PCB Power Amplifier Input Filtering for RF Harmonic Leakage
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Solution Overview
Problem
Current wireless communication devices generate significant radio frequency harmonics that do not comply with FCC regulations, primarily due to signal harmonics from power amplifiers, impedance mismatches, and radio frequency noise leakage through printed circuit board traces.
Innovation Solution
The implementation of an electronic circuit with a delay element and harmonic filter in the RF transmission module, which includes capacitors and chokes to attenuate signals over specific frequency bands and introduce a timing delay to dampen harmonics, while maintaining signal amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power amplifiers are used to generate RF transmissions, then wireless communication functionality is achieved, but harmonics and radio frequency noise are generated that do not comply with FCC regulations
Solution Approach 1:
A delay element is introduced as an intermediary component between the power amplifier and the output circuit. This delay element creates a timing delay that causes harmonics to be dampened while allowing the fundamental transmission frequency to pass through, thereby reducing harmful emissions without compromising wireless communication functionality
Solution Approach 2:
The invention utilizes the inherent properties of harmonics and transforms them into a beneficial effect. By introducing a delay element, the harmonics generated by the power amplifier are converted into a damping effect that actually helps reduce the harmful radio frequency noise, turning the harmful harmonics into a solution for their own suppression
2Object-generated harmful factors
If delay element is introduced to dampen harmonics, then harmonic reduction is achieved, but device complexity increases
Solution Approach 1:
The delay element changes the timing parameter of the signal passing through the circuit. By adjusting the delay time, the invention achieves harmonic dampening without requiring complex filtering circuits, thereby reducing harmonic levels with minimal increase in device 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
This solution effectively reduces harmonics around fundamental frequencies, ensuring compliance with FCC regulations by attenuating first-order harmonics and radio frequency noise, thereby minimizing unwanted emissions.
Implementation Method 1
An embodiment utilizes a delay element in the output circuit of an RF transmission to introduce a timing delay to the output signal
Implementation Method 2
The implementation of an electronic circuit with a delay element and harmonic filter in the RF transmission module, which includes capacitors and chokes to attenuate signals over specific frequency bands
Implementation Method 3
The circuit comprises: a printed circuit board 'PCB' having the power amplifier mounted on the PCB; a first electrical track in the PCB connecting to a power input terminal of the power amplifier; and a first capacitor connected to the first electrical track and a ground reference in the PCB, the first capacitor reducing transmission of radio frequency signals from the input terminal of the power amplifier
Implementation Method 4
harmonics and or noise generated due to a power and/or impedance mis-match between the output of the power amplifier and its related output circuit
Data Source
AI summary
The disclosure relates to a system and method for attenuating harmonics in output signals. In the system, an electronic circuit for reducing leakage of radio frequency signals from a power amplifier of a wireless communication device is provided. The circuit comprises: a printed circuit board ‘PCB’ having the power amplifier mounted on the PCB; a first electrical track in the PCB connecting to a power input terminal of the power amplifier; and a first capacitor connected to the first electrical track and a ground reference in the PCB, the first capacitor reducing transmission of radio frequency signals from the input terminal of the power amplifier.