RF Power Combiner Circuit With Phase Shifting for Tx/Rx Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio-frequency (RF) circuits face challenges in achieving highly efficient power combining while maintaining improved isolation between transmission and reception signals, particularly under load fluctuations.
Innovation Solution
The RF circuit incorporates a splitter and combiner circuit with phase-shifting circuits configured to achieve a 180° phase difference in reflection phases between output ends, along with filters tuned to specific bands, ensuring efficient power combining and enhanced isolation between transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional power coupler composed of resistor, inductor, and inductor is used for power combining, then the circuit structure is simple, but the power combining efficiency is low due to power loss in the resistor
Solution Approach 1:
The patent changes the electrical parameters of the power combining circuit by using capacitors with specific capacitance values and inductors with specific inductance values to achieve resonance at the operating frequency. This transforms the power combining mechanism from resistive to reactive, eliminating power loss while maintaining circuit functionality. The parameter optimization includes selecting capacitor ratios and inductor values that satisfy both power combining efficiency and impedance matching requirements.
2Productivity
If transmission and reception signals are simultaneously transmitted, then communication efficiency is improved, but isolation between transmission and reception deteriorates causing signal leakage
Solution Approach 1:
The patent segments the signal paths by introducing separate transmission and reception signal paths with dedicated phase-shifting circuits. The transmission signal path includes a first phase-shifting circuit while the reception signal path includes a second phase-shifting circuit, allowing independent control of each path's phase characteristics. This segmentation enables simultaneous transmission and reception by directing signals through different routed paths with appropriate phase relationships.
Solution Approach 2:
The patent introduces phase-shifting circuits as intermediary components between the power amplifiers and the antenna. These intermediary circuits actively adjust the phase of signals to create destructive interference for leakage signals while preserving the desired transmission and reception signals. The phase-shifting circuits act as mediators that manipulate signal phases to achieve both simultaneous operation and isolation.
3Object-affected harmful factors
If phase-shifting circuits are added to achieve 180° phase difference for isolation improvement, then signal isolation is enhanced, but device complexity increases
Solution Approach 1:
The patent merges the phase-shifting function with the existing power combining circuitry by integrating phase-shifting circuits into the signal paths of the balanced amplifier configuration. Rather than adding completely separate phase-shifting modules, the design combines phase adjustment capabilities with the power combining network, sharing common components and signal paths where possible. This merging approach achieves the required 180° phase difference while minimizing additional component count.
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 provides an RF circuit with highly efficient power combining and improved isolation between transmission and reception signals, effectively suppressing signal leakage and enhancing overall performance.
Implementation Method 1
a first phase-shifting circuit connected between the third output end and the fourth input end; a second phase-shifting circuit that is connected between the fourth output end and the fifth input end, and is configured such that a passband phase of the signal in the transmission band of the first band becomes relatively −90° with respect to the first phase-shifting circuit
Implementation Method 2
the first phase-shifting circuit and the second phase-shifting circuit are configured such that a difference between a first reflection phase in the reception band of the second band upon viewing the fifth output end from the third output end and a second reflection phase in the reception band of the second band upon viewing the fifth output end from the fourth output end becomes 180°
Implementation Method 3
a first filter that is connected between the fifth output end and the first antenna terminal or between the first phase-shifting circuit and the fourth input end, and has a passband containing the transmission band of the first band; and a second filter that is connected to a path connecting the first antenna terminal and the first filter, and has a passband containing a reception band of a second band that can be transmitted simultaneously with the first band
Implementation Method 4
a combiner circuit that has a fourth input end, a fifth input end, and a fifth output end, and is configured to output, from the fifth output end, an output signal in the first band generated by combining in phase a third sub-band signal in the first band input from the fourth input end and a fourth sub-band signal in the first band input from the fifth input end
Data Source
AI summary
A radio-frequency circuit includes: a power amplifier to which a first signal is input; a power amplifier to which a second signal that is +90° with respect to the first signal is input; a combiner circuit that combines in phase a third signal in band A input from a fourth input end and a fourth signal in band A input from a fifth input end; a phase-shifting circuit connected to a third output end of the power amplifier; a phase-shifting circuit that is connected to a fourth output end of the power amplifier and sets a passband phase of a signal in band A to −90° with respect to the phase-shifting circuit; a filter that has a passband containing a transmission band of band A; and a filter that has a passband containing a reception band of band B that can be transmitted simultaneously with band A.