Patch Antenna Feed Circuit for Stable Millimeter-Wave Output
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Solution Overview
Problem
Existing antenna modules experience unstable output characteristics due to fluctuations in load impedance, particularly in millimeter wave and sub-terahertz bands, where the output power of amplifiers fluctuates significantly without filters between the amplifiers and the load.
Innovation Solution
The antenna module incorporates a transformer and a ¼ wavelength transmission line to stabilize output characteristics by averaging the impedance fluctuations, using a differential amplifying-type configuration with opposing phases of signals from power amplifiers and a patch antenna with dual feed points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If filters are not used between amplifiers and load, then device complexity is reduced, but output characteristics become unstable due to impedance fluctuations
Solution Approach 1:
The patent introduces a transformer as an intermediary component between the power amplifiers and the antenna load. The transformer couples the amplifiers to the load through magnetic coupling, which isolates the amplifiers from direct impedance variations of the antenna. This intermediary structure allows the system to maintain stable output characteristics without requiring complex filter circuits, thus resolving the contradiction between device complexity and output stability.
2Adaptability or versatility
If output impedance fluctuates with load impedance, then adaptability to different loads is improved, but output power stability deteriorates
Solution Approach 1:
The patent segments the impedance matching function into two parts: the transformer handles the primary impedance transformation and isolation, while the ¼ wavelength transmission line provides additional impedance transformation. This segmentation allows the system to adapt to different load impedances through the combined action of these two components while maintaining stable output power, as each component contributes to impedance management without directly coupling load variations to the amplifiers.
Solution Approach 2:
The patent utilizes the electrical length parameter of the ¼ wavelength transmission line to achieve impedance transformation. By setting the transmission line length to ¼ wavelength, the system transforms the load impedance in a controlled manner. This parameter-based approach allows the system to adapt to different loads while maintaining output power stability, as the transmission line's impedance transformation property compensates for load variations without requiring active control or complex circuitry.
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 stable output characteristics by suppressing impedance fluctuations, maintaining consistent performance even without filters, and ensuring stable output power across varying load impedances.
Implementation Method 1
a first transformer having a first input-side coil and a first output-side coil... An output end of the first power amplifier is connected to one end of the first input-side coil... one end of the first output-side coil is connected to the first feed point
Implementation Method 2
another end of the first output-side coil is connected to one end of the first impedance conversion circuit... another end of the first impedance conversion circuit is connected to the second feed point
Data Source
AI summary
An antenna module includes a patch antenna having feed points, power amplifiers, a transformer having an input-side coil and an output-side coil, and a ¼ wavelength transmission line. An output end of the power amplifier is connected to one end of the input-side coil, an output end of the power amplifier is connected to another end of the input-side coil, one end of the output-side coil is connected to the feed point, another end of the output-side coil is connected to one end of the ¼ wavelength transmission line, and another end of the ¼ wavelength transmission line is connected to the feed point.