Enhanced radiation gain and efficiency of a metamaterial-inspired wideband microstrip antenna using substrate integrated waveguide technology for sub-6 GHz wireless communication systems

This paper shows a technique to enhance the radiation gain and efficiency of metamaterial (MTM) inspired planar antenna using substrate integrated waveguide (SIW) technology for sub-6 GHz wireless communication systems. The antenna consists of MTM unit-cells comprising series interdigital-capacitor and short-circuited spiral stub. The proposed antenna behaves like a leaky wave antenna. In the transmission mode the input signal propagating along the antenna structure and leaks energy. The performance of the antenna is shown to enhance by embedding a column of metallic vial between the MTM unit-cells. This technique has no impact on the size of the antenna. The antenna was constructed on a standard FR4 dielectric substate. It had dimensions of 23.2x6.4x0.8 mm(3) and had a wide operational frequency range 1.8 GHz from 3.0-4.8 GHz. After applying SIW the average gain and efficiency of the antenna were 5.8 dBi and 78%, respectively, which is an improvement of 2 dBi and 21% across 3-4.8 GHz.