Multilayer Antenna Module Stub Layout for Wider Band and Lower Return Loss
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Solution Overview
Problem
Existing antenna modules with stub configurations, as described in Japanese Unexamined Patent Application Publication No. 2002-271131, require further improvements in antenna characteristics such as antenna gain and return loss.
Innovation Solution
The antenna module incorporates a dielectric substrate with a multilayer structure, a ground electrode, a plate-like fed element, and a first stub branching off from the feed line, where the open end of the stub coincides with the fed or unfed element when viewed in plan view, enhancing antenna characteristics by improving symmetry of current distribution and impedance control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a stub is provided in the transmission line to widen the supported band, then the frequency band width is improved, but the antenna gain and return loss characteristics deteriorate
Solution Approach 1:
The patent applies local quality by positioning the stub's open end at a specific location that coincides with the fed element when viewed in plan view. This localized positioning optimizes the electromagnetic field distribution at the critical interaction region between the stub and fed element, thereby improving antenna gain and return loss while maintaining the band-widening function of the stub.
Solution Approach 2:
The patent utilizes the vertical dimension (layer structure) to resolve the contradiction. By disposing the stub between the fed element and ground electrode in a different layer, and positioning its open end to coincide with the fed element in plan view, the invention creates a three-dimensional configuration that optimizes both band width and antenna characteristics simultaneously.
2Reliability
If the stub open end coincides with the fed element in plan view, then antenna gain is improved, but the structural complexity increases
Solution Approach 1:
The stub structure serves multiple functions: it widens the frequency band by providing reactive impedance compensation, improves antenna gain through optimized current distribution when its open end coincides with the fed element, and maintains compact integration within the multilayer substrate. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The patent merges the stub structure with the existing transmission line and positioning it to coincide with the fed element, combining multiple functions (impedance matching, band widening, and gain enhancement) into a single integrated structure rather than using separate components.
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 results in improved antenna gain and wider frequency band width, with enhanced symmetry of current distribution in the ground electrode, leading to better radiation direction and reduced return loss.
Implementation Method 1
a first stub branching off from the first feed line at a first branch point of the first feed line. The first stub has a first open end. The first stub is disposed between the fed element and the ground electrode. When the dielectric substrate is viewed in plan view, the first open end coincides with the fed element.
Data Source
AI summary
An antenna module includes a dielectric substrate having a multilayer structure, a ground electrode disposed in the dielectric substrate, a plate-like fed element facing the ground electrode and disposed at a layer different from a layer including the ground electrode, a feed line for transferring a radio-frequency signal to a feed point of the fed element, and a stub. The stub branches off from the feed line at a branch point of the feed line and has an open end. The stub is disposed between the fed element and the ground electrode. When the dielectric substrate is viewed in plan view, the open end coincides with the fed element.