Slot-Coupled Antenna Structure With Matching Circuits for Multiband VSWR

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Solution Overview

Problem

Existing antenna structures in communications terminals suffer from poor performance due to a high voltage standing wave ratio, which affects their efficiency and reliability across multiple frequency bands.

Innovation Solution

The antenna structure incorporates a first and second antenna radiator coupled through a slot, with impedance matching circuits to adjust impedance and reduce voltage standing wave ratio, including specific components like inductors and capacitors to match the signal source impedance to 50 ohms, thereby improving radiation performance across frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an antenna is disposed in a communications terminal with metal middle frame or all-metal battery cover to work in multiple frequency bands, then the antenna can operate across broad frequency ranges (1.55-1.62 GHz, 2.4-2.5 GHz, 5.15-5.85 GHz), but the voltage standing wave ratio becomes relatively large resulting in poor antenna performance

Engineering Contradiction:
Improvefrequency band coverageVSAvoidantenna performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by introducing adjustable impedance matching circuits that can dynamically modify electrical parameters (inductance and capacitance values) to optimize the voltage standing wave ratio across different frequency bands. The impedance matching circuit includes variable inductors and capacitors that can be tuned to achieve optimal performance in each frequency band (1.55-1.62 GHz, 2.4-2.5 GHz, 5.15-5.85 GHz), thereby resolving the contradiction between broad frequency coverage and maintained performance reliability.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the antenna structure uses a simple configuration without impedance matching circuits, then the device complexity is reduced, but the voltage standing wave ratio remains high causing poor radiation performance

Engineering Contradiction:
Improveantenna structure simplicityVSAvoidradiation performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces an impedance matching circuit as an intermediary component between the signal source and the antenna radiator. This intermediary circuit includes inductors and capacitors that mediate the impedance transformation, matching the source impedance to the antenna input impedance across multiple frequency bands. The intermediary circuit resolves the contradiction by adding only the necessary components to achieve performance improvement without excessive complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 the voltage standing wave ratio, enhances antenna efficiency, and resolves radiation performance contradictions across different frequency bands, particularly improving performance in the WIFI5G band from 5.15 GHz to 5.85 GHz.

Implementation Method 1

a first antenna radiator (1), a second antenna radiator (2)... The first antenna radiator (1) is coupled to the second antenna radiator (2) through a slot

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

including specific components like inductors and capacitors to match the signal source impedance to 50 ohms

Methodology Applied
Scientific EffectImpedance matching: Capacitance

Implementation Method 3

including specific components like inductors and capacitors to match the signal source impedance to 50 ohms

Methodology Applied
Scientific EffectInductance: Inductor

Implementation Method 4

The first antenna radiator (1) is coupled to the second antenna radiator (2) through a slot, an end of the first antenna radiator (1) away from the slot is grounded, a feed point (11) is disposed on the first antenna radiator (1)

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP3896791B1Antenna structure and communication terminal
Publication Date: 2023.08.23 VIVO MOBILE COMM CO LTD

AI summary

Provided in the present application are an antenna structure and a communication terminal. The antenna structure comprises a first antenna radiator, a second antenna radiator, a first impedance matching circuit, a second impedance matching circuit, and a signal source, wherein the first antenna radiator is coupled to the second antenna radiator by means of a slot; the end of the first antenna radiator away from the slot is grounded, and the first antenna radiator is provided with a feed point, the end of the second antenna radiator away from the slot is grounded, and an absolute value of the difference between the length of the second antenna radiator and the 1/4 wavelength of a third frequency band is less than a first specific value; a first end of the first impedance matching circuit is connected to the feed point, and a second end of the first impedance matching circuit is connected to a first end of the signal source; a first end of the second impedance matching circuit is connected to a third end of the first impedance matching circuit, and a second end of the second impedance matching circuit is grounded; and a second end of the signal source is grounded.