Patch Antenna Feed Using Capacitive Coupling

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Solution Overview

Problem

Existing patch antennas require significant substrate area and cause intrusions in the ground plane due to feed configurations, especially when multiple feeds are needed for circular polarization, and existing solutions are costly and inefficient in terms of substrate usage.

Innovation Solution

A patch antenna arrangement using a sandwich configuration with two microwave substrates and capacitive feeds, where the second substrate can be a non-microwave substrate like a low-cost PCB, reducing the need for expensive high-Q substrates and minimizing intrusions in the ground plane by using capacitive coupling with overlapping areas between the feed and patch antenna.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If aperture coupled feed is used to avoid conductor traversal, then ease of manufacture is improved, but substrate area is increased due to slot type apertures

Engineering Contradiction:
Improveease of manufactureVSAvoidsubstrate area
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The harmful slot type apertures are extracted and removed from the ground plane. Instead of using aperture coupling that requires large slots, the invention uses probe feeds that traverse through the substrate thickness, eliminating the need for large aperture areas while maintaining ease of manufacture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The solution moves from a 2D aperture coupling approach to a 3D probe feed approach. The feed structure extends through the substrate thickness dimension, allowing electrical connection without requiring large lateral aperture areas in the ground plane, thus reducing substrate area usage.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple feeds are used for circular polarization, then adaptability is improved, but substrate area is increased and ground plane intrusions are aggravated

Engineering Contradiction:
ImproveadaptabilityVSAvoidsubstrate area
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Multiple feed structures are merged and closely spaced on the substrate. The probe feeds are positioned adjacent to each other with minimal separation, allowing dual-orthogonal feeds for circular polarization to be implemented without requiring large substrate area, as the feeds share the same substrate real estate rather than requiring separate aperture regions.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If substrate with well-defined electrical properties is used, then reliability is improved, but cost is increased

Engineering Contradiction:
ImprovereliabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention uses standard, inexpensive substrate materials with adequate electrical properties rather than expensive high-Q microwave substrates. While the substrates are not premium quality, they provide sufficient performance for the application, reducing cost while maintaining acceptable reliability through the optimized feed结构设计.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Ease of manufacture

If probe or coaxial type feed is used, then ease of manufacture is improved, but device complexity is increased due to conductor traversal requirements

Engineering Contradiction:
Improveease of manufactureVSAvoiddevice complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The substrate itself provides the conductor traversal path through its thickness. The substrate structure is utilized to accommodate the feed conductors, with the substrate acting as its own mounting and support structure, eliminating the need for separate complex feed mounting mechanisms or additional structural components.

Inventive Principle:
Principle #25Self-service

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 reduces substrate area usage, minimizes intrusions in the ground plane, and maintains well-defined electrical properties while allowing for efficient capacitive coupling, thereby enhancing the design's efficiency and cost-effectiveness.

Implementation Method 1

Each of said at least two pads, each relating to a feed, has an individual corresponding opening in the ground plane for capacitively coupling each of said at least two feeds to the patch antenna

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3596778B1Patch antenna feed
Publication Date: 2023.06.07 NORBIT ITS
  • EP3596778B1 patent drawingFigure 1A
  • EP3596778B1 patent drawingFigure 1B
  • EP3596778B1 patent drawingFigure 2

AI summary

Present teachings relate to an antenna arrangement comprising, a first substrate comprising a first surface and a second surface, the first surface and the second surface being opposite sides of the first substrate, a second substrate comprising a third surface and a fourth surface, the third surface and the fourth surface being opposite sides of the second substrate, a patch antenna being realized in a first electrically conductive material attached to the first surface, a ground plane being realized in a second electrically conductive material attached to the second surface, and at least two feeds realized in a third electrically conductive material attached at least partially to the fourth surface. The patch antenna is arranged with respect to the ground plane so as to form a resonant antenna. The first substrate and the second substrate are adapted to be held in close proximity or in contact such that the third surface is facing the second surface, and each of said at least two feeds are having an individual corresponding opening in the ground plane for capacitively coupling each of said at least two feeds to the patch antenna, wherein footprint of each of said at least two feeds is smaller than footprint of its corresponding opening in the ground plane. Present teachings also relate to an antenna arrangement where the second substrate is replaced by a dielectric layer, and to a wireless device comprising the antenna arrangement.