radiation quality factor
M.S. Miloserdov, A.I. Gigolo
Now, actively develop multifunction airborne, which combine some independent systems on one antennas array, such as communication, radiolocation, telemetry, guidance, electronic warfare and counter systems, state recognition and air traffic control systems. This approach can significantly reduced weight and size performance of antenna array. However, required to solve some tasks, such as wideband antenna array and powerful amplifier developing and some system questions of work different systems on one antenna array. Besides, actual a placing problem and make hard demands to weight and size of on-board antenna array.
In the paper considered three methods to reduce of log-periodic dipole antenna (LPDA) size: put LPDA in dielectric symmetric layer, use meander shape dipole of log-periodic antenna, put LPDA in U-shape open resonator. First method can reduce antenna size up to 30..40% if using dielectric with hide permittivity. However, this approach leading to hide reflection from boundary with open space. The meander shape LPDA dipoles reduce antenna size up to 10..15%. Using U-shape open resonator in LPDA construction to reduce antenna size up to 50..60% and significantly near to theoretical limit of antenna dimension in a given band.