Optimum Focal Point of a Paraboloidal Reflector Antenna With an Omnidirectional Radiative Source

A paraboloidal reflector antenna is useful for enhancing the directivity of a feed antenna with a low directivity. In this letter, we investigate a paraboloidal reflector antenna that has an ultrawideband (UWB) omnidirectional radiative source as the focal feed. To obtain the optimized focal length f for a given diameter D of the paraboloidal reflector antenna, we employ a simple relation between f and D, which can reduce the spreading loss of the source field while maintaining the aperture field uniformity. Simulation results show that the f values obtained from the above relation can maximize the far voltage-a well-known figure of merit for UWB applications.