Dual-Band Wi-Fi Diplexer With Tunable Harmonic Suppression
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Solution Overview
Problem
Existing diplexers face challenges in achieving a balanced trade-off between insertion loss, layout size, manufacturing cost, and stopband suppression for dual-band Wi-Fi applications.
Innovation Solution
A diplexer design incorporating tunable resonant circuits and resonant units with adjustable capacitors and inductors, utilizing silicon on insulator technology and CMOS processes, to filter out specific harmonics of RF signals, thereby reducing electromagnetic interference and minimizing layout size while maintaining low insertion loss and superior stopband suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional diplexer designs (LTCC, IPD, thin film) are used, then manufacturing is feasible with existing processes, but insertion loss is high and stopband suppression is insufficient
Solution Approach 1:
The diplexer is divided into two independent filter circuits (first filter circuit for first RF signal, second filter circuit for second RF signal), each with dedicated resonant circuits. This segmentation allows independent optimization of each signal path, reducing interference and insertion loss while improving stopband suppression through targeted harmonic filtering.
Solution Approach 2:
The patent employs tunable resonant circuits with adjustable capacitors and inductors that can be configured to different values. This dynamic adjustability enables optimization of resonance frequencies and Q-factors to minimize insertion loss at operating frequencies while maximizing stopband suppression at harmonic frequencies.
2Reliability
If more filter circuits and resonant elements are added to improve stopband suppression, then harmonic filtering improves, but layout size increases
Solution Approach 1:
Multiple resonant circuits are merged into a compact shared architecture where the first and second filter circuits share common substrates and interconnection structures. This merging approach maintains superior stopband suppression through multiple resonant elements while minimizing layout size through shared resources and integrated design.
Solution Approach 2:
The patent utilizes multi-layer substrate structures (silicon on insulator technology) to arrange resonant elements in three-dimensional space rather than solely in planar layout. This dimensional transition allows compact integration of multiple filter circuits and resonant elements, achieving high stopband suppression without proportional increases in layout area.
3Area of stationary object
If compact design is implemented to reduce layout size, then area is minimized, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses adjustable capacitor and inductor parameters in the resonant circuits that can be optimized during manufacturing. By carefully selecting and tuning these parameters, the design achieves compact layout with standard manufacturing processes, avoiding the need for complex or expensive specialized fabrication techniques.
4Object-generated harmful factors
If harmonic filtering is enhanced to reduce electromagnetic interference, then signal quality improves, but insertion loss increases
Solution Approach 1:
The patent converts the potentially harmful harmonic frequencies into beneficial filtering opportunities by designing resonant circuits with transmission zeros specifically positioned at harmonic frequencies. The resonant circuits are tuned to create notches at 2nd, 3rd, and 4th harmonics, transforming what would be interference sources into controlled filtering points that reduce EMI without affecting fundamental signal transmission.
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 diplexer achieves low insertion loss, minimal layout size, reduced cost, and enhanced stopband suppression by effectively filtering out harmonics, improving signal quality and reducing electromagnetic interference.
Implementation Method 1
The first filter circuit includes a first tunable resonant circuit for tuning a first transmission zero corresponding to a first frequency multiplication of the first RF signal
Data Source
AI summary
A diplexer includes a first filter circuit, and a second filter circuit. The first filter circuit is coupled to a first port for providing a first signal path for a first radio frequency (RF) signal. The second filter circuit is coupled to the first port for providing a second signal path for a second RF signal. The first filter circuit includes a first tunable resonant circuit for tuning a first transmission zero corresponding to a first frequency multiplication of the first RF signal. The second filter circuit includes a second tunable resonant circuit for tuning a first transmission zero corresponding to a first frequency multiplication of the second RF signal. The first frequency multiplication of the first RF signal corresponding to the first filter circuit is a fourth harmonic of the first RF signal.