W-band compact slot antenna arrays with polarization flexibility

A novel W-band arbitrary polarization compact radiating structure that can be used to design antenna arrays with wide angle beamforming and limited grating lobes is described in this article. The radiating element is a slot which can be oriented in any direction to achieve the desired polarization. This slot is placed on a rectangular cavity, which is operated in its fundamental mode to achieve compact size. The cavity is coupled with a substrate-integrated waveguide feed line using a coupling slot. These radiating elements are series fed to form compact one-dimensional arrays, which can be combined to design two-dimensional arrays having field of view up to 120° and with limited grating lobes in the plane transverse to the one-dimensional array axis. One- and two-dimensional arrays for two orthogonal polarizations were fabricated and tested to validate the described structure.