Design of an Array of Patch-elements With a Band-pass Frequency Selective Surface Hybrid Radome : Analysis and characterisation of a frequency selective surface and a phased array antenna

Abstract: A circular polarised phased array antenna and a frequency selective hybrid radome are designed and evaluated. The antenna system is well suited as a part of a communication link between platforms with a 600 MHz bandwidth and a centre frequency of 5 GHz. A prototype consisting of 8 x 8 patch elements has been designed, manufactured and characterised. The final configuration will be a compact, relatively inexpensive system with single-fed antenna elements. An array antenna with circular polarisation is suitable when the receiver must maintain a strong signal regardless of the relative antenna orientation. The radome protects the antenna and can also reduce both the radar cross section and interference from out-of-band signals. The main focus is to make sure that the phased array antenna and the radome work as one unit and maximise the field of view in which the polarisation is circular. The method to maximise the field of view is to reduce the coupling between antenna elements by using shorting via fences surrounding each element. Following this method results in a total array gain of 18 dBi, 25° half-power beamwidth and a ±35° maximum scan angle with maintained circular polarisation. Prototype measurements agree well with the simulated results.