RF Module LNA Parasitic Capacitance Reduction
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Solution Overview
Problem
Conventional radio frequency modules experience increased noise figure due to parasitic capacitance between inductors and low noise amplifiers, resulting from long wiring lengths between these components.
Innovation Solution
A radio frequency module design that includes an input matching circuit with an inductor adjacent to the low noise amplifier, reducing wiring length and minimizing parasitic capacitance by placing the reception filter directly on the low noise amplifier and using a configuration that includes at least one inductor in the input matching circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the inductor is disposed on the mounting board and electrically connected to the low noise amplifier disposed on the reception filter, then the module structure is achieved, but the wiring length becomes long causing parasitic capacitance to occur
Solution Approach 1:
The inductor is integrated directly onto the low noise amplifier substrate, merging two previously separate components (inductor on mounting board, LNA on reception filter) into a combined structure. This eliminates the long wiring path through the mounting board and reduces parasitic capacitance between the inductor and LNA.
Solution Approach 2:
The patent transitions from a planar arrangement where both components are on the mounting board to a three-dimensional arrangement where the inductor is placed on the LNA substrate itself. This spatial reorganization in another dimension (on the LNA package rather than on the PCB) dramatically shortens the electrical connection path.
2Ease of manufacture
If the inductor is disposed on the mounting board and connected via wire bonding, then the components can be separately manufactured, but the wiring length increases making parasitic capacitance more likely
Solution Approach 1:
The inductor and LNA are combined into a single integrated structure on the LNA substrate, eliminating the need for wire bonding through the mounting board. This integration maintains manufacturability while dramatically reducing the connection length and associated parasitic effects that degrade noise figure.
3Device complexity
If the reception filter is disposed on the mounting board, then the low noise amplifier can be disposed on the reception filter, but the wiring length between the inductor and low noise amplifier becomes long
Solution Approach 1:
The patent moves the inductor from the mounting board plane to the LNA substrate plane, creating a vertical integration architecture. This dimensional change allows the inductor to be positioned immediately adjacent to the LNA input terminal, reducing the wiring length to minimal traces on the LNA substrate rather than long paths through the mounting board.
Data Source
AI summary
A radio frequency module includes a mounting board, a low noise amplifier, a reception filter, and an input matching circuit. The low noise amplifier is mounted on the mounting board. The reception filter is connected to the low noise amplifier. The input matching circuit is provided on a signal path between the reception filter and the low noise amplifier. The input matching circuit includes at least one inductor. The reception filter is disposed on the low noise amplifier. The at least one inductor included in the input matching circuit is adjacent to the low noise amplifier such that no other circuit element is present between the low noise amplifier and the at least one inductor.