same level
Data Source
AI summary
In terms of achieving a reduction in the cost of an antenna switch, there is provided a technology capable of minimizing harmonic distortion generated in the antenna switch even when the antenna switch is particularly formed of field effect transistors formed over a silicon substrate. Between the source region and the drain region of each of a plurality of MISFETs coupled in series, a distortion compensating capacitance circuit is coupled which has a voltage dependency such that, in either of the cases where a positive voltage is applied to the drain region based on the potential of the source region and where a negative voltage is applied to the drain region based on the potential of the source region, the capacitance decreases to a value smaller than that in a state where the potential of the source region and the potential of the drain region are at the same level.