1 www.cst.comCST UGM 2009UWB Antenne Simulation withCST MICROWAVE STUDIODesign from: A novel tapered slot CPW-fed antenna for ultra-wideband applications and its on/off-body performance. Atiqur Rahman, Yang Hao, Member IEEEDepartment of Electronic Engineering, Queen Mary, University of London IWAT 2007Dr. Frank Demming-Janssen2 www.cst.comOutline UWB Basics UWB-Antenna Characterization CST MWS Feature Overview for UWB Antennas/Online Demo Question/Discussion3 www.cst.comUWB Basics Pulse communication: no carrier frequency Pulse spectrum of UWB transmissions pulse in the range from 3.1 GHz to 10.6 GHz UWB is aimed at high data rates for personal-area networksMain challenge for Antenna : UWB characteristic of return loss- simulation possible with any 3D Field Solver (FD, TD, MoM) Ability to preserve the pulse shape of the transmitted signal in the Farfield- Natural Solver Choice: TD Solvers!S-ParameterExcitation Pulse and Farfield signal4 www.cst.comSpecialty of UWB Antennas Broadband antenna design is often based on frequency independent antennas These antennas work well for multi band applications but perform badly for UWB because of pulse distortionLog Spiral Antenna S-ParameterInput pulse at port Pulse shape in Farfield5 www.cst.comUWB-Antenna Characterization Characterization of the UWB Antenna performance by Group delay of the transmitted signal Direct comparison of excitation and transmitted signal (signal cross-correlation) Group delay is a measure of the transit time of a signal through a device versus frequency. The variations in group delay cause signal distortion. Const. group delay -> perfect signal transmission= - delaygroup The cross-correlation is a measure of similarity of two waveforms as a function of a time-lag applied to one of them. Cross-Correlation of 1 -> perfect signal transmission( ) ( ) d t g f + = n correlatio - cross6 www.cst.comExtraction of Group Delay and Cross-CorrelationGroup delay and Cross Correlation are secondary data and can be extracted using the template based post processing features in CST MWS-> Online Demo (later)7 www.cst.comFeatures Overview for UWB Antennas Arbitrary time signals- Gauss Derivatives- 1st, 2nd.. order Rayleigh- User Defined- Tabulated Values- Transient Pulse from Circuit Simulation Time Domain Monitoring- Broadband Farfield Monitor - Farfield Probe Response Advanced Signal Processing of Time and Frequency Response including optimization of processed signals- Power Spectrum Density- Correlation- Standard Operations (DFTs, FFTs)8 www.cst.comChoice of excitation signalSignal LibraryVBA scripting of arbitrary time functionsTabulated values9 www.cst.comTime Domain ResultsPort Signal ResponseExcitation and Reflected SignalPower Spectrum Density of Excitation Signal10 www.cst.comTime Domain ResultsBroadband Farfield MonitorFarfield Frequency Domain ResponseFarfield Time Response11 www.cst.comTime Domain ResultsTime Domain FieldsSurface CurrentsE/H Fields12 www.cst.comTime Domain ResultsFarfield Pulse ResponsePulse Response at arbitrary farfield position13 www.cst.comAdvance Signal ProcessingSignal ProcessingList can be extended by user specify operations14 www.cst.comSelect post processing stepAdvance Signal ProcessingCross-Correlation FunctionLoad Port and Probe SignalTime DelayMax. Correlation15 www.cst.comUWB Performance of Log SpiralCross Correlation- no main peak -Farfield Group Delay- large runtime difference -16 www.cst.comSurface Currents At low frequency, the full antenna length is used.17 www.cst.comFarfield18 www.cst.comUWB Antenna Test VehicleOnline DemoDesign from: A novel tapered slot CPW-fed antenna for ultra-wideband applications and its on/off-body performance. Atiqur Rahman, Yang Hao, Member IEEEDepartment of Electronic Engineering, Queen Mary, University of London IWAT 200719 www.cst.comBroadband S-ParameterComparison FD Solver TD SolverClose match20 www.cst.comUWB Performance of Tapered Slot CPW AntennaCross Correlationsingle main peakFarfield Group Delayalmost flat response21 www.cst.comDesign VariationsConformal UWB AntennaEasy conformal modeling with special bending feature22 www.cst.comDesign VariationsConformal UWB AntennaS-ParameterCross Correlation23 www.cst.comDesign VariationsNear and Farfield Results24 www.cst.comThank you