Inverted T-Slot Compact Microstrip Antennas for Multiband Operations

In the days of modern communication, the compact size, low profile antenna with the directional capability is demanded for the wireless communication applications. To fulfill this requirement two new structures of antennas are designed. Two different geometries of microstrip antenna for triple band and Tetra band operation have been investigated in this paper with a new concept of T-slot in the radiating element of antenna and an E-slot in the ground plan of the antenna. For the wideband operation the partial ground with E-slot is used.The designed structure can be use for the multiband operation with the directional radiation pattern and the return loss of the antenna is below -10 dB. The resonant frequency band shown by the first structure is centered at the 3.4 GHz, 7.4 GHz and 10.6 GHz. One frequency band is increased by changing the ground parameter of the first structure thus second structure works at the four frequency bands which are centered at the 4.4 GHz, 5.3 GHz, 8.6 GHz and 11.2 GHz with improving results of the antenna. These antennas, proposed and modified structure have small size of 22 X 16 X 1 mm with the ground plane. For designing of these structure FR-4 substrate of thickness h = 1 mm with Dielectric constant = 4.05 and loss tangent of the antenna is 0.02 is used. CST microwave studio software is used for the simulation of the designed structures.