RF Power Combiner With Printed Transformers for CMOS Output Power
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Solution Overview
Problem
Traditional power amplifiers face challenges in delivering high output power efficiently due to voltage scaling in nanoscale technology, requiring multiple transistors and power combiners, which are difficult to manufacture in low-cost nanoscale CMOS processes, and suffer from power loss and leakage issues due to high-power-rated switches and antenna mismatch.
Innovation Solution
A low-cost, high-efficiency power combiner using nanoscale CMOS technology with multiple transformers and micro power amplifiers connected in series, combined with a series resonant capacitor to resonate out leakage inductance, and a matching circuit to compensate for antenna mismatch, enabling efficient power transfer across multiple frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple micro power amplifiers are used to deliver high output power in nanoscale CMOS, then the output power requirement is met, but the manufacturing difficulty and cost increase significantly
Solution Approach 1:
The power amplifier is divided into multiple micro power amplifiers (MPAs) operating in parallel, each handling a portion of the total output power. This segmentation allows nanoscale CMOS transistors with limited individual power capability to collectively deliver high output power while remaining manufacturable in standard low-cost nanoscale CMOS processes
Solution Approach 2:
Multiple micro power amplifiers are combined through a power combiner network to achieve the required total output power. The merging of multiple low-power signals into a single high-power output enables the system to meet power requirements without requiring any single transistor to exceed nanoscale CMOS capabilities
2Adaptability or versatility
If traditional high-power-rated switches are used for frequency band switching, then multiple frequency bands can be covered, but power loss increases by 0.5-1 dB
Solution Approach 1:
The traditional high-power-rated switches are completely removed from the frequency band switching architecture. Instead, the patent uses a single power amplifier with a power combiner network that can operate across multiple frequency bands without requiring high-power switches, thereby eliminating the 0.5-1 dB power loss associated with switch resistance
Solution Approach 2:
A single power amplifier design is made universal across multiple frequency bands through the use of a power combiner network with multiple inputs. This allows the same amplifier to serve multiple frequency bands (e.g., GSM 850, GSM 900, DCS 1800, PCS 1900) without requiring separate amplifiers or high-power switches for band selection
3Adaptability or versatility
If high-power-rated switches are used for band selection, then multiple frequency bands can be selected, but leakage increases and dynamic range decreases
Solution Approach 1:
High-power-rated switches are completely extracted from the architecture, eliminating the leakage and finite isolation problems they cause. The power combiner network inherently provides better isolation between frequency bands without requiring additional switching components that would introduce leakage
4Reliability
If antenna mismatch occurs, then reflected power increases and emitted power decreases, but adding a controllable matching circuit increases device complexity
Solution Approach 1:
A controllable matching circuit is implemented that can dynamically adjust its parameters to compensate for antenna mismatch conditions. The matching circuit responds to varying load conditions and maintains optimal power transfer efficiency across different operating conditions, thereby improving reliability without permanently increasing complexity
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 enables a high-output, low-loss RF power amplifier with improved efficiency and reduced leakage, capable of covering multiple frequency bands with a single RF power amplifier, reducing manufacturing costs and enhancing dynamic range.
Implementation Method 1
combined with a series resonant capacitor to resonate out leakage inductance
Implementation Method 2
A low-cost, high-efficiency power combiner using nanoscale CMOS technology with multiple transformers and micro power amplifiers connected in series
Data Source
AI summary
Methods to implement low cost, high efficiency, low loss power combiner with novel matching circuits are disclosed. A narrow band power combiner enables a high power and high efficiency radio frequency power amplifier to be realized using multiple low voltage CMOS transistors or micro power amplifiers. The power combiner may be printed on a package substrate and realized either using single layer substrate through edge coupling or multiple layers substrate through broadside coupling. The micro power amplifiers may be fabricated using low voltage CMOS technology and electrical connections between the outputs from the micro power amplifiers and the power combiner may be provided through stud bumps in a flip chip technology. With the tunable matching circuits, the present invention allows the narrow band power combiner to be tuned to different frequencies.