High-Frequency Bypass Circuit Layout for Low Noise Figure
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Solution Overview
Problem
The existing high-frequency circuits experience degradation in noise figure due to increased switch off-capacitance when additional by-pass routes are added, leading to higher leakage of high-frequency signals and impaired transmission characteristics.
Innovation Solution
A high-frequency circuit design that includes two by-pass routes with switches connected in series, where the second by-pass route is connected to a node subsequent to the first by-pass route's switch, reducing the number of switches in parallel at the input node and minimizing switch off-capacitance, along with an impedance conversion circuit for impedance matching between the amplifier and power distributor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a distributor by-pass route is added to connect the input-side node of the amplifier and the output-side node of the power distributor, then the switching among different signal transmission states is enabled, but the number of switches connected in parallel at the input-side node increases, causing increased switch off-capacitance and degradation in noise figure
Solution Approach 1:
The by-pass route is divided into two separate segments: a first by-pass route for bypassing the amplifier and a second by-pass route for bypassing the power distributor. This segmentation allows each route to have its own switch, preventing the accumulation of multiple switches in parallel at a single node, thereby reducing total switch off-capacitance and maintaining low noise figure while still enabling versatile signal transmission state switching.
2Ease of operation
If multiple switches are connected in parallel at the input-side node to enable by-pass routing, then the signal transmission flexibility is improved, but the switch off-capacitance increases, leading to increased signal leakage and degraded transmission characteristics
Solution Approach 1:
The by-pass functionality is segmented into two independent routes with separate switches. The first switch controls the amplifier by-pass route, and the second switch controls the power distributor by-pass route. This segmentation ensures that only one switch is active at any given time, minimizing the cumulative off-capacitance effect and reducing signal leakage, thereby maintaining reliable transmission characteristics while preserving operational flexibility.
Solution Approach 2:
The first by-pass route acts as an intermediary path between the amplifier input and power distributor output. By introducing this intermediate routing option with its own dedicated switch, the system achieves signal transmission flexibility without requiring multiple switches to be simultaneously connected in parallel at the same node, thus avoiding the harmful accumulation of off-capacitance.
Data Source
AI summary
A high-frequency circuit includes an amplifier, a power distributor disposed on an output route of the amplifier, a first by-pass route that bypasses the amplifier, a second by-pass route that bypasses the power distributor, a first switch and a second switch disposed in series on the first by-pass route, and a third switch disposed in series on the second by-pass route. The first by-pass route is connected to a first node on a route connecting a signal input terminal and the amplifier and a second node on a route connecting the amplifier and the power distributor. The second by-pass route is connected to a third node between the first switch and the second switch and a fourth node on an output route of the power distributor.