Fabry-Perot Cavity Antenna for Tri-Band Array Environment with Radome

A multi-layer Fabry-Perot cavity antenna (FPCA) for increased boresight directivity is proposed for a high-band (HB) (3.4 – 4.2 GHz) array in a tri-band array environment with dielectric radome. Upon excitation of the HB dipoles in the baseline design, the radome behaves as a partially reflecting surface (PRS) which introduces reflected waves that destructively interfere with the incident wave at boresight at 4.1 GHz and 4.2 GHz. The superposition of these waves results in unacceptable boresight attenuation, leading to a reduction in the boresight directivity. The proposed FPCA reduces the boresight attenuation at 4.1 GHz and 4.2 GHz, thereby increasing the boresight directivity. The proposed technique shows a peak improvement in boresight directivity at 4.2 GHz from 10.3 dBi to 14.0 dBi, a 3.7 dB improvement, and a reduction in cross-polar radiation.