Multilayer Band-Pass Filter Using Vertical Stub Resonators
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Solution Overview
Problem
Current band-pass filters face challenges in achieving sufficient pass attenuation on the high frequency side of their passband, particularly in higher frequency bands used in 5G communication systems, such as 10-30 GHz quasi-millimeter wavebands and 30-300 GHz millimeter wavebands.
Innovation Solution
A band-pass filter configuration that includes a first high-pass filter, a first low-pass filter, and a first stub resonator with a distributed constant line and capacitor, along with a second high-pass filter and low-pass filter, and additional stub resonators, forming attenuation poles on the high frequency side of the passband, integrated using a stack of dielectric and conductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional band-pass filter configurations are used, then the filter structure is simple, but the pass attenuation on the high frequency side of the passband is insufficient
Solution Approach 1:
The band-pass filter is segmented into multiple functional sections: a first low-pass filter, a first high-pass filter, and a first stub resonator. Each section performs a specific function (forming attenuation poles at different locations), allowing the overall pass attenuation characteristic to be improved by combining these segmented functions rather than relying on a single conventional filter configuration.
Solution Approach 2:
The first stub resonator is connected to the first path in a direction extending in the stacking direction of the stack, utilizing the vertical dimension (stacking direction) rather than only the horizontal plane. This three-dimensional configuration allows the stub resonator to form an additional attenuation pole on the high frequency side without increasing the horizontal footprint, thus improving pass attenuation while maintaining compactness.
2Area of stationary object
If the filter is miniaturized using stacked dielectric and conductor layers, then the footprint is reduced, but achieving sufficient pass attenuation at higher frequencies becomes more difficult
Solution Approach 1:
The stub resonator extends in the stacking direction (vertical dimension) of the multi-layer stack, utilizing the third dimension to achieve the required electrical length and filtering characteristics. This allows the filter to achieve sufficient pass attenuation at high frequencies (10-30 GHz quasi-millimeter wavebands and 30-300 GHz millimeter wavebands) without increasing the horizontal footprint, enabling miniaturization while maintaining high-frequency performance.
Solution Approach 2:
The filter components (input/output ports, low-pass filter, high-pass filter, stub resonator) are integrated into a compact multi-layer stack structure where dielectric layers and conductor layers are nested together. This nesting approach allows all necessary components to be housed in a small footprint while maintaining the electrical performance required for high-frequency operation with adequate pass attenuation.
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 proposed configuration significantly increases pass attenuation on the high frequency side of the passband, enhancing the filter's performance in higher frequency bands while allowing for miniaturization and maintaining desired characteristics.
Implementation Method 1
a first stub resonator including a first distributed constant line... each of the first low-pass filter and the first stub resonator may form an attenuation pole on a high frequency side of the passband
Implementation Method 2
a first stub resonator including a first distributed constant line... the first stub resonator may further include a second capacitor provided between the first distributed constant line and the ground
Implementation Method 3
a first high-pass filter, a first low-pass filter... each of the first high-pass filter and the first low-pass filter includes at least one first inductor and at least one first capacitor
Data Source
AI summary
A band-pass filter includes a first input/output port, a second input/output port, a first high-pass filter, a first low-pass filter, and a first stub resonator. The first stub resonator includes a first distributed constant line. The first low-pass filter is provided between the first input/output port and the first high-pass filter in the circuit configuration. The first distributed constant line has a first end connected to a first path connecting the first input/output port and the first low-pass filter, and a second end closest to a ground in the circuit configuration.