Microwave Antenna EBG Structure Surface Wave Suppression

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Solution Overview

Problem

Existing microwave antenna apparatuses using fan-out wafer level packaging technology face challenges with narrow bandwidth, distorted radiation patterns, and high parasitic radiation due to the integration of antenna elements on redistribution layers, which also struggle to efficiently couple RF signals and reduce ripples caused by epoxy and reflectors in PCB layers.

Innovation Solution

Incorporating an electromagnetic band gap (EBG) structure on the PCB layer, coupled to the redistribution layer via solder balls, to suppress unwanted ripples and surface waves, allowing for improved signal coupling and radiation patterns by using EBG modules that mimic an ideal EBG structure on an infinite plane, and integrating various antenna types through package-on-package (PoP) concepts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If antenna elements are printed on redistribution layers (RDLs) in fan-out wafer level packaging, then integration and interconnection between chip and antenna is achieved, but bandwidth becomes narrow (1-5%) and radiation patterns become distorted

Engineering Contradiction:

Improveintegration and interconnectionVSAvoidbandwidth and radiation pattern quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

An electromagnetic band gap (EBG) structure is introduced as an intermediary component between the antenna element and the PCB ground plane. This EBG structure acts as a mediator that suppresses surface waves and parasitic radiation, thereby improving radiation pattern quality and bandwidth without compromising the integrated manufacturing approach

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite structure combining the RDL layer, antenna element, EBG structure with periodic patterns, and PCB substrate. This composite arrangement creates beneficial electromagnetic properties that suppress unwanted surface waves while maintaining the integrated packaging advantages

Inventive Principle:

Principle #40Composite materials

2Reliability

If electromagnetic band gap structures are placed on complete surface under package, then surface waves are suppressed, but coupling elements like solder balls or pins cannot be placed with current manufacturing technology

Engineering Contradiction:

Improvesurface wave suppressionVSAvoidcoupling element placement

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The EBG structure is segmented into specific regions rather than covering the complete surface. By dividing the EBG implementation into functional zones, the patent maintains surface wave suppression capabilities while creating open areas that accommodate solder balls and other coupling elements for signal and power interconnects

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The EBG structure is applied selectively in specific locations where surface wave suppression is most needed, rather than uniformly across the entire surface. This localized approach allows coupling elements to be placed in areas where EBG structures are absent, reconciling manufacturing requirements with electromagnetic performance

Inventive Principle:

Principle #3Local quality

3Object-generated harmful factors

If reflector is arranged at distance from antenna element on PCB layer, then parasitic radiation is reduced, but ripples are caused in radiation pattern

Engineering Contradiction:

Improveparasitic radiationVSAvoidradiation pattern uniformity

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The EBG structure serves as an intermediary between the antenna element and the PCB reflector, suppressing surface waves that would otherwise cause ripples in the radiation pattern. This mediator component allows the reflector to remain at an effective distance while eliminating the harmful ripple effects

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful surface waves that propagate between the antenna and reflector into beneficial suppressed modes through the EBG structure. The periodic pattern of the EBG creates band-gap frequencies that prevent surface wave propagation, turning a harmful electromagnetic phenomenon into a controlled and beneficial suppression effect

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 EBG structure effectively reduces side lobes and distortions in radiation patterns, enhances antenna gain, and allows for better control of beam width, improving the performance of microwave antennas by suppressing surface waves and increasing flexibility in antenna design for mm-wave applications.

Implementation Method 1

an electromagnetic band gap structure, EBG, module coupled to the redistribution layer of the package module

Methodology Applied

Scientific EffectElectromagnetic band gap structure:

Data Source

PatentUS11350522B2Microwave antenna apparatus

Publication Date: 2022.05.31 SONY GROUP CORP

AI summary

A microwave antenna apparatus comprises a package module comprising a semiconductor unit, an antenna unit arranged on a first side of the package module and a redistribution layer group arranged on a second side of the package module opposite the first side, and an electromagnetic band gap structure, EBG, module coupled to the redistribution layer group of the package module.