Semiconductor Switch Harmonic Filtering Resonant Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor switches in mobile communication devices, such as cellular phones, face challenges in reducing harmonic components in high frequency signals, which can lead to signal interference and inefficiencies in transmission and reception.
Innovation Solution
A semiconductor switch configuration that includes specific resonant circuits and a transmission line, where the resonant circuits resonate at integer multiples of the primary frequency, and the transmission line is tuned to specific wavelengths to effectively filter out second and third harmonic components, ensuring that only the primary frequency signal is transmitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a MOS transistor switching element is used to transmit and receive high frequency signals, then transmission and reception functionality is achieved, but second and third harmonic components are generated causing signal interference
Solution Approach 1:
The patent utilizes the natural resonance characteristics of transmission lines at specific frequencies to convert the harmful harmonic components into beneficial filtering action. By designing the transmission line with specific length ratios (l2/l1 = 2N), the system exploits resonant phenomena to automatically attenuate harmonic frequencies without requiring additional active filtering components.
Solution Approach 2:
The patent changes the physical parameters of the transmission line, specifically the ratio of lengths l1 and l2, to achieve resonant conditions at harmonic frequencies. By setting l2/l1 = 2N where N is an integer, the transmission line parameters are optimized to create impedance characteristics that suppress harmonic components while maintaining signal transmission at the fundamental frequency.
2Reliability
If resonant circuits are added to filter harmonic components, then signal quality improves, but device complexity increases
Solution Approach 1:
The patent makes the transmission line serve multiple functions: it acts as both the signal transmission path and the harmonic filtering mechanism. The same transmission line structure that carries the high frequency signal also provides the resonant filtering action through its specific length ratios, eliminating the need for separate filtering circuits and reducing overall device complexity.
Solution Approach 2:
The patent merges the functions of signal transmission and harmonic filtering into a single integrated structure. The transmission line is designed with specific length ratios that combine the transmission function with the resonant filtering function, creating a unified component that performs both tasks simultaneously rather than requiring separate elements.
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
This configuration significantly reduces second and third harmonic components in high frequency signals, improving signal transmission and reception quality without affecting the primary frequency signal, thus enhancing the performance of mobile communication devices.
Implementation Method 1
a first resonant circuit having a zero impedance when resonating at a first frequency, a second resonant circuit having a zero impedance when resonating at N times the first frequency
Implementation Method 2
a transmission line having a first point connected to the second terminal, a second point connected to the first resonant circuit, and a third point connected to the second resonant circuit
Data Source
AI summary
A semiconductor switch includes a first switching element connected between a first terminal and a second terminal, a second switching element connected between the second terminal and a third terminal, a first resonant circuit having a zero impedance when resonating at a first frequency, a second resonant circuit having a zero impedance when resonating at N times the first frequency, wherein N is an integer greater than 1, and a transmission line having a first point connected to the second terminal, a second point connected to the first resonant circuit, and a third point connected to the second resonant circuit. A length of the transmission line between the first and second points corresponds to one-quarter of a wavelength corresponding to the first frequency, and a length of the transmission line between the first and third points corresponds to one-half of the wavelength corresponding to the first frequency divided by N.