Study of multi-band and ultra-wide band antennas (6-8.5 GHz)

Abstract: Since the United Sate Federal Communication Commission (FCC) released the first Ultra Wide-band (UWB) report on February 14, 2002, the interest in UWB technology has increased substantially in both academia and industry. Interest is to simulate by the expectation that UWB can solve the shortage of the available frequency recourses. The European Electronics Communications Committee (ECC) has approved the use of UWB devices in the range from 6-8.5 GHz, subjected to the technical limits embossed by FCC in the US. Therefore one of the main goals is to find an optimal planar-antenna working in the European (UWB) spectrum 6-8.5 GHz, with a bandwidth of 2.5 GHz. The different ntypes of antennas investigated are the dipole antenna, the square antenna (basic square antenna, square antenna with bevel, square with off set) and the circular disc antenna, designed and simulated in Advance Design System (ADS). Planar antennas implemented in this project have a multi layer PCB structure which includes a flexible foil. The design process is mainly carried out in two steps. In the first step dimensions of antennas were calculated, then in the second step dimensions were tuned until the simulation result fulfilled the demands of the design specification. The characteristic input impedance, bandwidth, gain, directivity and electromagnetic radiation pattern are compared among different types of planar antennas investigated. In this report the bandwidth the focus because it the major concern of the project. The Balun is used to adapt the signal between the antenna and the device (transmitter and receiver). When the Balun simulated together with a planar antenna small change in the bandwidth is observed. It found that there are four types of planar antennas (basic square antennas, square antenna with bevel, square antenna with offset and circular disc antenna) can be used in the Ultra Wideband spectrum 6-8.5 GHz .