Transformer-Coupled Band-Pass Filter for VCO Phase Noise Suppression
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Solution Overview
Problem
Voltage controlled oscillators (VCOs) face challenges in millimeter wave applications due to phase noise, which introduces second and third-order harmonic spectral components, compromising output quality and requiring effective noise suppression.
Innovation Solution
The implementation of a transformer-coupled bandpass filter (BPF) with coupled capacitors and transformers, which reduces phase noise by filtering out higher harmonics and providing a transmission zero at twice the lower cutoff frequency, thereby enhancing the frequency response and reducing noise by 14 dB or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a VCO operates in millimeter wave applications, then the output frequency is high, but phase noise increases and harmonic spectral components are introduced
Solution Approach 1:
The patent extracts and removes the harmful harmonic spectral components generated by the VCO through a bandpass filter. The filter is designed to pass only the fundamental frequency while blocking the second and third order harmonics, thereby extracting the useful signal and removing the harmful noise components that degrade phase noise performance.
Solution Approach 2:
The patent introduces a bandpass filter as an intermediary component between the VCO and the output. This mediator selectively transmits the desired frequency range while attenuating unwanted harmonics, thus improving phase noise performance without directly modifying the VCO itself.
2Object-generated harmful factors
If a bandpass filter is added to suppress harmonics, then phase noise performance improves, but device complexity increases
Solution Approach 1:
The patent merges the bandpass filter functionality with the existing VCO output stage by integrating the filter elements directly into the oscillator circuit. This combination approach allows harmonic suppression to be achieved without adding a separate, standalone filter module, thereby reducing overall device complexity while maintaining phase noise performance.
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 effectively suppresses phase noise, improving the phase noise performance of VCOs by filtering out higher harmonics and enhancing the signal-to-noise ratio, particularly in high-frequency applications.
Implementation Method 1
The implementation of a transformer-coupled bandpass filter (BPF) with coupled capacitors and transformers
Implementation Method 2
providing a transmission zero at twice the lower cutoff frequency, thereby enhancing the frequency response
Data Source
AI summary
A band-pass filter (BPF) includes first and second windings. The first winding includes first and second terminals, a first outer extending portion extending from the first terminal, a second outer extending portion extending from the second terminal, and a first conductive structure configured to electrically connect the first and second outer extending portions to each other at a location opposite the first and second terminals. The second winding includes third and fourth terminals positioned between the first and second terminals, and a second conductive structure electrically connected to the third and fourth terminals and extending between the first conductive structure and each of the first and second outer extending portions.