On the Fresnel Approximation

《On the Fresnel Approximation》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、1958BurmrurdWilcox:OntheFresnelApproa5mation43latedsectioncontainsotherelectricaldevicessuchasACKNOWLEDGMENTnavigationlightsorhigherfrequencyantennas.TheyTheauthoracknowledgeswithgratitudehisdebttoalsoavoidthenecessityforspeciallightningprotectionDr.J.V.N.Grangerwhoseenduringin

2、terestinaircraftmeasuresrequiredwithcap-typeantennas.Acharacter-antennasystemshasprovidedmuchofthemotivationisticofbothshuntandnotchantennasthatmaybeafortheinvestigationreportedhere,andtoDr.J.T.significantadvantage,althoughitposesspecialprob-Bolljahnformanyhelpfultechnicaldiscu

3、ssions.Heislemsinthedesignofantennacouplerstomatchthem,isalsoindebtedtoA.V.McKenziewhocarriedoutmostthefactthattheirimpedancelevelsarerelativelylow.ofthenumerousmeasurementsandtoDr.JackClineThismeansthatvoltagebreakdownoftheantennasfordiscussionsregardingmultipleturncouplingini

4、snotaseriousproblemevenwithhighradiatedpowers.hotches.OntheFresnelApproximation*R.B.BARRARTANDC.H.WECOX$Summary-ThepurposeofthispaperistoshowthepowerofthecanbereducedtotabulatedFresnelintegrals.Thepur-SommerfeldexpansionincomputingFresnelandnearfieldsofan-poseofthispaperistopoi

5、ntoutthattheSommerfeldtennas,amatterwhichhasbecomeofincreasingimportanceinhighexpansionisapromisingmethodofcomputingtheseresolutionantennas.AconnectionisshownbetweentheFresnelandnearandFresnelfields.FraunhoferapproximationsforradiationfieldswhichisderivedbyusingSommerfeld’sexpa

6、nsionofthefieldininversepowersofradialTHESOMMERFELDEXPANSIONdistance.ThisexpansionpermitsanestimateoftheerrorincurredinusingtheFresnelapproximation.Higher-ordercorrectionstotheAlthoughinsphericalcoordinatesasolutionofthephaseandamplitudeportionoftheFresnelapproximationarealsosc

7、alarwaveequationexhibited.BywayofillustratingthepoweroftheSommerfeldex-pansionofthefieldsintheFresnel(intermediate)regionofaradia-V?U+p1:=0(1)tionsource,numericalcalculationsofamplitude,phase,andpowerpatternshavebeenmadeforahitelinesourceoflengthDwithanisusuallygivenintermsofan

8、infiniteseriesinvolvingequiphasecosine-on-a-pedestalcu