Antenna Systems with Low Passive Intermodulation
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Solution Overview
Problem
Conventional antenna systems face challenges in achieving low passive intermodulation (PIM), good bandwidth, and compact design for multi-antenna applications, particularly in infrastructure systems like customer premises equipment and in-building systems, where multiple antennas need to be integrated in a small space while maintaining omnidirectional radiation patterns and low profile.
Innovation Solution
The design incorporates an upper radiating patch element, a ground plane, and feeding elements with proximity or direct galvanic coupling, along with a shorting element, to minimize metal-to-metal contact and reduce PIM, while using non-ferromagnetic materials and dielectric insulation to enhance bandwidth and isolation, allowing for multiple antennas in a smaller footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple antennas are placed in close proximity within a low profile radome to achieve compact design and omnidirectional radiation patterns, then device compactness and radiation performance are improved, but passive intermodulation (PIM) increases due to increased metal-to-metal contact
Solution Approach 1:
The patent introduces dielectric members as intermediary elements between metal components (radiating elements, ground plane, shorting elements, feeding elements). These dielectric intermediaries eliminate direct metal-to-metal contact while maintaining the structural integrity and electrical coupling necessary for antenna operation, thereby reducing PIM generation in compact multi-antenna configurations
Solution Approach 2:
The patent employs composite construction by combining dielectric materials with metal components. The dielectric members are integrated with metal radiating elements, ground planes, and shorting elements to create a hybrid structure that maintains the benefits of metal (conductivity, mechanical strength) while eliminating harmful metal-to-metal contacts through dielectric separation
2Volume of moving object
If conventional planar inverted-F antennas are used to achieve low profile and compact design, then device compactness is improved, but bandwidth is limited
Solution Approach 1:
The patent segments the antenna structure into distinct functional components: radiating elements, ground plane, shorting elements, and feeding elements. This segmentation allows each component to be optimized independently for both compactness and bandwidth performance, with the overall structure achieving enhanced bandwidth through the coordinated interaction of segmented parts
Solution Approach 2:
The patent extends the conventional planar inverted-F antenna structure into the vertical dimension by incorporating elevated radiating elements positioned above the ground plane. This dimensional transition from purely planar to three-dimensional configuration enables increased bandwidth while maintaining low profile through optimized vertical spacing and grounding
3Productivity
If multiple antennas are integrated in a small space for multi-antenna applications, then capacity and coverage are improved, but isolation between antennas deteriorates
Solution Approach 1:
Dielectric members are positioned between adjacent antennas to act as isolating intermediaries. These dielectric barriers reduce electromagnetic coupling and interference between closely spaced antennas, improving isolation while allowing the antennas to maintain close proximity for compact system integration and high capacity
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 achieves low PIM, improved bandwidth, and isolation, enabling compact, omnidirectional antenna systems that meet LTE/4G frequency bands and provide design flexibility for modular concepts, accommodating both pigtail and fixed connectors with consistent performance.
Implementation Method 1
a first feeding element electrically coupling (e.g., via capacitive coupling or direct galvanic coupling) the upper radiating patch element to a feed point
Implementation Method 2
a first feeding element electrically coupling (e.g., via capacitive coupling or direct galvanic coupling) the upper radiating patch element to a feed point
Implementation Method 3
a shorting element electrically coupling (e.g., via proximity coupling or direct galvanic coupling) the upper radiating patch element to the ground plane
Implementation Method 4
a shorting element electrically coupling (e.g., via proximity coupling or direct galvanic coupling) the upper radiating patch element to the ground plane
Data Source
AI summary
Exemplary embodiments are provided of antennas and antenna systems including the same. In an exemplary embodiment, an antenna generally includes an upper radiating patch element, a ground plane spaced apart from the upper radiating patch element, and a feed point positioned adjacent the ground plane. A first feeding element electrically couples (e.g., via proximity coupling or direct galvanic coupling) the upper radiating patch element to the feed point. A second feeding element electrically couples (e.g., via proximity coupling or direct galvanic coupling) the upper radiating patch element to the feed point. A shorting element electrically couples (e.g., via proximity coupling or direct galvanic coupling) the upper radiating patch element to the ground plane. In other exemplary embodiments, the antenna systems include one or more ground planes and one or more antennas.