Doherty Combiner With Tunable Termination for Multi-Band Efficiency
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Solution Overview
Problem
Doherty power amplifier architectures are bandwidth limited due to their narrowband nature, making them inefficient for multi-mode/multi-band applications like 4G LTE, which requires high power-added efficiency and linearity under power back-off conditions.
Innovation Solution
A wideband tunable hybrid-based Doherty power amplifier combiner with a balun transformer circuit and a tunable impedance termination circuit, allowing for impedance matching and harmonic rejection, enabling efficient operation across multiple frequency bands without the need for multiple Doherty power amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional narrowband Doherty power combiner is used, then the power amplifier can achieve high efficiency under back-off conditions, but the bandwidth is limited and cannot support multi-mode/multi-band applications
Solution Approach 1:
The patent applies dynamics by making the termination impedance tunable rather than fixed. The termination circuit includes variable capacitors or inductors that can be adjusted to match different frequency bands, allowing the same Doherty combiner structure to adapt to multiple operating frequencies and bandwidth requirements without requiring separate amplifiers for each band
Solution Approach 2:
The patent changes the impedance parameter of the termination circuit to accommodate different frequency bands. By varying the capacitance or inductance values in the termination circuit, the combiner can maintain proper impedance matching across multiple frequency bands, thereby achieving multi-mode/multi-band operation with a single power amplifier system
2Adaptability or versatility
If multiple Doherty power amplifiers are used to cover multiple frequency bands, then bandwidth coverage is improved, but system complexity and calibration requirements increase
Solution Approach 1:
The patent achieves universality by designing a single Doherty power amplifier system that can operate across multiple frequency bands through the tunable termination circuit. The same amplifier hardware performs multiple functions by adjusting the termination impedance, eliminating the need for separate amplifiers for each frequency band and reducing overall system complexity
Solution Approach 2:
The dynamic tuning capability of the termination circuit allows one amplifier system to adapt to multiple frequency bands. By dynamically adjusting the impedance values in the termination circuit based on the desired operating band, the system achieves multi-band coverage without requiring multiple static amplifier configurations
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 solution enhances power-added efficiency and linearity under power back-off conditions, reducing system complexity and calibration requirements, while enabling efficient operation across multiple frequency bands, thus addressing the bandwidth limitations of traditional Doherty power amplifier architectures.
Implementation Method 1
A wideband tunable hybrid-based Doherty power amplifier combiner with a balun transformer circuit
Implementation Method 2
The first port and the third port are coupled by a first capacitor. The second port and the fourth port are coupled by a second capacitor
Implementation Method 3
The tunable impedance circuit can include a plurality of inductors
Data Source
AI summary
Doherty power amplifier combiner with tunable impedance termination circuit. A signal combiner can include a balun transformer circuit having a first coil and a second coil. The first coil can be implemented between a first port and a second port. The second coil can be implemented between a third port and a fourth port. The first port and the third port can be coupled by a first capacitor. The second port and fourth port can be coupled by a second capacitor. The first port can be configured to receive a first signal. The fourth port can be configured to receive a second signal. The second port can be configured to yield a combination of the first signal and the second signal. The signal combiner can include a termination circuit that couples the third port to a ground. The termination circuit can include a tunable impedance circuit.