Ultra-compact end-loaded planar dipole antenna for ultra-wideband radar and communication applications
A planar dipole antenna is loaded with LC-tank resonators and chip resistors presented for ultra-wideband (UWB) radar and communication systems. Each staircase rectangular arm of the proposed planar dipole is loaded with an open complementary double concentric split-hexagonal-ring resonator (LC-tank) and a pair of chip resistors at the end for bandwidth enhancement, whereas a broadband microstrip to parallel-plate transformer (or balun) is applied as the feeding structure of the antenna to provide impedance matching as well as balanced–unbalanced transition. The measurement results show that the proposed antenna operates over a frequency bandwidth of 0.64–3.8 GHz with S 11 < −15 dB and exhibits highly directive radiation patterns for the first 100% of the operating bandwidth (0.64–2 GHz) with gains in the range 2.2–4.2 dBi.
