Self-Matching Band-Pass Filter with Variable Trace Width Resonators
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Solution Overview
Problem
Conventional satellite communication systems face inefficiencies in RF signal transmission due to the lack of impedance matching between the band-pass filter and the rear-stage circuit, leading to increased signal loss and noise interference.
Innovation Solution
A band-pass filter design with resonators of varying trace widths to match the output impedance with the input impedance of the rear-stage circuit, reducing the need for external matching circuits and minimizing signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional band-pass filter with fixed trace width resonators is used, then the filter structure is simple and easy to manufacture, but the output impedance cannot be matched with the input impedance of the rear-stage circuit, leading to increased signal loss
Solution Approach 1:
The patent applies local quality by varying the trace width of resonators at different positions within the band-pass filter. Specifically, the resonators have different trace widths (W1, W2, W3) at different sections to create different impedance characteristics at different locations. This local variation in geometric parameters enables impedance transformation from the filter output to match the rear-stage circuit input impedance, thereby reducing signal loss without requiring an external matching circuit.
2Reliability
If an external matching circuit is added between the band-pass filter and rear-stage circuit, then impedance matching can be achieved, but the device complexity increases and transmission line effects are not minimized
Solution Approach 1:
The patent merges the impedance matching function with the band-pass filter structure itself. By integrating variable trace width resonators directly into the filter design, the matching circuit functionality is combined with the filtering functionality. This eliminates the need for a separate external matching circuit, reduces overall device complexity, and minimizes transmission line effects by removing additional connection interfaces.
Solution Approach 2:
The band-pass filter performs self-impedance-matching through its internal resonator design with varying trace widths. The filter structure automatically provides the necessary impedance transformation from its output to match the rear-stage circuit input, without requiring external assistance. This self-service capability simplifies the overall system design and reduces the number of external components needed.
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 self-matching band-pass filter design enhances signal transmission by reducing noise and signal loss, improving the noise characteristics and conversion gain of the mixer, thereby optimizing the performance of the frequency down converter.
Implementation Method 1
a plurality of resonators placed between the input port and the output port, for performing band pass filtering on the radio-frequency signal to generate the filtered signal
Implementation Method 2
The plurality of resonators comprise at least two different trace widths for matching the output impedance of the band-pass filter with the input impedance of a rear-stage circuit coupled to the output port
Data Source
AI summary
A band-pass filter includes an input port, an output port, and a plurality of resonators. The input port is utilized for receiving a radio frequency signal. The output port is utilized for outputting a filtered signal. The plurality of resonators are placed between the input port and the output port, and are utilized for band-pass filtering the radio frequency signal for generating the filtered signal, wherein the plurality of resonators comprise at least two different trace widths for matching the output impedance of the band-pass filter with the input impedance of a rear-stage circuit coupled to the output port.