Chip Antenna Bandwidth Enhancement via Coupling Plate
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Solution Overview
Problem
Existing antenna devices face limitations in bandwidth enhancement due to the distance between radiating and parasitic conductor elements, and suffer from matching losses when connected to feed lines, especially in millimeter wave applications, where the small size makes power feeding difficult and increases manufacturing costs due to the need for low dielectric loss materials.
Innovation Solution
The antenna device incorporates a laminated chip antenna with a radiating conductor element, a parasitic conductor element, and a coupling adjusting conductor plate on a mother substrate, where the coupling adjusting conductor plate adjusts the electromagnetic coupling between the radiating and parasitic elements, and omits a ground conductor plate to enhance matching with the feed line, using a land grid array for connection and a low dielectric loss tangent material like LTCC for the laminated body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ground conductor plate is provided in the chip antenna, then the antenna structure is complete and stable, but matching losses occur when connected to the feed line
Solution Approach 1:
The ground conductor plate is extracted (removed) from the chip antenna structure. The patent describes that the chip antenna includes a radiating conductor element and a parasitic conductor element, but deliberately omits the ground conductor plate that would normally be present in conventional microstrip antennas. This extraction eliminates the source of matching losses while maintaining structural stability through the laminated substrate and feed line design.
2Adaptability or versatility
If the distance between radiating and parasitic conductor elements is increased, then bandwidth enhancement is achieved, but the antenna size increases
Solution Approach 1:
The patent utilizes the thickness direction (z-axis) of the laminated substrate as an additional dimension to achieve bandwidth enhancement. By positioning the radiating conductor element and parasitic conductor element at different heights within the laminated structure, the design achieves magnetic coupling and bandwidth enhancement without increasing the planar footprint. The coupling adjusting conductor plate further optimizes this three-dimensional coupling arrangement.
Solution Approach 2:
The patent changes the physical parameters of the antenna structure by introducing a coupling adjusting conductor plate with specific dimensions and positioning. The plate's size, shape, and location are optimized to control the coupling strength between radiating and parasitic elements, thereby adjusting the resonant frequencies and bandwidth without requiring larger physical dimensions.
3Manufacturing precision
If low dielectric loss tangent materials are used, then manufacturing precision and signal quality improve, but manufacturing costs increase
Solution Approach 1:
The patent employs conventional, cost-effective laminated substrate materials with moderate dielectric properties rather than expensive low-loss materials. The design compensates for any signal quality limitations through optimized geometric parameters, coupling structures, and the groundless configuration that reduces unwanted capacitances. This approach achieves acceptable signal quality at lower manufacturing costs.
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 increases the frequency range and bandwidth of reflectivity and antenna gain while reducing manufacturing costs and stray capacitance, facilitating application in miniature devices without the need for expensive low dielectric loss materials.
Implementation Method 1
The antenna device according to Japanese Unexamined Patent Application Publication No. 55-93305 achieves bandwidth enhancement by exploiting magnetic coupling between the radiating conductor element and the parasitic conductor element.
Implementation Method 2
a radiating conductor element located inside the laminated body, sandwiched between two of the insulating layers, and connected to the feed line of the mother substrate
Data Source
AI summary
A chip antenna is mounted on a mother substrate including a feed line. In a representative embodiment, the chip antenna includes a laminated body including plural insulating layers, a radiating conductor element, a parasitic conductor element, a coupling adjusting conductor plate, and a LGA. The radiating conductor element is connected to the feed line via a first flat electrode pad of the LGA. On the other hand, the coupling adjusting conductor plate is provided between the radiating conductor element and the parasitic conductor element, and both end sides of the coupling adjusting conductor plate are connected to second and third flat electrode pads of the LGA. Another representative embodiment does not include a coupling adjusting conductor plate in the laminated body and includes an LGA that may or may not include second and third flat electrode pads.