PD-LMBA Phase Offset Circuit for Wideband Phase Delay Accuracy
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Solution Overview
Problem
Existing pseudo-Doherty load modulated balanced amplifiers (PD-LMBAs) face challenges in achieving a satisfactory phase offset across a given frequency band, particularly due to the limitations of transmission lines in providing the required frequency-dependent phase delay.
Innovation Solution
The PD-LMBA incorporates a phase offset unit comprising shunt series circuits with impedance inverters and termination circuits, along with parallel resonance circuits, to provide a frequency-dependent phase delay that approximates the desired phase offset behavior, thereby overcoming the limitations of transmission lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmission lines are used to provide phase offset, then the structure is simple, but the frequency-dependent phase delay is insufficient to achieve satisfactory phase offset across the frequency band
Solution Approach 1:
The patent changes the electrical parameters of the phase offset unit by using impedance inverters that transform impedance values and introduce frequency-dependent phase delays. The impedance inverter circuit changes the electrical characteristics to achieve the desired phase offset behavior across the frequency band, moving beyond simple transmission line parameters.
Solution Approach 2:
The patent introduces an intermediary impedance inverter circuit between the transmission lines to achieve the required phase offset. This intermediary component transforms the impedance and introduces the necessary frequency-dependent phase delay that simple transmission lines cannot provide, acting as a mediator to resolve the phase offset issue.
2Measurement precision
If the phase offset unit uses impedance inverters and resonance circuits, then the phase delay accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent segments the phase offset unit into distinct functional components: impedance inverters, termination circuits, and parallel resonance circuits. Each segment performs a specific function - the impedance inverter transforms impedance and introduces phase delay, the termination circuit provides proper loading, and the resonance circuits enhance frequency selectivity. This segmentation allows for precise control of phase delay while managing complexity through modular design.
3Adaptability or versatility
If a regular Doherty amplifier configuration is used, then the load modulation is strong, but the phase offset control is less flexible compared to PD-LMBA
Solution Approach 1:
The patent implements dynamic phase offset control in the PD-LMBA configuration, where the phase offset unit can adaptively adjust the phase delay based on frequency and signal conditions. This dynamic capability allows the system to maintain optimal phase alignment across varying operating conditions, improving both flexibility and reliability of signal combination.
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 configuration allows for a more accurate and frequency-dependent phase delay, effectively minimizing phase offset errors across the frequency band, thus enhancing the performance of PD-LMBAs in mobile telecommunications and other applications.
Implementation Method 1
The impedance inverter is configured to transform the RF short to an RF open at the first frequency
Implementation Method 2
The at least one parallel resonance circuit is arranged in between an input and an output of the phase offset unit, wherein an impedance of the at least one parallel resonance circuit corresponds to an RF open at a second frequency
Data Source
AI summary
Example embodiments relate to pseudo-Doherty load modulated balanced amplifiers, PD-LMBAs. One example PD-LMBA is configured to operate in a given frequency band. The PD-LMBA includes a main splitter for splitting an input RF signal into a first signal and a second signal, a main amplifier for amplifying the first signal, a balanced amplifier for amplifying the second signal, and a phase offset unit. The balanced amplifier includes a splitter for splitting the second signal into a first part and a second part of the second signal, a first amplifier and a second amplifier for amplifying the first part of the second signal and the second part of the second signal, respectively, and a combiner. The phase offset unit includes at least one shunt series circuit connected to ground and at least one parallel resonance circuit arranged in between an input and an output of the phase offset unit.