Multi-Band Inverted-F Antenna Layout With Dual-Resonance Coil

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Solution Overview

Problem

Existing planar antennas are limited in handling multiple frequency bands due to their layout characteristics, leading to increased space, material, and production costs, as well as impaired performance due to additional circuitry and components, which absorb radio waves rather than transmitting them efficiently.

Innovation Solution

A planar antenna design featuring a coil as the only discrete electrical component in the grounding leg, acting as both a capacitor for higher frequencies and an inductor for lower frequencies, with planar conductors optimized for specific frequency ranges and connected via vias to minimize component count and maximize air exposure for efficient signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple antennas are included to handle multiple frequency bands, then frequency band coverage is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improvefrequency band coverageVSAvoidnumber of antennas and circuitry
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a single antenna structure that can operate across multiple frequency bands by utilizing a radiation element with multiple resonant frequencies. The antenna is designed to resonate at fundamental and harmonic frequencies, allowing one antenna to perform the function of multiple antennas, thereby reducing device complexity while maintaining broad frequency band coverage.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the electrical parameters of the antenna by introducing a shunt capacitor that can be switched between different states (connected or disconnected). This parameter change allows the antenna to adjust its resonant frequencies and impedance characteristics to match different frequency bands, enabling multi-band operation without requiring multiple separate antennas.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If additional circuitry is added for impedance matching and tuning, then frequency band handling is improved, but production cost and material requirements increase

Engineering Contradiction:
Improvefrequency band handling capabilityVSAvoidproduction cost and material requirements
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The shunt capacitor serves multiple functions simultaneously: it provides impedance matching for different frequency bands, enables resonance tuning, and allows the antenna to switch between fundamental and harmonic frequency operations. This single component performs what would traditionally require multiple separate circuit elements, thereby reducing material requirements and production cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If more components are used to achieve multi-band operation, then frequency range is improved, but performance deteriorates due to increased losses

Engineering Contradiction:
Improvefrequency rangeVSAvoidsignal losses
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts and eliminates unnecessary intermediate components from the antenna system. By using a direct shunt capacitor connection to the ground plane without additional series capacitors or complex matching networks, the design reduces the number of conductive elements that would otherwise introduce resistive losses and degrade signal quality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent optimizes the capacitor's electrical parameters (capacitance value, Q-factor) to minimize energy losses. By selecting a capacitor with appropriate characteristics and positioning it optimally, the design achieves efficient impedance matching with minimal insertion loss, maintaining high performance across multiple frequency bands.

Inventive Principle:
Principle #35Parameter changes

4Area of stationary object

If antenna elements are placed closer together to reduce space, then compactness is improved, but performance deteriorates due to reduced air exposure

Engineering Contradiction:
Improvespace requirementsVSAvoidradio wave absorption
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The patent utilizes the third dimension (vertical spacing) to maintain performance while reducing the planar footprint. By elevating the radiation element above the ground plane at an optimized height, the antenna creates effective radiating area in the vertical dimension, allowing compact planar dimensions without sacrificing the air exposure needed for efficient radio wave transmission.

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

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

The antenna achieves efficient wireless communication on multiple frequency bands with reduced component count, minimizing losses and production costs while maintaining high performance and compact design, suitable for devices requiring broad frequency coverage.

Implementation Method 1

A planar antenna design featuring a coil as the only discrete electrical component in the grounding leg, acting as both a capacitor for higher frequencies and an inductor for lower frequencies

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

A planar antenna design featuring a coil as the only discrete electrical component in the grounding leg, acting as both a capacitor for higher frequencies and an inductor for lower frequencies

Methodology Applied
Scientific EffectInductance: Inductor

Implementation Method 3

a first planar conductor, which is adapted to resonate at frequencies of a first frequency range, as well as a second planar conductor, which is adapted to resonate at frequencies of a second frequency range

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3813190B1Substrate integrated multi band inverted f antenna
Publication Date: 2024.01.03 ASCOM SWEDEN
  • EP3813190B1 patent drawingFigure 1
  • EP3813190B1 patent drawingFigure 2
  • EP3813190B1 patent drawingFigure 3

AI summary

The present disclosure provides an antenna (100) for wireless communication that includes a first planar conductor (110), which is adapted to resonate at frequencies of a first frequency range; and a second planar conductor (120), which is adapted to resonate at frequencies of a second frequency range that spans lower frequencies than the first frequency range. Thus, a compact and efficient antenna layout is provided that enables reception and transmission of radio signals on multiple frequency bands.