Outline Introduction Paper: Paper: Why DRA Types of DRA - - PowerPoint PPT Presentation

Paper presentation – Ultra-Portable Devices

Paper: Paper:

• A. Petosa, A. Ittipiboon, Y.M.M. Antar, D. Roscoe and M. Cuhaci

”R t Ad i Di l t i R t A t ”Recent Advances in Dielectric Resonator Antenna Technology” IEEE Antennas and Propagation Magazine, Vol. 40, No. 3, June 1998

Presented by:

Rohit Chandra

2010-01-26 1 Paper Presentation - Ultra Portable Devices

Outline

• Introduction
• Why DRA
• Types of DRA elements
• Array configuration
• Summary

2010-01-26 2 Paper Presentation - Ultra Portable Devices

Introduction

• Is DRA alternative to traditional Antenna?
• Past work done to characterize basic properties of DRA for

variety of simple shapes and feed configuration

• Recent development: novel DRA elements to enhance BW

and gain; active DRA using ferrite materials; compact and low profile DRAs profile DRAs

2010-01-26 3 Paper Presentation - Ultra Portable Devices

What is DRA

• Resonant antenna fabricated from low-loss microwave

di l t i t i l dielectric material.

• Resonant frequency: function of size, shape, and εr
• Coupling through slot, probe, aperture
• Impedance BW function of εr and

dimensions ( eg. aspect ratio )

• BW upto 10% easily achievable for

rectangular DRAs with εr < = 10

2010-01-26 4 Paper Presentation - Ultra Portable Devices

Return Loss And Pattern for rectangular DRA rectangular DRA Why DRA

• Radiation Efficiency > 95%
• Various shapes: flexibility in design
• Several feeding mechanisms: capable to integrate with various technologies
• Various modes producing broadside or conical pattern
• Various modes producing broadside or conical pattern
• Wide range of εr ( 6-100): Control over size and BW ( wide BW: low εr , compact

size: high εr )

• Low/No tolerance errors
• Enhancing techniques for MPA equally applicable for DRA

Types of DRA element

• Wide band DRA
• Compact
• Circular Polarized
• High Gain
• Active

Wideband DRA

• Notched rectangular DRA
• slot fed
• notch decreases radiation

Q factor increases BW

• Dimension of Notch can be

adjusted for Dual Mode or wideband operations.

Wideband DRA

M lti t DRA

• Multi-segment DRA
• Strong Coupling: High εr
• Wide bandwidth: Low εr
• To Resolve : High εr inserted below

g

r

Low εr for matching impedance of DRA

• BW 20 %

Wideband DRA

P iti DRA

• Parasitic DRAs
• Same technique as used in MPA
• Parasitic DRA resonates as different

frequency

• Combined effect produces wideband

individual BW:5.8%, combined:17%

• Single Feed, No matching Network,

multiband operation also possible

Compact DRA

F h lf V l i t 8 ti

• Frequency half Volume increment 8 times
• Increase εr BW decreases
• Solution : Placing Short-circuit at point of symmetry in E-fields
• Some decrease in BW but can be increased by MSDRA
• Some decrease in BW but can be increased by MSDRA

Circular Polarization

• Complexity in design of CP radiation
• two point feed: equal amplitude in phase quadrature

i d di id i i i i l required power divider: increase in insertion loss

• single feed: redesigning MPA’s patch for

d l th l d

• d

N BW ( 1 2 %) dual-orthogonal modes produces Narrow BW ( 1-2 %)

• For DRA single feed upto 7% BW

High Gain DRA Active DRAs :FRAs

• When unbiased: FRAs similar to DRAs
• Biasing: parameters can be controlled electronically:

can shift frequency either above or below depending q y p g upon direction of bias field

Array Configuration

• Series fed array
• Series fed array

Disadvantage:

• can’t be used for wide-band fixed beam

can t be used for wide band fixed beam applications

• small amount of coupling b/w microstrip and

p g p DRA Solution ( in same space constraint):

• branch line feed
• MSDRAs

Planar Arrays

Summary

• DRAs can be used as an alternative to traditional antennas for

several cases

• Flexibility in design
• Compact and low cost