LC Lattice Impedance Inversion for Wideband Doherty Amplifiers
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Solution Overview
Problem
Conventional Doherty power amplifiers face significant bandwidth limitations due to the impedance inverter, which restricts their performance and efficiency in modern communication systems, including 5G and non-terrestrial networks, necessitating multiple band power amplifiers and increasing manufacturing costs.
Innovation Solution
Implementing a Doherty power amplifier with an inductor-capacitor (LC) lattice structure as an impedance inverter, which enhances broadband operation and maintains high efficiency and linearity, allowing a single amplifier to support multiple frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional impedance inverter is used in Doherty power amplifier, then the amplifier can be manufactured with standard design, but the bandwidth is limited and multiple band power amplifiers are required
Solution Approach 1:
The patent transforms the conventional quarter-wavelength transmission line impedance inverter into a lumped element LC lattice network. This parameter change from distributed to lumped elements enables broadband operation by eliminating the frequency-dependent constraints of transmission line length, allowing the amplifier to operate across multiple frequency bands while maintaining impedance inversion functionality.
Solution Approach 2:
The impedance inverter is segmented into discrete inductor and capacitor components arranged in a lattice configuration. This segmentation allows independent optimization of each component's value to achieve broadband matching and enables the amplifier to handle multiple frequency bands simultaneously, resolving the bandwidth limitation of conventional designs.
2Adaptability or versatility
If multiple band power amplifiers are used to support different frequency bands, then bandwidth coverage is improved, but manufacturing cost and device size increase
Solution Approach 1:
The LC lattice impedance inverter is designed to function across multiple frequency bands simultaneously, making a single Doherty power amplifier universal for broadband applications. This eliminates the need for multiple separate amplifiers for different bands, reducing manufacturing costs and device size while maintaining support for various frequency ranges including 5G bands.
3Adaptability or versatility
If multiple band power amplifiers are used to support different frequency bands, then bandwidth coverage is improved, but device size increases
Solution Approach 1:
The single Doherty power amplifier with LC lattice impedance inverter provides multi-band functionality, eliminating the need for multiple separate amplifier modules. This consolidation significantly reduces the overall device volume while maintaining the capability to operate across multiple frequency bands including 5G NR bands, thereby resolving the space constraint.
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 LC lattice structure enables wideband operation, supporting two or more frequency bands with high efficiency and linearity, reducing the need for multiple power amplifiers and minimizing the amplifier's size, thus lowering manufacturing and integration costs.
Implementation Method 1
an impedance inverter including a first series inductor having a first end electrically connected to the inverted carrier output and a second end electrically connected to the inverted peaking output
Implementation Method 2
the first series inductor is electromagnetically coupled to the second series inductor to provide a mutual inductance
Data Source
AI summary
Doherty power amplifiers with an inductor-capacitor (LC) lattice for impedance inversion are disclosed. In certain embodiments, a Doherty power amplifier includes a carrier amplifier, a peaking amplifier, and an LC lattice that serves as an impedance inverter for combining a differential carrier signal from the carrier amplifier with a differential peaking signal from the peaking amplifier. The LC lattice can include series inductors and cross capacitors connected to form a lattice, or series capacitors and cross inductors connected to form the lattice.