Special issue: Waveform diversity: part II

It is our great pleasure and honor to introduce the second of two special issues of the IEEE Aerospace and Electronic Systems Magazine on Waveform Diversity. The first paper,"Application of Waveform Weighting for a Frequency-Invariant Transmit Beampattern,"by Uysal et al. discusses a proposed method for implementing wideband beamforming in wideband active-array systems where precise beampatterns are desired. The authors use their beamforming method to design and synthesize a multi-channel set of waveforms that enables wideband beamforming while achieving a frequency-invariant beampattern with low sidelobes. In combination with digital predistortion, the weighted beamforming method has yielded effective results for LFM and P4 polyphasecoded waveforms in simulations and hardware measurements. Consequently, the authors feel that their wideband beamforming method has potential application in any wideband active array system when a precise beampattern is desired.