Ultrawide-Band Antenna Distortion Characterization Using Hermite-Gauss Signal Subspaces

Evaluation of signal distortion produced by antennas in ultrawide-band (UWB) communications has become an important concern due to possible degradation in signal-to-noise ratio (SNR) and furthermore, in system bit-error rate (BER). Fidelity has proved to be a useful method for taking into account distortion involving single-users and single waveforms, that is, unidimensional signal spaces. A new method for evaluating distortion in multiple waveform sets is set forth in this letter. The method is based on a link representation matrix computed by means of Hermite-Gauss signal subspaces and a related Frobenius matrix norm. Proof that this measure allows evaluation of distortion by resorting to a geometrical approach is supplied. Finally, its properties and applications are analyzed, highlighting its differences, advantages, and drawbacks in comparison with the traditional method.