Wire Loop Signal Coupler With Conical Opening for High Directivity
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Solution Overview
Problem
Existing bi-directional signal couplers in microwave testing face challenges in maintaining high directivity when operating under non-50Ω impedance conditions, leading to reduced signal detection and isolation efficiency, particularly in load pull measurements.
Innovation Solution
A high directivity bi-directional signal coupler design featuring an electro-magnetic wire loop protruding through a conical or recessed opening in the transmission line, optimizing electric and magnetic field concentration to enhance capacitive and magnetic current induction, thereby increasing directivity and coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional bi-directional signal couplers are used in non-50Ω test environments, then the coupler can operate under various impedance conditions, but the directivity deteriorates leading to reduced signal detection and isolation efficiency
Solution Approach 1:
The patent applies local quality by creating asymmetric field distribution within the coupler structure. The wire loop is positioned and dimensioned to create different coupling strengths for forward and reverse waves, with the loop size and position optimized to maximize directivity under non-50Ω conditions while maintaining adaptability across impedance ranges
Solution Approach 2:
The patent implements asymmetry through the wire loop configuration where the loop is intentionally designed with unequal coupling to forward and reverse traveling waves. This asymmetric coupling mechanism, controlled by loop dimensions and position, enables the coupler to achieve high directivity in non-50Ω environments by creating unequal signal paths for different wave directions
2Measurement precision
If the coupler is designed for high directivity in non-50Ω environments, then signal isolation improves, but the coupling efficiency may be compromised
Solution Approach 1:
The patent applies dynamics by making the coupling characteristics tunable through the wire loop configuration. The loop can be adjusted in position and orientation to dynamically optimize the balance between directivity and coupling efficiency for different test conditions, allowing the coupler to adapt its coupling strength while maintaining isolation performance
Solution Approach 2:
The patent implements parameter changes by varying the wire loop dimensions, position, and orientation to optimize both directivity and coupling efficiency. The loop area, distance from the transmission line, and angular orientation are tuned as parameters to achieve the desired balance between signal isolation and coupling strength for non-50Ω environments
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 coupler achieves superior coupling-to-directivity ratios and allows for tuning to achieve extremely high directivity without compromising forward coupling, outperforming conventional designs in non-50Ω test environments.
Implementation Method 1
The coupler is made by immerging to a certain degree the 'U'-shaped electro-magnetic loop sensor through the opening in the metallic mantle into the electromagnetic field TEM field in the waveguide cavity or surrounding the signal conductor and sampling a small part (ca. 0.1%) of the transported energy
Implementation Method 2
optimizing electric and magnetic field concentration to enhance capacitive and magnetic current induction
Data Source
AI summary
Low loss high directivity wire couplers use a transmission airline structure and a low diameter coaxial cable ending in a wire loop sensor, which is inserted into an elliptically formed conical opening of the ground wall of the transmission line and protrudes into its cavity leading into a coupled and an isolated port. Lower, capacitively induced, electrical currents, because of the protruding ground edges of the conical or recessed openings, compared with the unperturbed antiphase magnetically induced currents, lead to controlled higher directivity in a frequency range up to at least 170 GHz.