Wideband Doherty Amplifier Layout With Shortened Phase Lines
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Solution Overview
Problem
Doherty amplifiers require additional physical space due to their configuration, which is a challenge for applications with dimensional constraints, such as standard-sized racks in broadcasting systems, leading to inefficiencies in power consumption and installation density.
Innovation Solution
The method involves reducing the physical length of phase-shifting lines in Doherty amplifiers while maintaining their electric length, achieved by adding capacitors in series or parallel to transmission lines, allowing for a more compact design that fits within standardized rack dimensions without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Doherty configuration is used to increase amplification efficiency, then energy efficiency is improved, but physical space occupation increases
Solution Approach 1:
The patent changes the electrical parameters of transmission lines by adding capacitors in series or parallel to modify the electrical length while reducing physical length. This allows maintaining the required phase shifting function (90 degrees at carrier frequency) with shorter physical dimensions, thereby reducing the overall amplifier footprint while preserving the Doherty configuration's efficiency benefits
Solution Approach 2:
The patent transforms the problem from a two-dimensional planar layout constraint to a three-dimensional solution by using vertical stacking of transmission line elements and capacitors. This allows the amplifier to fit within standardized rack dimensions (19-inch width) by utilizing vertical space and layered PCB structures, effectively reducing the plan width occupation
2Adaptability or versatility
If phase-shifting lines are designed for wideband operation, then frequency bandwidth is improved, but plan width increases
Solution Approach 1:
The patent modifies the electrical characteristics of transmission lines by introducing capacitive elements that alter the phase velocity and electrical length. This allows the same physical line to provide the required 90-degree phase shift across a wider frequency bandwidth while maintaining a compact physical footprint, thus achieving wideband operation without increasing plan width
3Ease of manufacture
If standardized rack dimensions are used to optimize installation, then ease of installation is improved, but amplifier power output is reduced
Solution Approach 1:
The patent enables high-power Doherty amplifiers to fit within standardized 19-inch rack dimensions by utilizing vertical stacking of transmission line elements and capacitors on multi-layer PCBs. This three-dimensional arrangement preserves the required electrical performance and power handling capability while conforming to standard rack widths, thus maintaining both ease of installation and high power output
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 enables a widerband Doherty amplifier with reduced plan width, allowing for higher output power in the same space, thereby optimizing space usage and reducing power consumption while maintaining efficiency.
Implementation Method 1
adding capacitors in series or parallel to transmission lines
Data Source
AI summary
A method for making a wideband Doherty amplifier with reduced plan width, adapted to transport a radio-frequency signal at a frequency value comprised within a frequency range defined between a minimum frequency value and a maximum frequency value, the amplifier including: a signal source adapted to generate an input signal; a hybrid coupler or a splitter network adapted to receive the input signal and divide it into first and second output signals phase-shifted by 90°; a carrier amplifier adapted to receive as input the first output signal; a peak amplifier adapted to receive as input the second output signal; an output network arranged between the carrier and peak amplifiers and a delivery node adapted to be connected to a load, the output network including a recombination node adapted to receive the signals output by the carrier amplifier and the peak amplifier, and a transmission line implemented as a printed circuit track applied to an insulating substrate, wherein capacitors are inserted on the track which are adapted to compensate for the non-ideality characteristics of the semiconductor used for making the line.