Power Amplifier Harmonic Control via Segmented Filter Capacitor Placement
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Solution Overview
Problem
As frequency bands in mobile communication devices increase, controlling harmonics in power amplifier circuits becomes challenging due to higher harmonic frequencies and mutual coupling effects, leading to difficulties in setting suitable impedance for filter circuits.
Innovation Solution
A semiconductor device with a power amplifier circuit and dual filter circuits, where capacitors are strategically placed to attenuate harmonics, reducing the impact of wiring length variations and mutual coupling, thereby enhancing harmonic controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the frequency of transmit signal is increased to increase transmission capacity, then the transmission capacity is improved, but the controllability of harmonics deteriorates due to higher harmonic frequencies and mutual coupling effects
Solution Approach 1:
The patent divides the single filter circuit into multiple filter circuits (first filter circuit and second filter circuit) that respectively target different harmonic frequencies. The first filter circuit attenuates second-order harmonics while the second filter circuit attenuates third-order harmonics, allowing independent optimization for each harmonic frequency despite the high transmit frequency
Solution Approach 2:
The patent introduces intermediate filtering stages between the power amplifier and the antenna. These filter circuits act as intermediaries that selectively attenuate specific harmonic frequencies before they can cause interference, enabling better control over harmonics generated at high transmit frequencies
2Object-generated harmful factors
If the impedance of filter circuit is set to be low to attenuate harmonics, then the harmonic attenuation is improved, but the design difficulty increases due to mutual coupling and parasitic effects at high frequencies
Solution Approach 1:
Instead of designing a single complex filter circuit with very low impedance to handle all harmonics, the patent segments the filtering function into multiple simpler filter circuits, each targeting specific harmonic frequencies. This reduces the complexity of impedance matching and minimizes the impact of mutual coupling and parasitic effects
Solution Approach 2:
The patent changes the design approach by using multiple filter circuits with different impedance characteristics optimized for specific harmonic frequencies rather than using a single filter circuit with uniformly low impedance. This allows each filter circuit to be designed with parameters suitable for its specific frequency range, reducing design 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
The solution improves the controllability of harmonics, reducing frequency deviations and coupling effects, which enhances the efficiency and linearity of the power amplifier operation.
Implementation Method 1
The first filter circuit includes a first capacitor connected between the plurality of output terminals and a ground. The second filter circuit includes a second capacitor connected between the plurality of output terminals and a ground.
Implementation Method 2
it is difficult to set the impedance of the filter circuit to be sufficiently low. This is due to the influence of mutual coupling between elements forming the filter circuit and parasitic capacitance and parasitic resistance generated in the filter circuit.
Implementation Method 3
it is difficult to set the impedance of the filter circuit to be sufficiently low. This is due to the influence of mutual coupling between elements forming the filter circuit
Data Source
AI summary
A semiconductor device includes the following elements. A chip has a main surface substantially parallel with a plane defined by first and second directions intersecting with each other. A power amplifier amplifies an input signal and outputs an amplified signal from plural output terminals. First and second filter circuits attenuate harmonics of the amplified signal. The first filter circuit includes a first capacitor connected between the plural output terminals and a ground. The second filter circuit includes a second capacitor connected between the plural output terminals and a ground. On the main surface of the chip, the plural output terminals are disposed side by side in the first direction, and the first capacitor is disposed on a side in the first direction with respect to the plural output terminals, while the second capacitor is disposed on a side opposite the first direction with respect to the plural output terminals.