Millimeter-Wave Transmission-Line Conversion Structure
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Solution Overview
Problem
Existing transmission-line conversion structures for millimeter-wave bands face challenges in impedance matching between microstrip lines and waveguides, leading to manufacturing difficulties and non-uniformity in characteristics, especially when dealing with multiple signal terminals and bends.
Innovation Solution
A transmission-line conversion structure that uses a waveguide with a transmission line filled with dielectric material having a relative permittivity greater than 1, where the transmission line is surrounded by metal walls and bonded to both the microstrip line and waveguide, with specific impedance and length settings to achieve impedance matching and efficient wave propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ridge portion of a ridge waveguide is brought into contact with a microstrip line, then impedance matching between microstrip line and waveguide is achieved, but manufacturing difficulty increases and assembling accuracy requirements become extremely high
Solution Approach 1:
A transmission line with dielectric material filling is introduced as an intermediary component between the microstrip line and the waveguide. This intermediate transmission line provides a gradual impedance transition, mediating the connection between the two different transmission line types and achieving impedance matching without requiring direct contact between the ridge portion and microstrip line.
Solution Approach 2:
The impedance transformation is achieved by changing the dielectric constant parameter of the filling material in the intermediate transmission line. By selecting appropriate dielectric materials with specific permittivity values, the impedance of the intermediate line is optimized to provide smooth transition between the microstrip line (50-100Ω) and the waveguide (several hundreds of Ω).
2Adaptability or versatility
If many waveguides are arranged perpendicular to the rear ends of strip lines to connect multiple signal terminals, then all terminals can be connected, but the conversion structure becomes extremely difficult to manufacture
Solution Approach 1:
The connection structure is segmented into modular units, each consisting of a microstrip line connected to a waveguide through the intermediate transmission line. This segmentation allows each connection point to be independently manufactured and assembled, significantly reducing the overall manufacturing difficulty compared to creating a monolithic structure with multiple perpendicular waveguides.
Solution Approach 2:
Instead of arranging multiple waveguides in a perpendicular fashion (adding complexity in three dimensions), the invention transitions to a planar configuration where all connections are made in a two-dimensional plane. The intermediate transmission lines are arranged side-by-side, eliminating the need for vertical stacking and complex spatial arrangements.
3Ease of manufacture
If bends are provided in the middle portions of waveguides to avoid perpendicular arrangement, then manufacturing becomes easier, but the entire system becomes large
Solution Approach 1:
The bending sections are extracted and eliminated from the design. By using the planar intermediate transmission line configuration, the need for bends in the waveguide middle portions is removed entirely. The straight-line connection achieved through the intermediate transmission line minimizes the overall system footprint while maintaining manufacturing ease.
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 allows for easy manufacturing of a compact transmission-line conversion structure with minimal non-uniformity, enabling efficient propagation of millimeter-wave signals across a wide band by matching the impedance of microstrip lines and waveguides, thus ensuring high versatility and performance.
Implementation Method 1
the transmission line is filled with a dielectric material having relative permittivity of greater than 1
Data Source
AI summary
To provide a transmission-line conversion structure for a millimeter-wave band capable of being easily manufactured with a small size without easily causing non-uniformity in characteristics in a wide band. A transmission-line conversion structure for a millimeter-wave band that connects a microstrip line (10), which includes a main conductor (12) formed on one surface of a dielectric substrate (11) and a ground conductor (13) formed on the other surface thereof, with a waveguide (20) has a waveguide structure in which a transmission line (31) having a predetermined length is formed so as to be surrounded by metal walls (32). The transmission line is filled with a dielectric material having a relative permittivity of greater than 1. The transmission-line conversion structure allows electronic waves of a millimeter-wave band in a longitudinal direction of the main conductor.