A low-frequency hybrid folded dipole UAV-mounted GPR antenna

A hybrid folded dipole patch antenna (HFDPA) composed of linear folded dipole and bow-tie dipole is proposed. By bending the tail linear radiation conductor with relatively small distributed current at the antenna and loading the dielectric onto the antenna, the gain at the low-frequency end of this antenna can still approach the gain of a standard half-wave antenna even after the physical length is significantly reduced. Meanwhile an efficient resistive loading implement method of “broadband loading, local optimization (BLLO)” is proposed based on the classical Wu-King loading theory. The size of the finished antenna is 1800 mm × 200 mm × 1 mm and the minimum operating frequency is 20 MHz. The antenna simulation and test results prove that the antenna has a low-frequency gain close to the standard half-wave antenna, and there is no obvious ringing effect.