PCB Supply Filter Layout for Power Amplifier RF Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication devices generate excessive signal harmonics due to power amplifier output, impedance mismatch, and radio frequency noise, which may not comply with regulatory standards like those set by the FCC, leading to potential radio frequency noise issues.
Innovation Solution
The implementation of a delay element in the RF transmission circuit, combined with harmonic filtering stages, introduces a timing delay to the output signal while maintaining amplitude, effectively dampening harmonics around fundamental frequencies, and additional capacitors are used to filter signals from the power amplifier to the battery, reducing unwanted noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power amplifier output is increased to improve transmission performance, then transmission power is improved, but harmonics and radio frequency noise increase
Solution Approach 1:
The patent extracts and removes harmful harmonics and radio frequency noise from the power amplifier output signal using filtering circuits. The filter separates the fundamental frequency signal from the harmful harmonic components, allowing the useful signal to pass while blocking the harmful frequencies, thus resolving the contradiction between maintaining high transmission power and reducing harmful emissions.
Solution Approach 2:
The patent introduces an intermediary filtering stage between the power amplifier and the antenna. This intermediary component (the filter) acts as a mediator that allows the high-power signal to pass through while selectively attenuating harmonic frequencies, thereby enabling high transmission power without directly generating harmful harmonics in the radiated signal.
2Object-generated harmful factors
If filtering circuits are added to reduce harmonics, then radio frequency noise is reduced, but device complexity increases
Solution Approach 1:
The patent applies filtering only at the specific location where it is most effective - immediately after the power amplifier output. By placing the filter locally at this critical point, the patent achieves effective harmonic reduction without requiring complex filtering throughout the entire signal path, thus minimizing the increase in device complexity while maximizing noise reduction effectiveness.
3Object-generated harmful factors
If impedance matching is improved to reduce harmonics, then radio frequency noise is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent introduces an impedance matching network as an intermediary component between the power amplifier and the filter/antenna. This matching network provides a controlled impedance transformation that reduces harmonics generated by impedance mismatches, while the standardized nature of matching network components keeps manufacturing precision requirements within normal tolerances rather than requiring extreme precision.
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 significantly reduces harmonics and radio frequency noise, ensuring compliance with regulatory standards by attenuating signals within specific frequency bands, thereby improving the overall performance and regulatory compliance of wireless communication devices.
Implementation Method 1
providing a delay element before the harmonic filter for the output signal to impart a time delay for the output signal, causing harmonics of the output signal to be reduced
Implementation Method 2
providing a harmonic filter to the output signal after the first filtering stage... attenuating signals within specific frequency bands
Implementation Method 3
additional capacitors are used to filter signals from the power amplifier to the battery, reducing unwanted noise
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The disclosure relates to a circuit (600) for reducing leakage of radio frequency signals from a power amplifier (300) of a wireless communication device. The circuit comprises a printed circuit board 'PCB' with the power amplifier (300) being mounted on the PCB. A first electrical track in the PCB is connected to a power input terminal (Vcc_Final_HB; Vcc_DVR-HB) of the power amplifier (300). A first set of capacitors is connected to the first electrical track and a ground reference in the PCB. Moreover, a ferrite bead inductor (606A) is inserted between a battery power supply terminal (VBat) and the first set of capacitors. The ferrite bead inductor (606A) and the first set of capacitors are used to reduce the transmission of radio frequency signals from the power input terminal (Vcc_Final_HB; Vcc_DVR-HB) of the power amplifier (300) to the battery power supply terminal (VBat).