Biased NLTL Comb Generator for Wideband Low-Noise Harmonics
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Solution Overview
Problem
Conventional comb generators have limitations in accepting input signals over a narrow range of frequencies and power levels, leading to restricted picket spacing and frequency span, and introduce substantial phase noise due to the use of step recovery diodes.
Innovation Solution
The proposed comb generators utilize a nonlinear transmission line (NLTL) with pulse forming bias networks to establish nonlinearity, comprising Schottky diodes and transmission line sections, allowing for broader frequency range acceptance and improved phase noise characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If step recovery diodes are used to generate harmonics, then impulse-like electrical signals can be produced, but the frequency range and power level acceptance is limited
Solution Approach 1:
The patent changes the operating parameters of the nonlinear transmission line by using pulse forming bias networks to dynamically adjust the bias voltage based on the input signal characteristics. This allows the system to adapt to a broader range of input frequencies and power levels while maintaining harmonic generation performance.
Solution Approach 2:
The bias networks are configured to dynamically establish nonlinearity in the NLTL based on the input periodic signal characteristics. This dynamic adjustment enables the system to adapt to varying input conditions rather than requiring fixed operating parameters.
2Reliability
If step recovery diodes are used to produce impulse-like signals, then harmonics can be generated, but substantial phase noise is introduced
Solution Approach 1:
The patent extracts the harmful phase noise characteristic from the conventional SRD approach by replacing the SRD with a biased NLTL configuration. The bias networks are specifically designed to establish nonlinearity without introducing the substantial phase noise that characterizes SRD-based generators.
Solution Approach 2:
The patent uses readily available Schottky diodes in a configured NLTL structure rather than specialized SRDs. This approach achieves comparable or superior performance with common components that do not introduce the same phase noise problems.
3Adaptability or versatility
If conventional comb generators are used, then harmonics can be produced, but picket spacing selection is difficult due to limited output spacing
Solution Approach 1:
The bias networks dynamically adjust the nonlinearity of the NLTL based on the input signal, enabling flexible control over the generated harmonics and their spacing. This allows users to select different pickets from the comb more easily by adjusting the bias conditions.
Solution Approach 2:
The NLTL-based comb generator is designed to provide multiple frequency components with adjustable spacing, making it a universal tool that can serve different frequency selection needs without requiring multiple specialized devices.
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 NLTL-based comb generators can accept input signals over a broader frequency range and operate with varying power levels, reducing phase noise and enhancing the selection of specific frequency components, thereby improving the generation of high-frequency signals.
Implementation Method 1
the first PFBN is configured to at least partially establish a nonlinearity of the at least two nonlinear elements based on the input periodic signal
Implementation Method 2
the nonlinear elements are a first Schottky diode and a second Schottky diode
Implementation Method 3
a first transmission line section coupled to deliver the input periodic signal and a bias voltage to the first Schottky diode
Implementation Method 4
a bias voltage is established on the bias capacitor based on the input periodic signal
Data Source
AI summary
Comb generators include a nonlinear transmission line (NLTL) having one or more NLTL sections. Each NLTL section includes one or more nonlinear elements and transmission line portions that provide transmission line dispersion. Typically, the nonlinear elements are Schottky diodes, and a pulse forming bias network is configured to establish Schottky diode bias conditions using a periodic signal that is input to the comb generator. For input periodic signals at frequencies between about 500 MHz and 1 GHz, output signals are produced having substantial power in frequency components at frequencies up to at least about 50 GHz.