Frequency invariant far-field beam pattern of UWB printed circular monopole antenna array

This paper applies the concept of the frequency invariant far-field beam pattern to a printed linear UWB antenna array. The theory of the broadband frequency invariant far field sensor from the field of acoustics is adopted and applied to a discrete UWB printed circular monopole antenna array (PCMAA) for the frequency range from 3.1 to 10. 6 GHz. Low pass filters (LPF) are employed to feed the individual elements of the PCMAA in order to establish an array of frequency invariant electrical width. Although the array design deviates from the ideal design by using uniform element spacing, the full wave simulation and the measurement verify that the variation of the beamwidth across the frequency range can be suppressed by filtering the PCMAA element excitation with a set of LPF.