DESIGN OF A HIGH-GAIN ULTRAWIDEBAND PLANAR DIPOLE ANTENNA USING LC TANKS, CHIP RESISTORS, AND DUAL-LAYER FREQUENCY SELECTIVE SURFACE

摘要

In this article, a low-profile, high-gain, ultra-wideband (UWB) planar dipole antenna is presented for radar imaging applications. The antenna is loaded with open complementary double concentric split-hexagonal-ring resonators (LC tank) and chip resistors, and backed with a novel double-layer frequency selective surface reflector for gain enhancement. A broadband microstrip to parallel-plate transformer is designed as the feeding structure of the antenna to provide impedance matching and balanced-to-unbalanced transition. The measurement results show the proposed antenna operates over the frequency bandwidth of 0.65-3.8 GHz with S_(11) < -10 dB (VSWR) and smooth gains in the range of 6.2-9 dBi.