60 GHz Bandpass Filter Using Composite Resonators
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Solution Overview
Problem
Conventional bandpass filters for Wi-Fi and Bluetooth at high frequency bands, such as 60 GHz, suffer from high loss, low selectivity, limited stopband extension, and increased design complexity and cost, which hinder efficient signal processing and waveform integrity.
Innovation Solution
A wideband high frequency bandpass filter design incorporating an open-circuit resonator and a short-circuit resonator using composite right/left-handed transmission lines, with specific strip line configurations to reduce energy loss and enhance passband width, allowing for low-loss filtering at 60 GHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional transmission-line bandpass filter is used for 60 GHz wireless transmission, then the filter structure is simple and can be integrated on PCB, but the filter suffers from high loss and limited passband width
Solution Approach 1:
The patent employs composite right/left-handed transmission lines that combine conventional right-handed transmission line structures with left-handed metamaterial elements. This composite structure enables simultaneous achievement of low loss and wide passband by leveraging the complementary characteristics of both transmission line types, while maintaining PCB integrability through planar metamaterial resonator designs
2Device complexity
If conventional bandpass filter is used for 60 GHz transmission, then the design is straightforward, but the selectivity factor between passband and stopband is low
Solution Approach 1:
The patent introduces localized left-handed metamaterial resonators at specific positions within the transmission line structure. These localized elements create strong frequency-selective effects at targeted frequency points, enhancing the selectivity factor between passband and stopband without requiring complex overall filter architecture
Solution Approach 2:
The patent utilizes the unique dispersion characteristics of left-handed transmission lines, where the phase velocity and impedance parameters can be independently controlled. By adjusting the geometric parameters of the metamaterial resonators, the filter achieves sharp roll-off characteristics and improved selectivity without increasing design complexity
3Productivity
If conventional bandpass filter is used for wideband application, then the bandwidth is limited, but the stopband extension is also limited
Solution Approach 1:
The patent designs the metamaterial resonators with dynamic electromagnetic coupling characteristics that allow the filter to adaptively respond to different frequency components. The resonators exhibit frequency-dependent coupling strength, enabling wide passband for high data transfer rates while simultaneously providing extended stopband rejection through enhanced coupling at stopband frequencies
4Device complexity
If conventional bandpass filter is used for high frequency signal processing, then the structure is simple, but group hysteresis causes signal waveform distortion
Solution Approach 1:
The patent replaces the conventional mechanical transmission line structure with an electromagnetic field-based metamaterial structure. The left-handed metamaterial resonators manipulate electromagnetic waves through resonant coupling rather than physical transmission line propagation, eliminating group hysteresis effects and preserving signal waveform integrity while maintaining structural simplicity
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 filter achieves a wider passband and reduced loss, with improved selectivity and extended stopbands, enabling efficient high-frequency signal processing and reduced design complexity, suitable for 60 GHz wireless communication.
Implementation Method 1
The open-circuit resonator has a first strip line, a second strip line and a longitudinal open-circuit strip line... The short-circuit resonator has a transverse short-circuit strip line and a longitudinal short-circuit strip line
Data Source
AI summary
A wideband high frequency bandpass filter uses a metamaterial transmission line composed of an open-circuit resonator and a short-circuit resonator to realize a bandpass filter at the band of 60 GHz. The bandpass filter has an ultra-wide passband resulting from the coupling of the two resonators in the resonant modes thereof. The ultra wide passband formed by resonance coupling includes a left-handed passband and a right-handed passband. The two passbands jointly provides a passband ranging from 57.4 GHz to 63.6 GHz and having a bandwidth of 6.2 GHz. The stopbands of the bandpass filter are respectively extended downward from 57.4 GHz to the DC current and extended upward from 63.6 GHz to 109.4 GHz. The bandpass filter of the present invention can be applied to wireless transmission at the band of 60 GHz.