CMOS Power Amplifier Matching Network Without TX Switch Loss
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Solution Overview
Problem
In 5G millimeter-wave TDD systems, the use of a TX switch degrades power amplifier performance by wasting output power, and existing solutions for impedance matching are inefficient, particularly in the 26.5-30 GHz frequency range.
Innovation Solution
A wide band matching network is introduced, comprising a power amplifier transistor connected to an output network with a series capacitor and an on-chip transformer that acts as a second-order filter, eliminating the need for a TX switch by using a series capacitor to provide impedance matching and isolating the receiver when the power amplifier is off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a TX switch is used to isolate the receiver when the power amplifier is off, then the receiver is protected from signal interference, but the power amplifier performance is degraded due to insertion loss
Solution Approach 1:
The patent removes the TX switch from the power amplifier output path and replaces it with a series capacitor. This extraction of the switching component eliminates the insertion loss while maintaining receiver isolation through the capacitor's high impedance when the receiver is active.
Solution Approach 2:
The series capacitor acts as an intermediary element between the power amplifier and receiver. It provides high impedance isolation when the receiver is on, protecting the receiver without requiring a TX switch that would degrade power amplifier performance.
2Adaptability or versatility
If a TX switch is used to enable TDD operation, then transmitter and receiver can operate individually, but the switch degrades power amplifier performance
Solution Approach 1:
The TX switch is completely removed from the system. Instead, the series capacitor provides the necessary isolation for TDD operation without the energy losses associated with mechanical or electronic switches.
Solution Approach 2:
The patent changes the impedance parameter of the output network by using a series capacitor whose impedance characteristics (high when receiver is on) enable TDD operation without the performance degradation of traditional switches.
3Manufacturing precision
If traditional impedance matching networks are used in the 26.5-30 GHz frequency range, then impedance matching can be achieved, but the matching is inefficient and narrowband
Solution Approach 1:
The series capacitor serves multiple functions simultaneously: it provides impedance matching across the wide 26.5-30 GHz band, enables TDD operation through its high impedance isolation, and eliminates the need for a TX switch. This multi-functionality achieves both accurate matching and high efficiency.
Solution Approach 2:
The patent optimizes the capacitor's electrical parameters (capacitance value, series resistance) to achieve wideband impedance matching in the 26.5-30 GHz range, improving both matching accuracy and efficiency compared to traditional narrowband solutions.
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 solution enhances power amplifier performance by reducing insertion loss and conserving output power, while maintaining high impedance to prevent signal interference when the receiver is on, thus optimizing power usage and signal integrity in 5G mm-wave systems.
Implementation Method 1
A wide band matching network for power amplifier impedance matching
Implementation Method 2
an on-chip transformer connected to the capacitor in series
Implementation Method 3
a series capacitor; the transformer and the capacitor act as a second order filter
Implementation Method 4
A wide band matching network for power amplifier impedance matching, the wide band matching network comprising: a power amplifier transistor connected to an output network
Data Source
AI summary
A wide band matching network for power amplifier impedance matching, the wide band matching network comprising: a power amplifier transistor connected to an output network; the output network including: a series capacitor; an on-chip transformer connected to the capacitor in series, wherein the transformer and the capacitor act as a second order filter; and a port connected to the capacitor and a receiver switch.