Planar Antenna Impedance Matching for Wireless Test Stability
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Solution Overview
Problem
Traditional test devices for wireless electronic devices experience unstable measurement results due to variations in the size and position of the device under test, caused by irregular electromagnetic field distributions from cone-shaped measurement antennas.
Innovation Solution
A test device with a metal casing, RF-absorbing material, and an impedance adjustment module, featuring a sheet-like measurement antenna and dielectric components to ensure even electromagnetic field distribution and impedance matching, thereby stabilizing signal measurements regardless of device size or position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cone-shaped measurement antenna is used to produce electromagnetic field in the shielding box, then the wireless electronic device can be tested, but the electromagnetic field has irregular magnitude causing unstable measurement results when device position or size changes
Solution Approach 1:
The patent changes the geometric parameters of the measurement antenna from a conventional cone shape to a specifically designed planar structure with controlled dimensions. The antenna includes a feed-in portion and a measurement portion with specific length and width parameters that can be adjusted to control the electromagnetic field distribution, transforming the irregular field into a more uniform pattern for stable measurements regardless of device position or size variations
Solution Approach 2:
The patent employs an asymmetric planar antenna structure rather than a symmetric cone shape. The measurement antenna has a specific geometric configuration with the measurement portion extending in particular directions, creating an asymmetric electromagnetic field distribution that provides more uniform coverage and stable measurement results across different device positions within the shielding box
2Object-affected harmful factors
If wave-absorbing material is disposed on the inner surface of the metal casing to absorb wireless signals, then signal reflections are reduced, but the electromagnetic field distribution becomes irregular affecting measurement accuracy
Solution Approach 1:
The patent applies wave-absorbing material selectively at specific locations within the shielding box rather than uniformly covering all inner surfaces. The material is positioned strategically to absorb reflections from critical areas while preserving the electromagnetic field distribution in the measurement region, thus reducing harmful reflections without compromising field uniformity
Solution Approach 2:
The patent introduces wave-absorbing material as an intermediary element between the metal casing and the measurement region. This material acts as a mediator that absorbs unwanted reflected signals while allowing the desired electromagnetic field to pass through, improving signal quality without disrupting the overall field distribution pattern
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 and consistent wireless signal measurements by ensuring an evenly distributed electromagnetic field and minimizing signal loss, resulting in reliable performance evaluation of wireless electronic devices.
Implementation Method 1
the wave-absorbing material 20 is disposed on an inner surface of the metal casing 11 for absorbing the wireless signal transmitted from a wireless electronic device under test 50 to the metal casing 11
Implementation Method 2
The impedance adjustment module includes a dielectric layer, a microstrip line, and a slot line. The microstrip line and the slot line are disposed at opposite sides of the dielectric layer
Data Source
AI summary
A test device for wireless electronic devices includes a metal casing, a RF-absorbing material, a measurement antenna, and an impedance adjustment module. The impedance adjustment module includes a dielectric layer, a microstrip line, and a slot line, wherein the slot line is electrically connected to the measurement antenna. The microstrip line and the slot line are disposed on two opposite sides of the dielectric layer and respectively include a first body and a second body, which are parallel to each other.