Stacked RFIC Attenuator Using Coupled Lines for Linearity and Space
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Solution Overview
Problem
Existing wireless communication systems face challenges in securing both spatial efficiency and optimal linearity in signal attenuation, particularly due to the large space requirements of inductors used in power amplifiers and the need for maintaining linearity across various gain modes.
Innovation Solution
A signal attenuation device utilizing a coupled line transformer structure with transistors arranged in adjacent layers, allowing for variable impedance control through independent or interdependent switching of transistors to achieve efficient space utilization and maintain linearity, eliminating the need for separate inductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inductor is used to minimize loss in the minimum attenuation mode, then linearity is improved, but the area occupied by the device increases
Solution Approach 1:
The patent combines the inductor and capacitor into an integrated LC circuit structure that is embedded within the attenuator device. This merging eliminates the need for separate discrete inductor components while maintaining the necessary impedance transformation function, thereby reducing overall device area while preserving linearity performance
Solution Approach 2:
The patent transitions from a planar layout to a three-dimensional stacked architecture by placing the inductor and capacitor in different layers (first substrate layer and second substrate layer). This vertical arrangement allows compact integration of reactive components without increasing the footprint area, effectively resolving the space-linearity contradiction
2Adaptability or versatility
If multiple gain modes are embedded in the power amplifier, then dynamic range is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic gain adjustment through a switched-capacitor network where capacitors are selectively connected or disconnected based on the desired gain mode. This dynamic reconfiguration allows the power amplifier to switch between multiple gain modes (e.g., 0dB, -3dB, -6dB) without requiring separate amplifier circuits for each mode, thereby reducing design complexity while maintaining adaptability
Solution Approach 2:
The patent creates a universal attenuator structure that can operate across multiple gain modes using a single power amplifier circuit. The attenuator incorporates switchable capacitor networks that provide different attenuation levels, allowing one amplifier to serve multiple functions across varying signal conditions, thus reducing overall system complexity while preserving dynamic range
3Ease of operation
If the attenuator adjusts output power magnitude, then power control is improved, but signal linearity may deteriorate
Solution Approach 1:
The patent achieves power control while maintaining linearity by changing the impedance parameters of the attenuator circuit through switched capacitor networks. Instead of using simple resistive attenuation that would introduce non-linearity, the invention transforms the attenuation mechanism into an impedance transformation problem, where capacitive reactance values are dynamically adjusted to achieve different output power levels while preserving the linear relationship between input and output signals
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 efficient use of mounting space by integrating the attenuation device within the RFIC, maintaining linearity across varying input levels, and optimizing signal attenuation without significant loss or nonlinearity.
Implementation Method 1
A signal attenuation device utilizing a coupled line transformer structure with transistors arranged in adjacent layers
Data Source
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AI summary
The present disclosure relates to a 5th generation (5G) or pre-5G communication system for supporting a higher data transmission rate than a 4th generation (4G) communication system such as Long-Term Evolution (LTE). The present disclosure provides a device for variable signal attenuation equipped in a stack-up structure inside an RFIC. The device for signal attenuation comprises: a first transmission line positioned on a first layer inside the RFIC; a second transmission line positioned on a second layer, which is adjacent to the first layer, and electromagnetically coupled to the first transmission line; and a control unit. The first transmission line comprises an impedance control unit on one side. The control unit can variably control the impedance control unit.