All-Pass Phase-Shift Network With High-Pass Sections for Wide Bandwidth
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Solution Overview
Problem
Simple lattice networks used in phase-shift networks are limited by parasitic reactances at high frequencies, restricting their bandwidth and making them unsuitable for high-frequency applications.
Innovation Solution
A phase-shift network design incorporating capacitors and filter sections with inductors and high-pass networks, allowing for balanced signal propagation and phase shifting without frequency limitations, realized in a compact configuration using printed circuit board metallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a simple lattice network with series inductors and cross connected capacitors is used, then the network provides low loss and economical construction, but parasitic reactances become significant at high frequencies limiting the bandwidth
Solution Approach 1:
The patent transforms the simple lattice network into a composite structure by introducing high-pass filter sections with specific inductance and capacitance values. This parameter modification allows the network to maintain low loss characteristics while extending operational bandwidth from limited high-frequency performance to 20 MHz - 1 GHz range by carefully selecting L and C values that compensate for parasitic effects.
Solution Approach 2:
The invention creates a composite phase-shift network by combining the traditional lattice structure with high-pass filter sections. This composite approach integrates multiple functional elements (series inductors, shunt capacitors, and high-pass networks) to achieve both low loss and extended bandwidth that neither simple lattice nor basic high-pass filters could provide alone.
2Device complexity
If a simple lattice network is used, then the construction is compact and economical, but the network is not sufficient in terms of bandwidth for high-frequency applications
Solution Approach 1:
The patent divides the phase-shift network into distinct functional segments: the original lattice structure and additional high-pass filter sections. Each segment performs a specific function - the lattice provides basic phase shifting with low loss, while the high-pass sections extend bandwidth. This segmentation allows modular design and maintenance of compact construction while achieving extended frequency coverage.
3Reliability
If phase-shift networks with frequency cutoffs outside the bandwidth of interest are used, then they are useful in high-frequency coupling circuits, but they may introduce frequency limitations for the overall circuit
Solution Approach 1:
The patent designs the phase-shift network to perform multiple functions simultaneously: it provides phase shifting, maintains low loss, extends bandwidth to 20 MHz - 1 GHz, and ensures frequency cutoffs remain outside the operational bandwidth. The high-pass filter sections with strategically placed inductors and capacitors create frequency response characteristics that satisfy multiple circuit requirements without introducing limiting cutoffs within the desired frequency range.
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 solution provides a phase-shift network with extended bandwidth and low loss, capable of maintaining consistent phase difference across a wide frequency range, from 20 MHz to 1 GHz, with phase shifts approaching 180 degrees at higher frequencies.
Implementation Method 1
A phase-shift network may include a first capacitor connected between a first input node and a first output node, and a second capacitor connected between a second input node and a second output node
Implementation Method 2
a first filter section may be connected between the first input node and the second output node, and a second filter section may be connected between the second input node and the first output node. One or both of the first and second filter sections may include an inductance
Implementation Method 3
One or both of the first and second filter sections may include an inductance and a high-pass network. The high-pass network may include third and fourth capacitors and a first inductor
Data Source
AI summary
A phase-shift network may include a first capacitor connected between a first input node and a first output node, and a second capacitor connected between a second input node and a second output node. Further, a 5 first filter section may be connected between the first input node and the second output node, and a second filter section may be connected between the second input node and the first output node. One or both of the first and second filter sections may include an inductance and a high-pass network. The high-pass network may include third and fourth capacitors and a first inductor. The inductance and third and fourth capacitors may be connected in series between the respective input and output nodes. The first inductor may have a first end connected to an intermediate node between the third and fourth capacitors and a second end connected to a circuit ground.