UWB Antenna Surrogate Design

Abstract

Ultra Wide Band (UWB) antenna systems have a wide variety of uses including impulse radiation for communication, material property determination, structural feature viewing in building trades, buried object detection and other uses. In each case, the UWB nature (significant frequency content from kHz through multi-GHz) of the overall system combined with the nearand mid-field aspects of the operation present unique challenges. Previous EMP/HEMP work where far-field approximations apply and objects are significantly shielded [1] may not be applicable [2]. Often very little or no shielding is present with complex structures (Figure 7) invalidating cavity/perturbational approximations [3] and the antenna systems are often near, mid and far-field within the same time-domain impulse drive due to the UWB nature thereby invalidating far-field approximations [4]. Major sub-systems for a successful UWB system design include the radiating antenna, the power supply, the power source and the near-field structural environment. In the process of developing a production system, a “closed-loop” process of physical testing and analysis, combined with modeling and simulations, provides a more complete perspective on the operational aspects permitting significant optimizations in a cost-effective manner. Lengthy physical testing, as well as manufacturing multiple full-scale test antenna systems, can be time-consuming and cost prohibitive. In other situations, creating a complete full-scale mockup of the antenna system may not be possible due to cost constraints. In a study of capabilities, an antenna system may not initially be available for physical testing. In each case, creating a suitable surrogate for preliminary physical testing and simulations is advantageous. [2]