Tournament Power Amplifier Layout for Wide-Band Distortion Reduction
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Solution Overview
Problem
Existing microwave power amplifiers face challenges in achieving lower distortion while increasing the offset frequency, particularly in the order of 100 MHz, and require larger package sizes to accommodate difference frequency short circuits, which is problematic for satellite and mobile communication systems.
Innovation Solution
A power amplifier design featuring a tournament circuit with multiple transmission lines and difference frequency short circuits, each comprising an inductor and capacitor connected in series, where resonant frequencies decrease with distance from the amplifiers, and specific impedance matching is achieved through inductive reactance and capacitive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single λ/4 wavelength line is connected to multiple capacitors in parallel, then the circuit structure is simple, but the resonant frequency is single and cannot achieve low distortion characteristics over a wide band difference frequency range
Solution Approach 1:
The single bias circuit is segmented into multiple independent bias circuits, each with its own λ/4 wavelength line and capacitor. This segmentation allows each circuit to resonate at a specific difference frequency, collectively covering a wide frequency range and achieving low distortion characteristics across the entire band while maintaining structural simplicity.
2Reliability
If multiple difference frequency short circuits with different resonant frequencies are directly connected to the drain terminal, then distortion characteristics improve, but the package size must be increased to accommodate all inductors and capacitors
Solution Approach 1:
Multiple bias circuits are merged into a single integrated structure within the package. The λ/4 wavelength lines and capacitors are arranged in a compact configuration that allows all necessary components for multiple resonant frequencies to coexist in a small area, achieving both low distortion characteristics and compact package size.
Solution Approach 2:
The layout transitions from a planar arrangement to a three-dimensional configuration, utilizing vertical stacking and layered routing of transmission lines and components. This dimensional change allows efficient space utilization, accommodating multiple inductors and capacitors for different resonant frequencies without increasing the package footprint.
3Manufacturing precision
If an inductor with electrical length of λ/4 is used for output impedance matching, then matching at a specific frequency is achieved, but the output impedance cannot be altered on real axes and wide-band matching is difficult
Solution Approach 1:
The output matching circuit uses variable inductors with adjustable electrical lengths instead of fixed λ/4 inductors. This dynamic configuration allows the inductance values to be adjusted to alter the output impedance on real axes, achieving favorable impedance matching across a wide frequency band by adapting to different operating conditions.
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 design enables wide-band linearity without increasing the package size, reducing distortion components over a wide frequency range, and maintaining uniform impedance across amplifiers, thus enhancing transmission capacity.
Implementation Method 1
a plurality of difference frequency short circuits each including an inductor and a capacitor connected in series to each other
Implementation Method 2
difference frequency short circuits connected to a plurality of nodes in a stage closest to the amplifiers of the tournament circuit among the plurality of difference frequency short circuits include inductive reactance that resonates with impedance seen from the nodes toward the amplifiers at an operating frequency
Data Source
AI summary
A power amplifier includes: a plurality of amplifiers; a tournament circuit including a plurality of transmission lines arranged in a tournament form and connected to the plurality of amplifiers; and a plurality of difference frequency short circuits each including an inductor and a capacitor connected in series to each other, wherein resonant frequencies of the plurality of difference frequency short circuits become smaller as the difference frequency short circuits are farther from the plurality of amplifiers, and difference frequency short circuits connected to a plurality of nodes in a stage closest to the amplifiers of the tournament circuit among the plurality of difference frequency short circuits include inductive reactance that resonates with impedance seen from the nodes toward the amplifiers at an operating frequency and have different resonant frequencies.