Wide‐band CPW‐fed slot antenna with parasitic directors for end‐fire radiation

In this study a novel slot array antenna backed by a metallic reflector has been presented which produces end-fire radiation. Several slots with different dimensions were etched in the ground plane of a thin substrate. Only first two slots were fed directly by a coplanar waveguide feed line while the other slots radiate by the mechanism of parasitic coupling. The simulation results show that the proposed antenna is capable of producing tilted end-fire beam in a wide frequency band ranging from 12 to 18 GHz. The fractional impedance bandwidth of the antenna was found to be 40%. A prototype of the design was also fabricated and measurements were taken. It was found that the simulated results for the return loss, radiation pattern and gain of the antenna are close to the measured ones. The peak measured gain was found to be 10 dB while the maximum gain in exact end-fire direction is almost 2 dB. As the radiating elements are slots therefore the antenna can be flush mounted in the conducting surface of an airborne vehicle. Moreover, due to the small thickness of substrate the antenna can be easily designed for conformal applications.