Increasing the EIRP by using FPA-fed reflector antennas

The wireless communication range of E-Band point-to-point antenna systems can be extended by increasing the effective isotropic radiated power (EIRP). By employing a focal plane arrays (FPA), the reflector antenna can generate a high EIRP with electronic beam steering. By axially displacing the FPA towards the reflector, the field pattern across the FPA will be broader. Therefore the number of active elements in the array is increased, resulting in a higher EIRP. An in-house developed FPA model based on the physical optics (PO) surface current method is used in this analysis. It is found that 8 dB can be gained if the FPA with 9 × 9 active array elements is axially displaced by 2.3 λ (Frequency 71 GHz) towards the reflector. For this axial displacement the tapering and spillover efficiency are maximally reduced by 3 %. A higher EIRP can be achieved by increasing the axial displacements, but in this case, the FPA size must be increased in order to meet efficiency criterion of 80 %.