Semiconductor Switching Device for Harmonic Rejection
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Solution Overview
Problem
Antenna switches for 3G and 4G applications face stringent harmonic rejection requirements, particularly for RF signals with high input power, where existing technologies struggle to maintain second harmonics below -70 dBm, leading to inefficiencies in routing RF signals effectively.
Innovation Solution
The design incorporates a switching device with switch cells configured similarly, each comprising a cascode connection of MOSFETs with specific doping regions and PIN diodes, which model resistance and capacitance variations non-linearly with voltage, reducing harmonic power by controlling channel inversion charges and depletion regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional antenna switch designs are used, then the device can route RF signals, but the second harmonics exceed -70 dBm requirement
Solution Approach 1:
The patent applies local quality by creating non-uniform doping concentrations within the channel region. Specifically, a first doping region with lower concentration and a second doping region with higher concentration are formed at different locations along the channel, allowing different parts of the transistor to contribute differently to harmonic suppression while maintaining overall switching functionality.
Solution Approach 2:
The patent changes the doping concentration parameter along the channel length to suppress harmonics. By varying the dopant concentration from the first region to the second region, the electrical characteristics of the channel are modified to reduce second harmonic generation while preserving the RF signal routing capability.
2Power
If high input RF power is processed, then signal routing capability is maintained, but harmonic rejection becomes more difficult to achieve
Solution Approach 1:
The non-uniform doping structure creates local variations in the channel that specifically target harmonic generation mechanisms. The first doping region with lower concentration reduces nonlinear effects at high power levels, while the second doping region maintains adequate channel control, together enabling high RF power processing with reduced harmonic distortion.
Solution Approach 2:
The patent creates a dynamically optimized channel structure where the non-uniform doping profile adapts the electrical characteristics along the channel length. This dynamic optimization allows the transistor to maintain linear operation at high RF power levels by distributing the electrical stress differently across the channel regions.
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 configuration significantly reduces harmonic power in the switching device, improving linearity and meeting stringent harmonic rejection requirements by minimizing the impact of voltage on resistance and capacitance, thereby enhancing the routing of RF signals.
Implementation Method 1
The channel region is configured to have a first doping region with a first concentration of the second type of dopant and a second doping region with a second concentration of the second type of dopant
Implementation Method 2
each comprising a cascode connection of MOSFETs with specific doping regions and PIN diodes, which model resistance and capacitance variations non-linearly with voltage, reducing harmonic power by controlling channel inversion charges and depletion regions
Data Source
AI summary
A semiconductor device includes a first doping region, a second doping region, and a channel region. The first doping region is doped with a first type of dopant. The second doping region is doped with the first type of dopant. The channel region is doped with a second type of dopant, wherein the channel region is configured to have a first region with a first concentration of the second type of dopant and a second region with a second concentration of the second type of dopant, and the second concentration is higher than the first concentration.