RF Amplifier Assembly LC Isolation for Shared Supply Coupling
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Solution Overview
Problem
Conventional radio frequency stages in transmitter/receiver devices suffer from cross-couplings between amplifiers due to shared power supply and ground, leading to performance degradation, especially at high frequencies, and existing solutions either reduce gain or increase cost and size.
Innovation Solution
A radio frequency assembly with amplifiers having local grounding and power supply points, connected to a common ground and power supply outside the package, and N−1 parallel LC circuits between the common power supply and local feed points to attenuate current loops, with LC circuits resonating at the amplifiers' operating frequency for optimal isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If amplifiers share common power supply and ground, then device complexity is reduced, but cross-couplings between amplifiers increase causing performance degradation
Solution Approach 1:
The patent introduces LC circuits as intermediary elements between the common power supply/ground and individual amplifiers. These LC circuits act as mediators that block harmful current loops while allowing necessary power and signal transmission, thus reducing cross-couplings without requiring completely separate power supplies for each amplifier.
Solution Approach 2:
The patent applies local quality by providing each amplifier with its own local feed point and local grounding point, rather than directly sharing common power supply and ground. This local differentiation allows each amplifier to have its own controlled impedance path, reducing interference while maintaining a compact package structure.
2Reliability
If separate power supplies and grounds are created for each amplifier, then cross-couplings are reduced, but package cost and size increase
Solution Approach 1:
The LC circuits serve as intermediary elements that provide isolation between amplifiers while maintaining connection to common power supply and ground. This approach achieves the isolation benefits of separate power supplies without the complexity and cost of fully independent power distribution networks.
Solution Approach 2:
The patent segments the power distribution network by introducing LC circuits at each amplifier's feed point and ground connection. This segmentation creates isolated current paths for each amplifier, preventing cross-couplings while still using a shared common power supply and ground infrastructure.
3Object-generated harmful factors
If RC circuits are added between power supply and common power supply, then current loops are reduced, but voltage drops increase
Solution Approach 1:
The patent changes the circuit parameters by using LC circuits instead of RC circuits. The inductive reactance of the LC circuits at operating frequencies provides current loop attenuation without the resistive voltage drops characteristic of RC circuits, thus maintaining both current loop reduction and voltage stability.
Solution Approach 2:
The LC circuits are designed to resonate at specific frequencies, creating a frequency-selective effect that blocks current loops at operating frequencies while maintaining low impedance for power delivery. This resonant behavior provides superior current loop attenuation compared to broadband RC filtering without sacrificing voltage stability.
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 configuration improves radio frequency assembly performance without increasing cost or size, achieving significant isolation between amplifiers, as demonstrated by the 20 dB isolation in the mid-band and 11 dB at the band edge.
Implementation Method 1
the LC circuit having a resonant frequency equal to the operating frequency of the amplifier
Implementation Method 2
at least N−1 parallel LC circuits disposed between the common power supply and the local feed point of an amplifier so as to attenuate the current loops between two amplifiers in series
Data Source
AI summary
The invention relates to a radio frequency assembly comprising a radio frequency circuit comprising at least one group of N≥2 amplifiers (A1, A2) disposed in series on a substrate (1), said assembly comprising a package (2) wherein the substrate (1) is disposed, each amplifier comprising a local grounding point (b1, b2, b3) and a local feed point (a1, a2, a3), said common grounding points being connected to a common ground (GND) outside the package (2), said common feed points being connected to a common power supply (VDD) outside the package, said assembly comprising at least N−1 parallel LC circuits disposed between the common power supply (VDD) and the local feed point (a2, a3) of an amplifier (A2) so as to attenuate the current loops between two amplifiers in series.