Bipolar Pulse Generator With Stepped Transmission-Line Multiplication
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Solution Overview
Problem
Bipolar pulse generators face challenges in achieving high impedance transformation ratios efficiently and compactly, particularly when dealing with low characteristic impedances, which limits their radiation efficiency and size, and they lack simple structures for current multiplication.
Innovation Solution
A bipolar pulse generator design that uses two coupled two-conductor transmission lines with a load between them, where each conductor segment is switchably connected to produce a bipolar pulse, incorporating a stepped transmission line for impedance transformation, allowing for high efficiency and compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional impedance transformers are used to achieve high impedance transformation ratios (≥100), then the radiation efficiency is improved, but the total size becomes large and the design becomes complicated
Solution Approach 1:
The invention divides the impedance transformation function into multiple discrete stages using stepped transmission lines with different characteristic impedances. Each stage provides a specific transformation ratio, and the combination of stages achieves the total required transformation (≥100:1) while maintaining a manageable and systematic design structure.
Solution Approach 2:
The invention changes the characteristic impedance parameter across different transmission line segments to achieve impedance transformation. By carefully selecting the impedance values of each segment (e.g., 50Ω, 75Ω, 100Ω, etc.), the system achieves high transformation ratios without requiring large or complex transformer structures.
2Reliability
If conventional impedance transformers are used to achieve high impedance transformation ratios, then the radiation efficiency is improved, but the total size becomes large
Solution Approach 1:
The impedance transformation is segmented into multiple compact stages using stepped transmission lines. Each segment contributes to the overall transformation ratio, allowing the system to achieve high transformation (≥100:1) in a distributed, space-efficient manner rather than requiring a single large transformer.
Solution Approach 2:
By changing the characteristic impedance parameter across different transmission line segments, the invention achieves compact impedance transformation. The stepped structure allows each segment to be physically small while collectively providing the required transformation ratio, thus reducing the total volume.
3Use of energy by moving object
If low characteristic impedance transmission lines are used to achieve high power and high energy density, then the energy density is improved, but the coupling with radiating impedances becomes problematic
Solution Approach 1:
The coupling between low impedance transmission lines and high impedance radiating elements is achieved through segmented stepped transmission lines. Each segment provides an intermediate impedance level, creating a gradual transition that maintains energy density while enabling effective impedance matching and power transfer.
Solution Approach 2:
The invention uses parameter changes in characteristic impedance across the transmission line segments to bridge the gap between low impedance (mΩ range) transmission lines and high impedance radiating elements. This gradual parameter transition enables effective coupling while preserving the high energy density benefits of low impedance lines.
4Strength
If additional high ratio step-up impedance transformers are used to increase load impedance, then the load voltage is improved, but the efficiency and size of the transformers themselves become problematic
Solution Approach 1:
The voltage transformation is segmented into multiple smaller steps using stepped transmission lines rather than a single large transformer. This segmentation reduces energy losses in each individual transformation stage and improves overall system efficiency while achieving the required load voltage.
Solution Approach 2:
The invention uses gradual parameter changes in characteristic impedance across multiple segments to achieve voltage transformation. This approach minimizes reflective losses and improves efficiency compared to abrupt single-stage transformation, while delivering the required high load voltage.
Data Source
AI summary
A bipolar pulse generator includes two, two-conductor transmission lines coupled together with a load positioned between the two transmission lines. Each conductor of a transmission line we define as a segment. Two segments of one transmission line are charged and switchably coupled to two segments of the other transmission line to produce a bipolar pulse on the matched load. This bipolar pulse generator may be implemented in a flat or a folded design. The generator may include two transmission line structures coupled together with a load positioned between each transmission line structures. The first transmission line structure may include a stepped transmission line and an embedded transmission line segment. A switch may be coupled between the embedded transmission line segment and another segment of the transmission line structure. During operation, the first transmission line structure may be charged to a potential with the switch in the open position and, when the switch is closed, the charge on the first transmission line structure together with the second transmission line structure generates a bipolar pulse on the matched load.