Filter Layout Structure for Right-Side Band Notch Attenuation
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Solution Overview
Problem
Conventional bandpass filters do not meet attenuation requirements on the right-side band of the resonant frequency, particularly at frequencies twice the resonant frequency, due to limitations in their frequency response.
Innovation Solution
A filter circuit design featuring capacitors and inductors arranged on a substrate, with specific electrical connections and layout structures, including a third inductor on a lateral surface, allows for the creation of a notch on the right-side band of the resonant frequency, enabling adjustable notch frequency and attenuation through modification of capacitance and inductance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bandpass filter is used with standard capacitor and inductor arrangements, then the filter can be manufactured using LTCC technology, but the attenuation on the right-side band of the resonant frequency does not meet regulatory and product specification requirements
Solution Approach 1:
The filter circuit is divided into multiple functional modules: a first parallel resonant circuit (L1, C1) for the passband, a second parallel resonant circuit (L2, C2) for additional filtering, and a third parallel resonant circuit (L3, C3) specifically designed to create a notch on the right-side band. This segmentation allows each module to be optimized for its specific function, with the third module addressing the attenuation requirement on the right-side band.
Solution Approach 2:
The third parallel resonant circuit (L3, C3) is specifically configured with different component values compared to the first two circuits. The inductor L3 and capacitor C3 are designed to resonate at a frequency corresponding to the desired notch position on the right-side band, creating localized enhanced attenuation at that specific frequency region while maintaining the overall passband characteristics.
2Reliability
If the filter circuit is redesigned to add a third parallel resonant circuit for right-side band attenuation, then the attenuation performance improves, but the device complexity increases
Solution Approach 1:
Multiple parallel resonant circuits are combined in a parallel configuration within a single filter device. The first, second, and third parallel resonant circuits share common connection points to the input and output terminals, allowing them to work simultaneously without requiring separate filter devices. This merging approach achieves enhanced attenuation performance while maintaining a relatively compact and integrated structure.
Solution Approach 2:
Each parallel resonant circuit serves multiple functions: the first circuit (L1, C1) provides passband filtering, the second circuit (L2, C2) enhances filtering performance, and the third circuit (L3, C3) creates the notch on the right-side band. Additionally, all three circuits contribute to the overall impedance matching and frequency response shaping, making each component multi-functional rather than dedicated to a single purpose.
Data Source
AI summary
A filter and a layout structure of the filter are provided. The filter includes a substrate, three capacitors, and three inductors. The three capacitors and the first and second inductors are disposed on a top surface of the substrate. The third inductor is disposed on a lateral surface of the substrate. First electrodes of the first and third capacitors and a first terminal of the first inductor are connected to a first I/O terminal of the filter. A first electrode of the second capacitor, a second electrode of the third capacitor and a first terminal of the second inductor are connected to a second I/O terminal of the filter. A first terminal of the third inductor is connected to second electrodes of the first and second capacitors.