Electromagnetic compatibility (EMC) measurements for the 1 - 18 GHz band are extensively performed using the Double-ridged guide horn antenna (DRGH).
Several attempts documented in literature have aimed to achieve this bandwidth, while considering input match and radiation pattern behavior which define UWB operation. Historically however, designs usually suffered from pattern degradation above 12 GHz, where the pattern splits up into four lobes, instead of maintaining a single main lobe [Bruns et al.], and the boresight gain reduces by approximately 6 dB. [Jacobs et al.]
This antenna covers the full 18:1 bandwidth needed for EMC measurements, both in terms of input match and radiation pattern [Jacobs et al.].Typical total gain patterns at (a) fmin, (b) 8fmin and (c) 18fmin... Typical gain versus normalised frequency Typical S11 versus normalized frequency
B. Jacobs, J. W. Odendaal, and J. Joubert, 'An Improved Design for a 1-18 GHz Double-Ridged Guide Horn Antenna', IEEE Transactions on Antennas and Propagation, vol. 60, no. 9, pp. 4110-4118, Sep. 2012.
C. Bruns, P. Leuchtmann, and R. Vahldieck, 'Analysis and Simulation of a 1-18GHz Broadband Double-Ridged Horn Antenna,' IEEE Transactions on Electromagnetic Compatibility, vol. 45, no. 1, February 2003, pp 55-60.