Wide-band conversion of donut-shaped pattern to directive one by square-shaped pattern director antenna

In this paper, an antenna with 8 GHz (7–15 GHz) bandwidth is designed, simulated, fabricated, and measured. Commonly, for the effective use of electromagnetic sources, mode converters are used to transform donut-shaped patterns to directive patterns. This paper introduces a novel antenna called the pattern director antenna (PDA) that solves most problems associated with the azimuthally symmetric output modes of high-power microwave sources. The PDA accepts directly (without the need for mode conversion) an azimuthally symmetric generated mode of an electromagnetic source and converts it to radiate a directive pattern. For the proof of concept and validation of the design by simulations, the 3D printing technology [using polylactic acid (PLA)] is used to fabricate the PDA and measure its radiation patterns and return loss. The selected material is cheap and also environmentally friendly. The antenna was coated with aluminum to become a conductor. The gain is from 16.8 to 21.8 dB in the frequency range. The S11, main lobe deviation (MLD), and sidelobe level (SLL) are less than −15 dB, 2°, and −7 dB, in all frequency range, respectively. The simulation results are in good agreement with the measurement.