A study on an onboard Ka-band phased-array-fed imaging reflector antenna

We proposed a new method for reducing the grating lobe level even when the number of radiating elements in the imaging reflector antenna is small. The most significant feature of this method is that the distance between the array plane and the center of subreflector is controlled so as to reduce the generated grating lobes. Using this method the magnification factor M can exceed the usually used value in order to decrease the number of radiating elements. This method is extremely low-cost because no additional components are added, and it does not decrease the reliability. An onboard phased-array-fed imaging reflector antenna was designed for the future Japanese Ka-band broadband satellite communication system by using the proposed method, and its performance met the system requirements.