High Frequency Amplifier Balun Asymmetric Capacitance Compensation
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Solution Overview
Problem
High-frequency amplifiers often produce a high proportion of harmonic components in the output signal, reducing spectral purity, which is undesirable for accurate plasma processes due to increased parasitic capacitances in balun transformers.
Innovation Solution
Designing balun transformers with asymmetric capacitances, where the first capacitance differs from the second, to equalize impedances and compensate for parasitic components, thereby enhancing common-mode rejection and reducing harmonic impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If balancing transformers are used to convert between balanced and unbalanced transmission line systems, then impedance matching is achieved, but asymmetrical parasitic capacitances are introduced that reduce common-mode rejection ratio and spectral purity
Solution Approach 1:
The patent applies asymmetry by deliberately designing different capacitance values for the first and second capacitors connected to the balancing transformer inputs. Specifically, the first capacitor has a first capacitance value and the second capacitor has a second capacitance value that is different from the first. This asymmetrical configuration compensates for the asymmetrical parasitic capacitances inherent in the balancing transformer, thereby improving common-mode rejection ratio and reducing harmonic components in the output signal.
2Device complexity
If identical capacitances are used at the inputs of the balancing transformer, then the design is symmetrical and simple, but the impedances at the input terminals appear different due to differing phase relationships, leading to impedance mismatch
Solution Approach 1:
The patent inverts the conventional approach by not using identical capacitances despite the apparent symmetry requirement. Instead of making the capacitors equal, the invention deliberately uses different capacitance values to achieve the desired impedance matching. This inverted thinking resolves the contradiction by recognizing that the asymmetrical parasitic elements require an asymmetrical compensation strategy.
3Ease of manufacture
If symmetrical capacitance design is used in the balancing transformer, then manufacturing is simplified, but common-mode rejection ratio is reduced and harmonic components increase
Solution Approach 1:
The patent applies asymmetry by deliberately designing different capacitance values for the first and second capacitors connected to the balancing transformer inputs. Specifically, the first capacitor has a first capacitance value and the second capacitor has a second capacitance value that is different from the first. This asymmetrical configuration compensates for the asymmetrical parasitic capacitances inherent in the balancing transformer, thereby improving common-mode rejection ratio and reducing harmonic components in the output signal.
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 significantly improves the broadband compensation of parasitic components, increases common-mode rejection, and reduces undesirable effects like oscillations and uneven heating, leading to higher spectral purity and harmonic purity in the output signal.
Implementation Method 1
a first capacitance between a first input terminal of the balancing transformer and ground, and a second capacitance between a second input terminal of the balancing transformer and ground, wherein the first capacitance is designed to be different from the second capacitance. The impedances which appear at input terminals of the balancing transformer are equalized by means of the first and second capacitances.
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to a high frequency amplifier arrangement (1) comprising: a) an amplifier part (2), which has an output (100) having two output connections (101,102), b) a balun transformer (7), which has an input (105) having two input connections (106, 107) and an output (110) having two output connections (111, 112), wherein i) one output connection (101, 102) each of the amplifier part (2) is connected to an input connection (106, 107) of the balun transformer (7), ii) an output connection (112) of the balun transformer (7) is connected to ground, iii) an output connection (111) of the balun transformer (7) can be connected to a load, iv) a first capacitance (44) is provided between the one input connection (106) of the balun transformer (7) and ground, v) a second capacitance (45) is provided between the second input connection (107) of the balun transformer (7) and ground, wherein the first capacitance (44) is not equal to the second capacitance (45).