Radar Waveform Design for Spectrum Sharing using the Antenna Fidelity Pattern

Abstract

Spectrum is a precious and a extremely limited resource. New technology and innovations are giving rise to novel and diverse wireless systems. Unfortunately, as these systems come to fruition worldwide, the already crowded spectrum becomes even more congested due to the high-speed data links offered by systems like LTE, 4G and 5G as well as a profusion of new technologies, such as IOT attempting to cohabitate with increasingly complex radars. There is increasing pressure to find ways to better share spectrum among communications and radar systems. Better interoperation between systems requires a more holistic solution that takes into account frequency, time and space as well as any unintended hardware distortion effects. Distortion effects of antennas and arrays that are often overlooked are examined in this paper. The specific distortion effects of a slotted waveguide array are examined by using Ultra Wideband (UWB) antenna characterization techniques that are useful even for non-UWB antennas. This approach shows that angle dependent antenna distortions can present significant challenges to applying waveform diversity to spectrum engineering as the performance of spectrum optimized waveforms will be compromised at off-boresight angles for radars or other systems.