Hybrid-Combiner Multiband Doherty PA for Low-Loss Carrier Aggregation
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Solution Overview
Problem
Conventional multiband power amplifiers face challenges in achieving high efficiency and broadband capabilities due to the inherent narrow-band nature of Doherty PAs and the inefficiencies of existing broadband PA solutions, which result in power loss, volume, and weight issues when used in radio units with narrow-band load impedances.
Innovation Solution
A power amplifier arrangement comprising multiple narrow-band main amplifiers and wide-band auxiliary amplifiers, coupled with input and output hybrid couplers, allows for dynamic power allocation across frequency bands, eliminating the need for a 1-to-N multiplexer and enhancing efficiency through Doherty load modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If several single band PAs are paralleled with passive combiners or multiplexers to support multiband operation, then multiband capability is achieved, but significant power loss occurs
Solution Approach 1:
The patent combines multiple narrowband main PAs and wideband auxiliary PAs into a unified Doherty architecture with hybrid combiners, merging their outputs constructively for each frequency band to achieve multiband operation with high efficiency, eliminating the need for separate passive combiners per band
Solution Approach 2:
The wideband auxiliary PAs serve multiple frequency bands simultaneously, and the hybrid combiners dynamically route signals to appropriate output ports based on frequency content, enabling a single PA system to handle multiple bands efficiently without requiring dedicated PAs for each band
2Loss of energy
If a classic narrow band Doherty PA is used to achieve high efficiency, then efficiency requirement is met, but bandwidth is limited due to frequency limited quarter wave transmission lines
Solution Approach 1:
The patent segments the PA system into multiple narrowband main PAs (each optimized for specific frequency bands) and wideband auxiliary PAs, allowing each component to operate within its optimal bandwidth while collectively covering a broad frequency range with high efficiency
Solution Approach 2:
The system dynamically allocates power between narrowband main PAs and wideband auxiliary PAs based on the input signal characteristics and frequency content, enabling adaptive operation that maintains high efficiency across different frequency bands and power levels
3Adaptability or versatility
If a 1-to-N multiplexer is used to divide wideband output signal to feed N narrow-band filters, then multiband operation is supported, but extra insertion loss, volume, and weight are introduced
Solution Approach 1:
Instead of using a 1-to-N multiplexer to split a wideband signal into N separate band signals, the patent inverts the approach by using N narrowband PAs that naturally produce band-specific signals, which are then combined using hybrid combiners, eliminating the need for signal splitting and reducing insertion loss
4Adaptability or versatility
If a 1-to-N multiplexer is used to divide wideband output signal to feed N narrow-band filters, then multiband operation is supported, but volume and weight increase
Solution Approach 1:
The patent merges the functions of multiple narrowband PAs and wideband auxiliary PAs into a compact integrated system with shared components and hybrid combiners, reducing the overall volume compared to a system using separate PAs with a 1-to-N multiplexer
5Adaptability or versatility
If a 1-to-N multiplexer is used to divide wideband output signal to feed N narrow-band filters, then multiband operation is supported, but weight increases
Solution Approach 1:
The wideband auxiliary PAs and hybrid combiners serve multiple frequency bands simultaneously, eliminating the need for separate narrowband PAs and a 1-to-N multiplexer for each band, thereby reducing the overall weight of the multiband PA system
Data Source
Figure 1(a)~1(b)
Figure 2(a)
Figure 2(b)
AI summary
A power amplifier arrangement (100) for amplifying signals with multiple frequency bands (F1, F2, F3, …Fn). The power amplifier arrangement comprises multiple inputs (F1 input, F2 input, …Fn input), multiple outputs (F1 output, F2 output, …Fn output), multiple main amplifiers (Main 1, Main 2…Main n), and multiple auxiliary amplifiers (Aux 1, Aux 2…, Aux 2n). Each of the multiple main amplifiers is configured as a narrow band amplifier for amplifying a signal within one frequency band of the multiple frequency bands, each auxiliary amplifier is configured as a wideband amplifier for amplifying signals within at least two frequency bands (F1+F2, …F2+F3…) of the multiple frequency bands (F1, F2, F3, …Fn). The power amplifier arrangement further comprises one or more input hybrid couplers and one or more output hybrid couplers. An input of an auxiliary amplifier is coupled to one of the multiple inputs of the power amplifier arrangement through one or more input hybrid couplers and an output of an auxiliary amplifier is coupled to one of the multiple outputs of the power amplifier arrangement (100) through one or more output hybrid couplers such that an output signal from that auxiliary amplifier is split into different output signals within different frequency bands, and the signals within the same frequency band output from the main amplifier and auxiliary amplifiers are combined in-phase at the output of the power amplifier arrangement for providing the output signal within that frequency band.