Paper presentation – Ultra-Portable Devices Outline • Introduction Paper: Paper: • Why DRA • Types of DRA elements A. Petosa, A. Ittipiboon, Y.M.M. Antar, D. Roscoe and M. Cuhaci ” R ” Recent Advances in Dielectric Resonator Antenna t Ad i Di l t i R t A t • Array configuration Technology ” • Summary IEEE Antennas and Propagation Magazine, Vol. 40, No. 3, June 1998 Presented by: Rohit Chandra 2010-01-26 Paper Presentation - Ultra Portable Devices 1 2010-01-26 Paper Presentation - Ultra Portable Devices 2 Introduction What is DRA • Is DRA alternative to traditional Antenna? • Resonant antenna fabricated from low-loss microwave dielectric material. di l t i t i l • Resonant frequency: function of size, shape, and ε r • Past work done to characterize basic properties of DRA for variety of simple shapes and feed configuration • Coupling through slot, probe, aperture • Recent development: novel DRA elements to enhance BW and gain; active DRA using ferrite materials; compact and low • Impedance BW function of ε r and profile DRAs profile DRAs dimensions ( eg. aspect ratio ) • BW upto 10% easily achievable for rectangular DRAs with ε r < = 10 2010-01-26 Paper Presentation - Ultra Portable Devices 3 2010-01-26 Paper Presentation - Ultra Portable Devices 4
Return Loss And Pattern for Why DRA rectangular DRA rectangular 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 ε r ( 6-100): Control over size and BW ( wide BW: low ε r , compact size: high ε r ) • Low/No tolerance errors • Enhancing techniques for MPA equally applicable for DRA Types of DRA element Wideband DRA • Wide band DRA • Notched rectangular DRA - slot fed • Compact - notch decreases radiation Q factor � increases BW • Circular Polarized - Dimension of Notch can be adjusted for Dual Mode or wideband operations . • High Gain • Active
Wideband DRA Wideband DRA • Multi-segment DRA M lti t DRA • Parasitic DRAs P iti DRA - Strong Coupling: High ε r -Same technique as used in MPA - Wide bandwidth: Low ε r -Parasitic DRA resonates as different frequency - To Resolve : High ε r inserted below g r Low ε r for matching impedance of DRA -Combined effect produces wideband individual BW:5.8%, combined:17% - BW � 20 % -Single Feed, No matching Network, multiband operation also possible Compact DRA Circular Polarization • Frequency half � Volume increment 8 times F h lf � V l i t 8 ti • Complexity in design of CP radiation • Increase ε r � BW decreases • two point feed: equal amplitude in phase quadrature required power divider: increase in insertion loss i d di id i i i i l • Solution : Placing Short-circuit at point of symmetry in E-fields • single feed: redesigning MPA’s patch for •Some decrease in BW but can be increased by MSDRA •Some decrease in BW but can be increased by MSDRA d dual-orthogonal modes � produces Narrow BW ( 1-2 %) l th l d � d N 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 Planar Arrays •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
Summary • DRAs can be used as an alternative to traditional antennas for several cases • Flexibility in design • Compact and low cost
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