Hibrit frekans seçici yüzey (FSY) radom tasarım, üretim ve ölçümü

In modern military platforms such as ships, aircrafts and missiles, frequencyselective surfaces (FSS) are widely used for antennas and radar cross section(RCS) reduction. The RCS of complicated objects such as antennas are difficultor impossible to control over a wide frequency range. The most efficient andcost-effective approach in these situations is to shield the scattering object fromthe threat radars by making use of wide-band radar absorbing material (RAM)coating. If the object is an antenna, then obviously, the system served by thisantenna cannot operate when it is stowed. An alternate approach is to cover theantenna with an FSS that is transparent at the antenna operating frequency, yetopaque at the threat radar frequencies.In this thesis, different types of FSS structures comprising slot elements andmodified loop elements, namely single polarized loop FSS, have been investigatedintensively with their applications to hybrid FSS radomes. Their resonancemechanisms and transmission properties are examined in detail. The mainfocus of the thesis is to design a hybrid FSS radome based on different unitelement types. Complex dielectric constant measurements are conducted as aninput to the FSS radome design. Experimental results based on measuring thetransmission curves of fabricated radome prototypes are supported by computersimulations. Transmission properties of the slot FSS structures and the singlepolarized loop FSS structures have been compared and discussed. In contrastwith most of the published work in literature, transmission measurements aresupported by the radiation performance measurements. Adaptation of the singlepolarized loop FSS radome to the slotted waveguide antenna has been achievedwithout any significant reduction in the radiation performance. The antennawith this metallic radome has the advantage of superior mechanical durabilityas well as reduced out-of-band RCS.