T-Pulse for Exciting Single Modes of Radar Targets

We present an approach called T-pulse approach to excite a single mode of a target. The T-pulse is a time-limited signal that has maximum energy in a given frequency band. While the T-pulse method can be applied to any highly resonant target for the purpose of target iden­ tification and discrimination, an application of the T-pulse method to a synthesized thin-wire target is presented to illustrate its ability of exciting single modes. I. INTRODUCTION In this paper, we present the T-pulse approach, which deals with an op­ timal time-limited and band-pass EM pulse to excite a target. The resulting response is a preselected single mode scattered response from the target which may be used for the purpose of target identification and discrimination (TID). From the target discrimination point of view, a preselected target may have a mode which is singularly differ­ ent from all other modes of different targets under consideration. If the T-pulse is tuned to a preselected mode and is applied to a target, the desired single mode response is obtained. In the T-pulse approach, we synthesize the exciting T-pulse basically by tuning the center frequency of the T-pulse according to the resonant frequencies of a .d~~ired tar_get. Some approaches ( 1-4) for radar target id.eritificatiqn .requires using an EM pulse to excite a target and then retrieving many aspect­ independent poles of the target from scattered field. There are two extreme cases for this approach. The first extreme case is that an impulse, or wide-band, signal is used to excite the target, and all the poles (or modes) in the impulse response are estimated. Ideally, this approach is very fast in the sense that "all" poles of the target are obtained together in a short period of time. However, the accuracy of This work has been supported in part by Aeritalia Corporation and by the Office of Naval Research under contract N00014-79-C-0598.