UWB antenna array

This paper compares the performances of ultra wideband (UWB) arrays that use sinusoidal waveform for power pattern and ultra-short pulse waveform for energy pattern. In general, antenna arrays cannot have element spacing larger than one wavelength in any plane because the resulting grating lobes absorb much power, which will limit the bandwidth of antenna arrays. In particular, there are substantial differences between power pattern and energy pattern for UWB arrays. The grating lobes of UWB antenna array will not occur at the energy pattern even if the element spacing of array is larger than one wavelength. The limited antenna power patterns in frequency domain are used to describe the antenna performance. The energy pattern of antenna is the total response of power patterns in frequency domain. Energy pattern are quite similar to that of power pattern for narrow band antennas. It is enough to describe the antenna performance in narrow band communication systems. However, the limited antenna power patterns in frequency domain are not enough for UWB arrays in communication systems. Energy pattern will be easier to describe the energy pattern instead of power pattern for UWB arrays. In order to verify the theory of antenna pattern in energy, numerical simulations of UWB arrays with different element spacing are demonstrated the significance of these parameters and measured by the impulse time domain radar system. These results are of particular importance to the emerging technology of base band or time domain communications and remote sensing.