A Shared-Aperture Dual-Band Array Antenna Using Gap Waveguide Technology

In this letter, a 2×2 shared-aperture dual-band array antenna is presented, which utilizes gap waveguide technology to achieve wide bandwidth. The proposed dual-band radiating element consists of two layers of open radiating cavities and a metal cover plate. The cavities are designed as hexagonal structures of different sizes. The lower and upper radiating cavities operate in X-band and Ku-band, respectively. The upper cavity is placed orthogonally relative to the lower cavity for generating different line polarizations and improving the isolation between them. Each cavity is fed by a separate groove gap waveguide. An array is formed and simulated using the proposed dual-band radiating elements. The simulation results show that the -10.0 dB impedance bandwidth of the proposed antenna are 9.8-11.0 GHz in X-band and 14.7-19.0 GHz in Ku-band, respectively. The realized gains are 14.7 dBi (at 10.0 GHz) and 16.7 dBi (at 15.5 GHz) in two different polarizations.